FACULTY PROFILE: Kevin Houston

FEATURED REVIEW: Bioptic Update

CLINICAL REVIEW AND RESEARCH: Relation of Height to Refractive

Error and Ocular Optical Components. Literature Review and

Additional Data

OPTOMETRY HISTORY: IU Alumnus Gary Campbell Produces

Monograph on the History of American Phoropters.

ARTICLE OF INTEREST: Mirror Symmetry of Astigmatic Axes

BOOK REVIEW: Proust was a Neuroscientist

Summer 2009Volume 12, Numbers 1/2

Profiled in this issue is a faculty member relatively new to the IU faculty, Kevin Houston.Dr. Houston is an alumnus of Indiana University School of Optometry. For the featuredreview, he provides an update of bioptic systems for persons with reduced visual acuity.Work by another alumnus, Gary Campbell, is also discussed in this issue. He hasproduced a monograph on the history of American phoropters. Also in this issue are aliterature review on the relation of height and refractive error, a review of an article oninterocular symmetry of astigmatic axes, and a review of a book on the relation of artand science.

David A. GossEditor

In This Issue

Correspondence and manuscripts submitted for publication should be sent to the Editor: David A.Goss, School of Optometry, Indiana University, Bloomington, IN 47405 USA (ordgoss@indiana.edu). Business correspondence should be addressed to the Production Manager:J. Craig Combs, School of Optometry, Indiana University, Bloomington, IN 47405 USA (or jocombs@indiana.edu). Address changes or subscription requests should be sent to Sue Gilmore, Schoolof Optometry, Indiana University, Bloomington, IN 47405 USA (or sgilmore@indiana.edu).

Our appreciation is extended to Essilor of America for financial support of this publication.

Varilux® is a registered trademark of Essilor International, S.A

ON THE COVER: Figure 10 (page 4) in Kevin Houston’s Bioptic Update article

shows the view with the Conforma Bi-Level Telescope Apparatus.

Indiana University School ofOptometry Administration:

P. Sarita Soni, M.S., O.D., Interim Dean

Clifford W. Brooks, O.D., Director, Optician/Technician Program

Joseph A. Bonanno, Ph.D.,Associate Dean for AcademicAffairs

Rowan Candy, Ph.D., Associate Dean for Research

William Swanson,, Ph.D., Associate Dean for Graduate Programs

Sandra L. Pickel, B.G.S., A.S.,Opt.T.R., Associate Director,Optician/Technician Program

Cindy Vance,Director of StudentAdministration

Indiana Journal of Optometry

Editor:David A. Goss, O.D., Ph.D.

Editorial Board:Arthur Bradley, Ph.D.Clifford W. Brooks, O.D.Daniel R. Gerstman, O.D., M.S.Victor E. Malinovsky, O.D.Neil A. Pence, O.D.

Production and LayoutJ. Craig Combs, M.H.A.

Summer 2009Volume 12, Numbers 1/2

Table of Contents

TABLE OF CONTENTS

FACULTY PROFILE: Kevin Houston

by Todd Peabody ……………………………………….…… 2

FEATURED REVIEW: Bioptic Update

by Kevin Houston ………………..........................………… 4.

CLINICAL REVIEW AND RESEARCH:

Relation of Height to Refractive Error and Ocular Optical

Components. Literature Review and Additional Data

by David A. Goss and Vernon Dale Cox …….................... 7

OPTOMETRY HISTORY:

IU Alumnus Gary Campbell Produces Monograph on the

History of American Phoropters

David A. Goss ………………………………….......……….. 13

ARTICLE OF INTEREST:Mirror Symmetry of Astigmatic Axes,

by David A. Goss ………………..................................….. 14

BOOK REVIEW: Proust was a Neuroscientist

Reviewed by David A.Goss ...................................……… 16

Statement of Purpose: The Indiana Journal of Optometry is published by theIndiana University School of Optometry to provide members of the IndianaOptometric Association, Alumni of the Indiana University School of Optometry, andother interested persons with information on the research and clinical expertise atthe Indiana University School of Optometry, and on new developments inoptometry/vision care.

The Indiana Journal of Optometry and Indiana University are not responsible forthe opinions and statements of the contributors to this journal. The authors andIndiana University have taken care that the information and recommendationscontained herein are accurate and compatible with the standards generallyaccepted at the time of publication. Nevertheless, it is impossible to ensure that allthe information given is entirely applicable for all circumstances. IndianaUniversity disclaims any liability, loss, or damage incurred as a consequence,directly or indirectly, of the use and application of any of the contents of thisjournal. This journal is also available on the world wide web at:http://www.opt.indiana.edu/IndJOpt/home.html

Kevin Houston was born in Phoenixville,

Pennsylvania, but grew up in Lansing, IL, a

southern suburb of Chicago. Despite his

upbringing on the Southside of Chicago,

traditionally considered White Sox territory, Kevin

is a lifelong Cubs fan. In high school, Kevin was a

musician and an athlete,

excelling both on the baseball

diamond and on the French

horn in the high school band.

He went on to attend school

downstate at Eastern Illinois

University. He excelled in

Army ROTC there, earning his

Black Beret qualification. At

EIU, he earned his Bachelor

degree in Zoology and

Chemistry. Upon graduation,

Kevin spent a year teaching

kids about dinosaur fossils and

ecology as a Conservation Educator at Disney’s

Animal Kingdom in Orlando, FL.

Kevin gained admission to Indiana University

School of Optometry in fall 1999. As a student at

IUSO, Kevin was heavily involved in service, an

active member of Indiana University Optometric

Student Association, Volunteer Optometric

Services to Humanity, and Beta Sigma Kappa

Optometric Honor Society.

After graduating from optometry school in 2003,

Kevin worked in private practice in Mitchell,

Indiana. Influenced by his multiply handicapped

brother, Kevin found his niche working with special

populations. This eventually led him to Atlanta

Georgia to work at Gottlieb Vision Group, a clinic

internationally recognized for rekindle™, a

treatment for visual field loss. Here he gained

experience treating patients with vision loss due to

acquired brain injury and stroke, ocular disease,

and developmental disabilities. In 2006, he earned

fellowship in the American Academy of Optometry.

In January 2007 Kevin left private practice to teach

clinical low vision rehabilitation at IUSO.

The University clinics are specially equipped to

allow thorough evaluation of patients with serious

vision disturbance resulting from degenerative eye

conditions, congenital eye conditions, degenerative

neurological conditions, stroke, brain tumors,

automobile accidents, and aneurysm. These

patients typically have moderate to severe

reduction in visual acuity, glare disability,

constricted visual fields, visual spatial distortions,

visual processing disorders, color vision deficits,

double vision, poor balance and mobility, and

inability to perform activities of daily living. Kevin

also provides inpatient vision rehabilitation at the

Rehabilitation Hospital of Indiana.

In addition to his work in the clinic, Kevin has

developed a reputation for his speaking and his

research. He has given 26 lectures to various

groups in the professional community and has

been steadily working on cutting edge low vision

research. His current investigations include

prescribing trends of BiOptic telescope systems for

driving, minimum vision requirements for cell

phone use, and prism adaptation therapy for

unilateral spatial neglect. Throughout his time at

IU, Kevin has served as the Indianapolis Director of

Low Vision Services for IUSO as well as the

Director of Inpatient Optometric Services at the

Rehabilitation Hospital of Indiana.

In time away from the School, Kevin enjoys

photography, jogging as a member of the Indiana

University School of Optometry Running Team,

and spending time with family and friends. He and

his wife Lindsey treasure spending time with their

21 month old son Maddox Houston.

Page 1 ... Vol. 12, Nos. 1/2 ... Summer 2009 ... Indiana Journal of Optometry ..........................................

Faculty Profile: KEVIN HOUSTON, O.D.BY TODD PEABODY, O.D.

.................................................... Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 2

Introduction

Forty-five states in the United States currentlypermit people with moderately reduced visualacuity to drive with the aid of a bioptic telescopesystem (BTS).1 The driver will have reducedcentral vision with full peripheral vision and use a2x-5.5x telescope mounted on the top of the frameor drilled and cemented into the spectacle lens.The telescope allows the driver to quickly glance

between their regularlens, termed the carrier,and the magnified viewof the telescope inorder to see signs andother road hazards.The median estimatedtime spent viewingthrough the telescope isonly 5% of the time withthe most common tasksbeing spotting roadsigns, traffic lights, and

identifying road hazards.2

Galilean telescopes consist of a plus lensobjective and a minus eyepiece, creating anupright image with a relatively short tube length, asseen in Figure 1. The drawback is the relativelysmall field of view due to an internal exit pupil. Theexit pupil is the image of the entrance pupil, in thiscase the objective lens at the front of the scope, asseen through the eyepiece. Field of view in anytelescope design is maximized by having the eyeas close as possible to the exit pupil. In Galileanstyle bioptics, minimizing the eye to eyepiecedistance is essential. The small field of viewmakes Galilean telescopes significantly morechallenging to fit properly. Pupillary distance,telescope location, and angle of tilt must all beprecisely measured after adjusting the frame. Thecosmetically appealing small size of these devices

motivates doctorsand patients totolerate theirinconveniences.

Kepleriantelescopes have thedownfall of beingmuch larger andheavier than theirGalilean cousins,but are much easierto fit and use. Theyconsist of a plus objective, and plus eyepiece.This results in a longer focal length and an invertedimage, as seen in Figure 2. An inverting prism isneeded to create an upright image, furtherincreasing the weight. The exit pupil is a virtualimage outside the telescope, and can actually beobserved by looking at the bioptic from the rearand rocking it side to side. The clinician shouldsee the exit pupil as though it is floating out of theeyepiece, moving against the direction of thetelescope as it is slightlytilted left to right. When thebioptic is worn, this virtualimage allows the exit pupilof the telescope to alignwith the entrance pupil ofthe eye, therebymaximizing the field ofview. Higher powers up to10x can realistically be used if the patient has gooddexterity and understands the limitations in thevisual field.

Keplerian Bioptics

Ocutech VES®-II has been around for manyyears and is still a favorite of many of my patients.The characteristic design that has made this modeland the generations after it popular was the

Bioptic UpdateBY KEVIN HOUSTON, O.D.Abstract

Forty-five states in the United States currently permit visually impaired people with moderately

reduced visual acuity to drive with the aid of a bioptic telescope. A review of the major types of

bioptics prescribed are discussed in detail with fitting pearls. A review of the literature pertaining

to visual risk factors for motor vehicle crashes is presented and a protocol for the assessment of

potential driver rehabilitation patients is presented based on the latest research. Training

procedures are also outlined with an introduction to the use of a new computer aided training

software and discussion of the potential role for immersive driving simulators to improve the

safety of bioptic drivers.

Key words/phrases: Bioptics, driving, dynamic driver software, low vision

Figure 1

Figure 2

Figure 3

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periscope type designallowing the telescope to sitlength wise against theframe rather thanprotruding out (Figure 3).The VES II is still fit bypractitioners when thepatient requires the

telescope to sit up higher.This model is mounted on top of the frame and isnot drilled through the lens, requiring a larger headtilt forward to enter the bioptic. The half-eye frameis the only frame choice for this device.

Ocutech VES-Kis similar to the VES-II with the differencebeing the mountingof the telescope(Figure 4). Frameoptions include theaviator style OcutechK and the oval unisexstyles only. Drillingthe eyepiece through

the carrier lens increases the field of view bygetting it closer to the eye. The degree of head-tiltrequired is less, facilitating quicker spotting.

Ocutech VES-Autofocus is currently still theonly commercially available autofocus bioptictelescope (Figure 5). This device is useful whenhands free focusing is required. The convenienceof autofocus is literally outweighed by the size ofthe device at 2.5 ounces and the hassle of thebattery pack. The autofocus mechanism isrelatively outdated and contains some of theglitches common to older autofocus cameras. Withprudent foresight, the engineers fashioned the

device with anautofocus lock toprevent mis-focusing duringdriving. Theautofocus is onlyavailable in 4x withthe standard 12degree field of view.Ocutech plans to

release a newautofocus telescope in the summer of 2009 whichthey promise will provide significant advancementsin this type of technology.

Ocutech VES Mini, as its name indicates, is anew compact design. It is optically similar to theother VES models being a Keplerian with theperiscope type design. However, instead of

attaching to the top ofthe frame, it is drilledinto the carrier lens(Figure 6). The majoradvantage has beenthe 15 degree field ofview and the ability todo a binocular mount.Despite its smallersize, most patientsconsider it less cosmetically appealing than theother VES models. Ocutech is planning tointroduce a smaller and cosmetically superiorGalilean model sometime in the next 12 months.

Ocutech VES Sport is the newest addition tothe bioptic telescope market (Figure 7). It is mostsimilar to the VES-K, with several improvements.1) The optics are noticeably sharper and brighter,2) the housing is more sleek and comes in differentcolors, 3) the near focus of the 4x is 7 inchescompared to 9 inches on the VES-K, 4) there is aparallax correction for image shift that occurs whenusing the device at near, and 5) refractivecompensation without an eyepiece lens is alsobetter, up to +/-15. The field of view, frameoptions, and weight are the same. I have a couplepatients who use the device for near andintermediate tasks in addition to the traditionaldistance use. However, most patients who chooseto upgrade do so for the cleaner optics andappearance.

Designs for Vision Expanded field spiraltelescope systems (EFTS) is a series of Keplerianscopes that have been a mainstay in the field ofbioptics for years. The optics are very crisp; someof the best available. A wide range of powers arepossible up to 10x. Downfalls include their weightat 4 ounces compared to the VES at 0.9 ounces,smaller 4x field of view at 9 degrees compared tothe VES’s 12.5 degrees, and poor cosmesis. Thetelescope protrudes directly out of the lens makingfor a frontheavy system.As the deviceages the weightwill commonlycause themounting toloosen or crackthe carrier lens. The large size also occludesmuch of the driver’s visual field. The nice optics ofthis device persuades many of my patients who donot mind the weight to stick with this design.

The Beecher Mirage is a set of head-mountedbinoculars (Figure 8). Brightness and field of view

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

is the best on the market with 15 degrees in the 4x.Unlike most bioptics, it is not drill mounted into acarrier lens. If carrier lens prescription is needed,the bridge can be adjusted to allow a frame to fitunder the bioptic. The eyepieces can be easilyadjusted for PD allowing a technician to fit andadjust the device. The clinician can prescribe thisbinocular bioptic without having to be concernedthat it will come out of alignment and cause thepatient to see double, as is the case with othermodels. The wide field of view makes it anexcellent option for older patients who might haveproblems adapting to the smaller field of view ofother bioptics. The mirage is also available in a5.5x with a field of view comparable to most 4xmodels. This is likely why Indiana amended itsbioptic driving law to allowing patients to drive withthe 5.5x Mirage, whereas 4x is the magnificationlimit for all other devices. Eschenbach introduceda new mounting for the Mirage last year that looksmore like a glasses frame and provides morestability than the old strap design seen in Figure 8.The disadvantage of the Mirage is its 3 oz weight,large size, and poor cosmesis; which manypatients will find tolerable in exchange for its easeof use and superior optics. Powers available up to8x are not eligible to use for driving, butnonetheless it works well to improve orientationand mobility in the severely and profoundly visuallyimpaired.

Galilean Bioptics

Conforma’s Bi-Level Telescopic Apparatus(BITA) is a miniature Galilean telescope and hasbeen available since the 1980's. I still find it to bethe best of the microgalilean bioptics. It comes in a3/8ths and 1/2 inch sizes from 2.5x-6x (Figure 9).The field of view will discourage some patients, but

I have not found it tobe an issue once it ismounted in its carrierlens. The telescope isnot cemented into thecarrier and can be slidback to minimize thevertex distance andincrease the field ofview. The clinician can

specify whether the focusing apparatus is in thefront of the carrier lens, or in the rear. Peripheralvision is not obstructed due to the small size of thetelescope, creating a magnified imagesuperimposed on top of the normal field (Figure10). This allows the patient to retain full peripheralvision, depth perception, and spatial orientation

while lookingthrough thetelescope. Thetelescopes canbe mounted inthe biopticposition or onthe visual axis; amethod calledsimulvision. Ihave fit this bothways and eitherway seems to work well. With a good fit the 4xgets a 10.5 degree field of view; significantly lessthan Keplerian models, but tolerable for manypatients when weighed against its cosmetic upside.

Designs for vision (DFV) also makes atelescopecomparable tothe BITA calledthe microspiralgalilean,although I havenot everattempted fit thisdevice. The visual field of the 4x is 5 degrees andit can be mounted in the bioptic position or on thevisual axis, similar to the BITA’s simulvision.

Eagle Eye II by Designs for Vision is probablythe most cosmetically appealing bioptic currentlyavailable (Figure 11). The objective sits flush withthe carrier lens, hiding most of the telescopebehind the lens. I often tint the carrier and haveused mirrored clip-ons to completely cover thescope. Unfortunately it only comes in 2.2x, limitingit to only the most mildly visually impaired drivers.Because of the proximity of the eyepiece to the eyeand the relatively large objective and eyepiecediameter, the field of view is relatively good at 11degrees. The difference between this telescopeand the Model II bioptic is the mounting. TheModel II protrudes 2-3 mm out of the front of thelens, but is still a very cosmetically acceptableoption. The Eagle Eye II has a ball and socketmounting that allows the telescope to be adjustedto maximize alignment.

We still have some patients in the DFVfocusable (spiral) and fixed focus Galileansystems. This is one of the most popular designsfor bioptic driving. It is very durable, has fixedfocus preventing the potential hazard of drivingwith a defocused telescope, can be mountedbinocularly, and is easily compatible with filters. Itdoes, however, have limitations of visual field at 6degrees in the 4x, and relatively poor cosmesis

................................................... Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 4

Figure 9

Figure 10

Figure 11

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compared to other Galileans.

Vision Requirements for Bioptic Driving in

Indiana

In order to be a candidate for bioptic driving, apatient must have:

• 20/200, better eye• Visual Acuity must reach 20/40 with

telescope (4x or less)• Visual field no less than 120 degrees

horizontal• Color vision adequate for traffic lights and

signs; red, yellow, green• Stable eye condition• No other co-morbidities• 30 hours on-the-road training with certified

driving rehab specialist (CDRS)• Approval of BMV medical advisory board• Annual review must be done by OD &

reported to BMV• Renewal every 4 years done by OD &

reported to BMV

Identifying High Risk Drivers

Not all patients who will meet the Indianavision requirements for the bioptic program will beable to successfully complete the program andobtain their license. The 30 hour on road trainingallows sufficient time for the driving specialist todiscover which patients will not be safe drivers.Unfortunately, this step comes at the end of theprogram after significant time and money has beenspent. Accurately predicting which patients have apoor prognosis for driver rehabilitation early in theprocess is a benefit to the patient bothpsychologically and fiscally. Recent researchstudies have allowed clinicians to better predict onroad performance.

The Salisbury Eye Evaluation (SEE) Study

The Salisbury Eye Evaluation Study wasconducted in Salisbury, Maryland from 1993-1995and the data on driving risk was published in April,2007. Salisbury is a semi-rural town of 24,000which is relatively grid-locked with four lane roadsand intersections with traffic signals. The drivingsituation in Salisbury is probably most similar totowns like Terre Haute and Kokomo, Indiana. Thiswas a retrospective study looking at 1801 driverrecords of individuals aged 65-84. It was the firststudy to look at multiple measures of visualfunction including Visual Acuity (VA), ContrastSensitivity, Glare, Stereo, Humphrey Visual Field(HVF), and Useful Field of View (UFOV). Theylooked for correlations between visual measures

and at-fault motor vehicle crashes. Resultsshowed that visual field was the most importantmeasure, followed by contrast sensitivity, and glaresensitivity. Greater than 20 points missed in theentire binocular field or greater than 10 pointsmissed in the inferior binocular field on the full-field81-point test translated to increased risk. Accidentrates likewise began to increase with contrastsensitivity measures less than 1.6 Log on the Peli-Robson test.3 The SEE study supports otherstudies that found contrast sensitivity to be a riskfactor for crash involvement.4

Other Important Studies

Several other studies have impacted the waywe evaluate patients in our clinics. Tests ofdivided attention have been found to be a goodpredictor of crash risk including both the UsefulField of View (UFOV) and the Trail-Making TestPart-B (TMT-B). We use the TMT-B because of itslong associated correlation to driving performanceand ease of administration. It is an extravagantversion of connect the dots, where the patient mustconnect number one to letter A, A to 2, 2 to B, andso on; alternating between numbers and letters.Studies have repeatedly shown the predictivevalue of this test for driving. Times were stronglyassociated with recent crash involvement in astudy of 1,700 drivers, on-road driving performancein a study with 105 drivers,5 and future at-faultcrash risk in a study with 2,508 drivers.6 The largesample sizes and strong statistical correlationsfrom these studies demonstrate the predictivepower of this test.

Recommended Bioptic Driver Protocol

Evaluation

The aforementioned research has lead to anew protocol for the evaluation of drivers thatincludes Full-Field 81 point field, contrastsensitivity using the Peli-Robson chart, glare acuitytesting, and TMT-B in addition to traditional visiontests. Data are analyzed and risk factors aretallied as 1) bioptic Snellen acuity worse than20/30, 2) contrast sensitivity less than 1.6, 3) >10points missing in the inferior binocular field or >20points missed on the entire binocular field, 4) largebilateral macular scotomata, 5) significant colordeficiency, and 6) glare disability greater than 2lines. Unstable or progressive vision conditionsare a separate risk factor that can carry moreweight at the examiner’s discretion. Prognosis isdetermined based on number of risk factors; 1being good, 2-moderate, 3-guarded, or 4-poor.With greater than 5 risk factors, the patient does

............................................Indiana Journal of Optometry ... Summer 2009 ... Vol. 12, Nos. 1/2... page 6

not a receive bioptic fitting for driving. Thisprotocol has been useful to help make objectiveand evidence based decisions in a situation wherean emotional patient may affect the clinician’sdecision. Without a set protocol, the practitionermay be pressured to move forward with trainingwhen it is not in the best interest of the patient.

Training

An evidence-based protocol cannot bedeveloped at this time for bioptic training due toinsufficient research. Systematic and uniformtraining on the use of the bioptic is important toallow these techniques to be studied and taught tofuture OD’s and driving specialists. New computerprograms and driver simulators offer opportunitiesto improve a patient’s skill with their bioptic. In ourclinic we are doing 3 to 4 one-hour visits usingstandard approaches such as stationary targetspotting on paper charts as well as novelcomputer-aided training using a projectedanimation program that has dynamic andtranslating targets in motion such as letters,arrows, and traffic signs. The program is calledDynamic Driver, Bioptic Training Program7 andcan be downloaded athttps://www.indiana.edu/~opt2/lvtrain/login.htmWe also use a projected video driving simulation inan attempt to achieve generalization of the skillslearned to the task of driving. More realisticimmersive simulators where the patient sits in a carcab that is interfaced with a video display arealready available. One such apparatus is theDriveSafety DS-600c. The patient sits in an actualcar cab with full driver controls including steeringwheel torque feedback and mirrors with integratedLDCs. It sits on a motion platform that providesinertial cues when the driver turns or brakes.Software allows for the creation of customizeddriving scenarios. While computerized trainingcannot replace on-road training, this type oftechnology may prove useful in maximizing skills ina safe environment. Control over the drivingscenario ensures that patients can be evaluatedand trained for the most important situations thatthey cannot be guaranteed to encounter duringtheir 30-hours on the road with the drivingspecialist. Trouble spots can be identified andrepeatedly practiced safely.

Conclusion

The bioptic market continues to see slow butsteady improvements in technology. Use oftraditional devices and training techniques incombination with novel computerized and virtual

reality technology offers new possibilities forimproving safety in this high risk population.

Disclosures

The author has no financial interest in theproducts or techniques discussed in this article.

Acknowledgements

The author thanks Ocutech, Conforma, andDesigns for Vision for providing technicalspecifications and photographs of their products foruse in this article.

References

1. Nolan J. An overview of bioptic driving: history,regulations, and practical experiences. Visibility,News and Research from the Envision Low VisionRehabilitation Center 2009; 3(2): 5-7.2. Bowers AR, Apfelbaum DH, Peli E. Bioptictelescopes meet the needs of drivers withmoderate visual acuity loss. Invest Ophthalmol VisSci 2005;46:66-74.3 Rubin GS, Ng ES, Bandeen-Roche K, Keyl PM,Freeman EE, West SK. A prospective, population-based study of the role of visual impairment inmotor vehicle crashes among older drivers: theSEE study. Invest Ophthalmol Vis Sci2007;48:1483-1491.4. Owsley C, Stalvey BT, Wells J, Sloane ME,McGwin G Jr. Visual risk factors for crashinvolvement in older drivers with cataract. ArchOphthalmol 2001: 119:881-887.5. Wang C, Kosinski C, Schwartzberg J, ShanklinA. AMA’s Physician's Guide to Assessing andCounseling Older Drivers. Washington, DC:National Highway Traffic Safety Admin; 2003.www.ama-assn.org/ama/pub/category/10791.html6. Vance DE, Roenker DL, Cissell GM, EdwardsJD, Wadley VG, Ball KK. Predictors of drivingexposure and avoidance in a field study of olderdrivers from the state of Maryland. Accid AnalPrev 2006;38:823-831. Epub 2006 Mar 20.7. Houston, K. Dynamic Driver, Bioptic. 2007.https://www.indiana.edu/~opt2/lvtrain/login.htm.

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Many theories of myopia development andemmetropization involve various aspects of

ocular growth.1-7 According to some of thesetheories, metrics of general body growth, such asheight, could be expected to be correlated withrefractive error and ocular optical components,such as axial length. The purpose of this paper isto review studies of the relation of height torefractive error and ocular components. Inaddition, some previously unpublished data will bepresented.

Literature Review

Johansen8 reported on the heights of 527boys, ages 12 to 15 years, from seven differentschools in Denmark. Forty-three of the boys hadmyopia, which ranged from -0.50 to -7.00 D, andwhich averaged -2.6 D. Mean heights werenumerically greater among the myopes than thenon-myopes at each age: 2.1 cm greater amongthe 12 year olds, 1.8 cm greater at 13 years old,3.4 cm at 14 years, and 5.2 cm at 15 years. Thedifference in means was statistically significantonly for the 15 year olds. Heights variedconsiderably within both refractive groups, withstandard deviations in the separate refractive andage groups generally being between 6.5 and 7.5cm.

Two graduate thesis projects at IndianaUniversity studied the relationships between axiallength and height and other anthropometricmeasurements. Mohindra9 found a statisticallysignificant correlation of axial length and stature in35 males born in India. Subjects were 20 to 38years of age. Eighteen of the subjects weremyopic. The correlation coefficient of axial lengthand height was r = 0.57. Baldwin10 studied 40male myopes and 40 female myopes between theages of 17 and 36 years. Their myopia rangedfrom -0.50 to -13.50 D. Correlation coefficients ofaxial length with height were not statisticallysignificant: r = 0.12 in males and r = 0.01 infemales.

Goldschmidt11 reviewed a 1938 German study(Francke) that found that myopes under 6 D

averaged about 4 cm taller than emmetropes, butthat myopes over 6 D were not taller thanemmetropes. He also described a 1958 Frenchstudy (Benoit) which reported statisticallysignificant greater height in myopes than non-myopes. However, in Benoit’s study, whensubjects were divided into “peasants” andstudents, the differences in mean heights betweenmyopes and non-myopes were no longerstatistically significant.

Goldschmidt11 presented data for 3,511 mencalled up for military service examination inDenmark in the spring of 1964. Most of the menwere 18 to 20 years of age. Men who had myopiaof at least -0.50 D in at least one eye wereconsidered myopic; they numbered 491 of the3,511. The mean height of the myopic men was1.6 greater than the mean height of the non-myopic men (p<0.001). Goldschmidt divided thestudy population into six occupational categories(pupils and undergraduates, business men andoffice workers, advanced school or trade schooltraining, craftsmen, skilled workers, laborers andseamen). Myopic persons were not found to betaller than non-myopic persons in the sameoccupational groups. Students on average wereabout 5 cm taller than laborers, and myopia wasmuch more common among students than amonglaborers.

Another study of Danish military recruits wasperformed some 20 years later with the data from7,950 males in 1985 in eastern Denmark.12

Refractive data were taken from the power ofhabitual spectacles, or from contact lensprescriptions, or from refractive examination. Themean heights (with standard deviations inparentheses) for different refractive groups wereas follows: -5.75 to -8.00 D, 179.9 cm (6.4); -2.75to -5.50 D, 180.8 cm (6.4); -0.25 to -2.50 D, 180.4cm (6.7); 0 D, 179.6 cm (6.6); +0.25 to +2.50 D,180.9 (7.3); +2.75 to +8.00 D, 177.9 cm (5.4). Alltogether, myopes averaged 0.8 cm taller thanemmetropes and 1.0 cm taller than hyperopes.

In a study of 11 year old children in the UnitedKingdom, Peckham et al.13 presented data for a

Relation of Height to Refractive Error andOcular Optical Components: LITERATUREREVIEW AND ADDITIONAL DATABY DAVID A. GOSS, O.D., PH.D. AND VERNON DALE COX, PH.D.

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large group of children, of which 189 boys and 214girls had myopia. Children with myopia weresignificantly taller than children without myopia, thedifference being 1.0 cm. They noted that myopiawas more common in families with higher socialstatus and in families with fewer children. In ananalysis of variance the difference in heightbetween myopes and non-myopes was almostentirely accounted for by differences in socialstatus and family size.

Johnson et al.14 presented data for membersof a small Labrador community. They reportedstatistically significant correlations of height withrefractive error for subjects over the age of 20years. The correlation coefficients were: r = 0.42for Caucasian males (n = 30; p<0.025); r = 0.53 forInuit and mixed race males (n = 104; p<0.001); r =0.38 for Caucasian females (n = 15; p<0.1); r =0.28 for Inuit and mixed race females (n = 97;p<0.01). They did not give data for the relation ofheight and refractive error, but they stated that“The younger age groups who have the highestincidence of myopia tend to be taller than the olderpopulation…” They speculated that “It could bethat better hygiene and a higher calorie diet hasresulted in the younger population growing tallerthan their parents, with the penalty that their eyesare longer and therefore more likely to becomemyopic.”

Teikari15 reported on the relationship ofrefractive error and height in 690 twins in Finland.Subjects were surveyed to determine if they woreglasses. If they did, they were asked for a copy oftheir current prescription or the address of the eyecare provider. Those who were found to havespherical equivalent prescriptions of -0.25 D ormore minus were classified as myopes. Thosewho reported that they did not wear glasses andthat their vision was normal at far and near wereclassified as non-myopes. Height was obtainedfrom a questionnaire filled out by the subjects, whowere 30 or 31 years old at the time of thequestionnaire. The average height for myopicmales was 1.9 cm greater than for non-myopicmales, a difference which was statisticallysignificant (p=0.03). The mean height for myopicfemales was 1.0 cm more than for non-myopicfemales, but the difference was not significant(p=0.41). There were 43 twin pairs that had onemyope and one non-myope. In the twin pairsdiscordant for myopia, myopes were taller thannon-myopes among males, but no difference wasobserved among females.

Rosner et al.16 reviewed the computerizedexamination records of 106,926 consecutive male

17 to 19 year old military recruits in Israel. Myopiawas found when all recruits with less than 6/7.5unaided visual acuity in either eye had non-cycloplegic refractions performed. Non-myopeshad a mean height of 173.7 cm (n = 85,763; SD =6.7). Subjects with myopia of -0.25 to -3.00 D hada mean height of 173.2 cm (n = 10,315; SD = 6.9).For subjects with 3.25 to 6.00 D of myopia, themean height was 173.3 cm (n = 5,423; SD = 6.9),and for those with more than 6 D of myopia, it was172.8 cm (n = 1,637; SD = 7.1). Heights weresignificantly less for each of the myopia groupsthan for the non-myopes when statistically adjustedfor intelligence quotient, education, and ethnicorigin.

Wong et al.17 studied 951 Chinese adultsbetween the ages of 40 and 79 years (mean age,58.1 years). The correlation coefficient of heightwith spherical equivalent refractive error fromsubjective refraction was only r = -0.04. However,the correlations of height with axial length andcorneal radius were much higher (r = 0.33 for axiallength and r = 0.30 for corneal radius), and bothwere statistically significant (p<0.001). Being tallerwas still correlated with longer axial lengths andflatter corneas after controlling for age, sex,education, occupation, income, housing type, andweight.

A study of 1,449 Singapore Chinese children,ages seven to nine years, was published by Saw etal.18 Refractive error data used for analysis werethe right eye spherical equivalents fromautorefraction after instillation of cyclopentolate.Children with myopia of at least 3.00 D had a meanheight of 130.6 cm (SD = 7.2), while children withmyopia of 0.50 to 3.00 D had a mean height of127.6 cm (SD = 7.6). In children with emmetropia,the mean height was 126.5 cm (SD = 7.1),compared to 124.4 cm (SD = 7.2) for those withhyperopia. The difference between heights forhigher myopes and for emmetropes wasstatistically significant (p=0.042). The authors alsoseparated the data into quartiles by height. Whenthe means were adjusted for age, gender, parentalmyopia, books read per week, school attended,and weight, the children in the tallest quartile had0.46 mm longer axial lengths, 0.1 mm flattercorneas, and 0.47 D more myopia than the childrenin the shortest quartile. Statistical significance wasfound for the trends of longer axial length(p<0.001), flatter cornea (p<0.001), and moremyopia (p=0.002) with increasing height by quartileanalysis.

A study of Mongolian adults19 includedrefraction by non-cycloplegic autorefraction. There

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were 615 subjects on whom both refraction andheight data were obtained. Subjects ranged in agefrom 40 to over 70 years of age. The meanheights for different refractive errors levels were(with standard deviations in parentheses): morethan 5.0 D of myopia, 157.4 cm (7.8); -3.1 to -5.0D, 156.8 cm (10.8); -1.1 to -3.0, 156.7 cm (9.3); -0.1 to -1.0, 158.0 cm (7.5); 0 to +1.0 D, 158.7 cm(9.1); more than 1.0 D of hyperopia, 155.1 cm(8.7). The authors did not present a statistical testof relation of refractive error and height. Usingtheir means and standard deviations to perform t-tests, it was found that none of the separatemyopia group means differed significantly from themean for the emmetropia (0 to +1.0 D) group. Themean height for the low myopia group (-0.1 to -1.0D) was significantly greater than the mean heightfor the hyperopes (p<0.02), and the mean heightfor the emmetropes was significantly greater thanthat for the hyperopes (p<0.001).

Khandekar et al.20 studied a number ofvariables in Omani children in 7th grade and againin 10th grade. Subjective refractions were done,and spherical equivalents were used for analysis.In the 7th grade, 503 male myopes averaged 1.9cm taller than 647 male non-myopes, and 937female myopes averaged 0.9 cm taller than 766female non-myopes. Differences were statisticallysignificant. In the 10th grade, the male myopeswere significantly taller than the male non-myopesby an average of 1.4 cm, and the female myopeswere significantly taller than the female non-myopes by an average of 1.0 cm.

Ojaimi et al.21 reported data from a study of sixto seven year old children in Sydney, Australia.Included were 859 girls and 881 boys. Refractivedata used in the analysis were right eye sphericalequivalents from autorefraction after instillation ofcyclopentolate. Pearson correlation coefficientswere determined for the relation of height with thefollowing variables: with refractive error, r = 0.008;with axial length, r = 0.25 (p<0.0001); with steepestcorneal radius, r = 0.18 (p<0.0001); with flattestcorneal radius, r = 0.21 (p<0.0001). The authorsalso separated the data by height quintiles. In thequintile analysis, being taller was also significantlyassociated with longer axial length (p<0.0001) andflatter corneal radii (p<0.0001). Thoseassociations remained highly statistically significantwhen data were adjusted for age, gender, weight,and parental myopia.

Another study in Australia22 examined therelationship of height to refractive error in 690monozygotic twins and 534 dizygotic twins.Subject ages ranged from 18 and 86 years, with a

mean of 52 years. There were 823 females and401 males. Refractive error data were right eyespherical equivalents from autorefraction after theuse of tropicamide. Height showed a low butstatistically significant correlation with refractiveerror, r = -0.15 (p<0.01). Increasing height wascorrelated with greater axial length, with thecorrelation coefficient being r = 0.32. Height wasalso divided into quartiles. The tallest quartile was1.36 times more likely to be myopic, defined as aspherical equivalent refractive error of -0.50 D ormore minus, than the shortest quartile.

A few studies have reported longitudinal data.In a study of English children, Gardiner23,24

observed that rates of increase in height tended tobe greater in myopes than in non-myopes andgreater in progressing myopes than in stationarymyopes. Sorsby et al.25 reported that childrenwho had great increases in axial length did nothave exceptionally large increases in height in thesame period of time. Khandekar et al.26 foundthat myopes who progressed more than 0.50 D/yrfrom 7th to 10th grade had an average increase inheight of 12.5 cm compared to a 10.5 cm averageincrease in height in myopes who progressed 0.50D/yr or less during the same years.

Additional Data

Additional data to examine correlations ofheight with refractive error and the ocular opticalcomponents were compiled from subjects inOklahoma in various studies conducted atNortheastern State University27-30 and from theMyopia Clinic at the W.W. Hastings Indian HealthService Hospital in Tahlequah, Oklahoma.31

Subjects ranged in age from 7 to 40 years, butmost were between the ages of 8 and 30 years.The vast majority of subjects were Caucasian,Cherokee or other American Indian, or mixedCaucasian and American Indian. Corneal powerswere obtained from manual keratometry with eithera Bausch & Lomb keratometer or a Marcokeratometer. Axial length was measured byultrasonography, using one of three ultrasoundunits, Sonometrics Ocuscan 400, Cooper VisionUltrascan Digital AII, and Humphrey UltrasonicBiometer model 810. Refractive data were derivedas described in the individual studies. Right eyedata were used for analysis, except in cases whereleft eye data were more complete. Data for malesand females were considered separately becauseseveral studies have found greater axial lengthsand lesser corneal powers in males than infemales.25,28,30,32,33

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Pearson correlation coefficients were as follows inmales:Height and refractive error: r = -0.37, n = 911,p<0.0001Height and axial length: r = 0.42, n= 883, p<0.0001Height and keratometry: r = -0.06, n = 898,p=0.0915Axial length and refractive error: r = -0.73, n =1031, p<0.0001Keratometry and refractive error: r = -0.10, n =1046, p = 0.0009Axial length and keratometry: r = -0.36, n = 1017,p<0.0001

Pearson correlation coefficients were as follows infemales:Height and refractive error: r = -0.28, n = 1049,p<0.0001Height and axial length: r = 0.37, n= 1022,p<0.0001Height and keratometry: r = -0.10, n = 1033,p=0.0017Axial length and refractive error: r = -0.71, n =1183, p<0.0001Keratometry and refractive error: r = -0.11, n =1203, p<0.0001Axial length and keratometry: r = -0.38, n = 1167,p<0.0001

Increasing axial length was associated withmore minus refractive error, greater axial length,and lesser keratometer power. However, myopia,axial length, and height all increase with age, soage could be a confounding variable. Age wasfactored out using partial correlation coefficients.34

The partial correlations supported weakcorrelations of taller height with more minusrefractive error, greater axial length, and flattercorneas. The partial correlation coefficients wereas follows: Males, height and refractive error, r = -0.12,p<0.0005Females, height and refractive error, r = -0.08,p<0.01Males, height and axial length, r = 0.21, p<0.0001Females, height and axial length, r = 0.18,p<0.0001Males, height and keratometry, r = -0.12, p<0.0005Females, height and keratometry, r = -0.09,p<0.005

For subjects 20 years of age or more, meanheight was significantly greater for myopic (definedas any minus refractive error) males than for non-myopic (zero or plus refractive errors) males(p<0.05), but there was not a significant difference

in mean heights between myopic females and non-myopic females. For males 20 years of age andolder, the mean heights were 181.2 cm (n = 88; SD= 6.3) for the myopes and 177.8 cm (n = 27; SD =7.1) for the non-myopes. For the females, themean heights were 164.6 cm (n = 52; SD = 7.6) forthe myopes and 165.7 cm (n = 18; SD = 7.9) for thenon-myopes.

Comments

Most studies found greater average height inpersons with myopia than in persons withoutmyopia, but there were several studies that foundno difference and one study that found lesserheight in myopia. It is possible that differences inresults from study to study may be related todifferent ages and populations studied, as well asdifferent refractive measurement methods anddiffering classifications of myopia. Some studiesfound emmetropes and myopes to be taller thanhyperopes, but some studies grouped emmetropesand hyperopes together as non-myopes. Themajority of studies found a correlation of greaterheight with greater axial length and lesser cornealpower.

Current theories of refractive developmentsuggest an important role of ocular growth. Sometheories suggest a relationship of general bodygrowth and refractive development. For example,substances regulating ocular growth could besynergistic with substances regulating general bodygrowth. And some hypotheses positing a role fordiet in myopia etiology suggest greater heightwould be associated with myopia.5 Undoubtedlynumerous variables affect both refractivedevelopment and growth in stature, and there maybe some confounding variables. For example,higher socioeconomic status may be associatedwith both higher prevalence of myopia and greaterheight. Some studies continued to find anassociation of myopia with greater height whencontrolled for socioeconomic status. As with mostareas of refractive error investigation, definitiveanswers await further study.

References

1. Baldwin WR. A review of statistical studies ofrelations between myopia and ethnic, behavioral,and physiological characteristics. Am J OptomPhysiol Opt 1981;58:516-527.2. Bock GR, Widdows K, eds. Myopia and theControl of Eye Growth. Chichester: Wiley, 1990.3. Grosvenor T, Flom MC, eds. RefractiveAnomalies: Research and Clinical Applications.Boston: Butterworth-Heinemann, 1991.

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4. Goss DA, Wickham MG. Retinal-image mediatedocular growth as a mechanism for juvenile onsetmyopia and for emmetropization – a literaturereview. Doc Ophthalmologica 1995;90:341-375.5. Cordain L, Eaton SB, Miller JB, Lindeberg S,Jensen C. An evolutionary analysis of the aetiologyand pathogenesis of juvenile-onset myopia. ActaOphthalmologica Scand 2002;80:125-135. 6. Gilmartin B. Myopia: precedents for research inthe twenty-first century. Clin Exp Ophthalmol2004;32:305-324.7. Wallman J, Winawer J. Homeostasis of eyegrowth and the question of myopia. Neuron2004;19:447-468.8. Johansen EV. Simple myopia in schoolboys inrelation to body height and weight. ActaOphthalmologica 1950;28:355-361.9. Mohindra I. The Relationship between axiallength and certain anthropometric data, M.S.thesis, Indiana University, 1962.10. Baldwin WR. The relationship between axiallength of the eye and certain other anthropometricmeasurements of myopes. Am J Optom Arch AmAcad Optom 1964;41:513-522.11. Goldschmidt E. Myopia and height. ActaOphthalmologica 1966;44:751-761.12. Teasdale TW, Goldschmidt E. Myopia and itsrelationship to education, intelligence and height:preliminary results from an on-going study ofDanish draftees. Acta Ophthalmologica1988;66(supplement 185):41-43. 13. Peckham CS, Gardiner PA, Goldstein H.Acquired myopia in 11-year-old children. Br Med J,Feb 26,1977;542-544.14. Johnson GJ, Matthews A, Perkins ES. Surveyof ophthalmic conditions in a Labrador community.I. Refractive errors. Br J Ophthalmol 1979;63:440-448.15. Teikari JM. Myopia and stature. ActaOphthalmologica 1987;65:673-676.16. Rosner M, Laor A, Belkin M. Myopia andstature: Findings in a population of 106,926 males.Eur J Ophthalmol 1995;5:1-6.17. Wong TY, Foster PJ, Johnson GJ, Klein BEK,Seah SKL. The relationship between oculardimensions and refraction with adult stature: TheTanjong Pagar Survey. Invest Ophthalmol Vis Sci2001;42:1237-1242.18. Saw SM, Chua WH, Hong CY, Wu HM, ChiaKS, Stone Ram Tan D. Height and its relationshipto refraction and biometry parameters in SingaporeChinese children. Invest Ophthalmol Vis Sci2002;43:1408-1413.19. Wickremasinghe S, Foster PJ, Uranchimeg D,

Lee PS, Devereux JG, Alsbirk PH, Machin D,Johnson GJ, Baasanhu J. Ocular biometry andrefraction in Mongolian adults. Invest OphthalmolVis Sci 2004;45:776-783.20. Khandekar R, Al Harby S, Mohammed AJ.Ophthal Epidemiol 2005;12:207-213.21. Ojaimi E, Morgan IG, Robaei D, Rose KA,Smith W, Rochtchina E, Mitchell P. Effect of statureand other anthropometric parameters on eye sizeand refraction in a population-based study ofAustralian children. Invest Ophthalmol Vis Sci2005;46:4424-4429.22. Dirani M, Islam A, Baird PN. Body stature andmyopia – the Genes in Myopia (GEM) Twin Study.Ophthal Epidemiol 2008;15:135-139. 23. Gardiner PA. The relation of myopia to growth.Lancet 1954;266(6810):476-479.24. Gardiner PA. Physical growth and the progressof myopia. Lancet 1955;269(6897):952-953.25. Sorsby A, Benjamin B, Sheridan M. Refractionand its components during growth of the eye fromthe age of three. Medical Research CouncilSpecial Report Series no. 301. London: HerMajesty’s Stationery Office, 1961. 26. Khandekar R, Kurup P, Mohammed AJ.Determinants of the progress of myopia amongOmani school children: A historical cohort study.Eur J Ophthalmol 2007;17:110-116.27. Goss DA, Cox VD, Herrin-Lawson GA, DoltonWA. Refractive error, axial length, and height as afunction of age in young myopes. Optom Vis Sci1990;67:332-338.28. Goss DA, Jackson TW. Cross-sectional studyof changes in the ocular components in schoolchildren. Applied Optics 1993;32:4169-4173.29. Goss DA, Jackson TW. Clinical findings beforethe onset of myopia in youth: I. Ocular opticalcomponents. Optom Vis Sci 1995;72:870-878. 30. Goss DA, VanVeen HG, Rainey BB, Feng B.Ocular components measured by keratometry,phakometry, and ultrasonography in emmetropicand myopia optometry students. Optom Vis Sci1997;74:489-495.31. Schmitt EP. Vision care to Indian people inNortheastern Oklahoma: History and developmentof Northeastern State University College ofOptometry vision services. In: Goss DA,Edmondson LL, eds. Eye and Vision Conditions inthe American Indian. Yukon, OK: PuebloPublishing, 1990:191-203.32. Stenstrom S. Investigation of the variation andcorrelation of the optical elements of human eyes –Part III. Am J Optom Arch Am Acad Optom1948;25:340-350.

33. Francois J, Goes F. Ultrasonographic study of100 emmetropic eyes. Ophthalmologica1977;175:321-327. 34. Edwards AL. An Introduction to LinearRegression and Correlation, 2nd ed. New York:W.H. Freeman, 1984:43-45.

David Goss was a faculty member atNortheastern State University College ofOptometry in Tahlequah, Oklahoma, where thedata discussed in this paper were collected,from 1980 to 1992. He has been Professor ofOptometry at Indiana University since 1992.Dale Cox is a retired physicist. Hisprofessional positions included Professor ofPhysics at Northeastern State University inOklahoma and Research Scientist at Conoco,Inc., in Ponca City, Oklahoma.

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Gary L. Campbell, member of the IU School of Optometry Class of 1977, has authored and self-published a monograph entitled “Phoroptors: Early American Instruments of Refraction and Those

who Used Them.” He produced the paperback booklet of 99 pages in a 22 cm high by 14 cm wide format.In the title and throughout the book, he used the spelling phoroptor, an early spelling of the word, ratherthan phoropter, a common spelling today.

The production of this book in 2008 is timely, because 2008 marks the 100th anniversary of thesubmission of the patent application for the instrument that could be recognized as the first phoropter.

Henry DeZeng received the patent in 1909. The DeZeng phoropter, which he calledan Optometer, included spherical and cylindrical lenses, rotary prisms, Maddox rods,and an adjustable interpupillary distance setting.

In the foreword to the book, Campbell explained that as a collector of phoropters,he was disappointed to learn that there was no single source that he could use to findinformation about most historical phoropters. Instead, information was scattered overmany sources and had to be researched one phoropter at a time. As aconsequence, he decided to produce this monograph.

The front matter of the book includes a glossary of terms for persons not familiarwith the terminology used in the book. Chapters 1 through 3 (pages 21 to 30)provide a historical overview of the optical business and state of refraction just beforephoropters were developed. Chapters 4 through 6 (pages 33 to 59) discussinstruments which were precursors to phoropters, such as trial lenses, trial frames,optometers, and phorometers.

Chapters 7 through 11 (pages 61 to 89) are devoted specifically to phoropters. After a brief introductionto phoropters in Chapter 7, chapters 8 through 10 are organized to illustrate the evolution of particular linesof instruments made in the United States. In chapter 7, Charles Sheard is quoted as saying the following in1923 about Henry DeZeng’s 1909 phoropter patent: “From out of all this multiplicity of scientific ideals andseparate pieces of instrumentation – somewhat rough and crude and generally without calibration or opticalaccuracy – the inventive mind of Mr. DeZeng brought forth this first complete combination, convenientlyand mechanically properly fitted and adjusted, for refractive and muscular eye work.”

Chapter 8 starts with Henry DeZeng’s phoropter patented in 1909 and proceeds through the Phoro-Optometer to the No. 574, No.584, No. 588, No. 589, No. 593, and the AO Model 590 to the AO Rx Master.The AO Rx Master was the direct precursor to the AO Ultramatic Rx Master commonly used today.Chapter 9 discusses the Shigon/Woolf/General Optical/Shuron line of instruments. Patents received byNathan Shigon in 1910 and 1915 were transferred to the Woolf Instrument Corporation, whichsubsequently produced the Ski-Optometer Models 215 and 205. The patents were later transferred to theGeneral Optical Company and the Shuron Optical Company, which produced the Genothalmic Refractor.Chapter 10 deals with the Bausch & Lomb Greens and Greens II Refractors. The Greens Refractor wasintroduced in 1933 based on a 1931 patent by Clyde L. Hunsicker and work by Aaron S., Louis D., and M.I.Green. Chapter 11 briefly mentions some phoropters made outside the United States.

In an epilogue on page 91, Campbell notes that “Phoroptors have advanced significantly since the timeDeZeng, Woolf, General Optical, and the Greens first designed them. Improvements have beensubstantial and the competition has been hardy. Eventually Woolf, Shuron, and Bausch & Lomb stopped

IU Alumnus Gary Campbell ProducesMonograph on the History of AmericanPhoroptersBY DAVID A. GOSS, O.D., PH.D.

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making phoroptors. Only the line of DeZeng/American Optical prevailed and it has now achieved acentury of producing phoroptors in America.”

The monograph contains 31 figures, most of which are photographs or diagrams of phoropters. Thereare also pictures or diagrams of optometers, phorometers, and other instruments. A five-page listing ofreferences can be found on pages 93 to 97.

On page 91, Campbell suggests that “for those engaged in collecting optical instruments perhaps thissmall manual will be a helpful guide to identify and learn about phoroptors and other early Americainstruments of refraction.” I think that is an accurate statement, but I also found this book to be enjoyablereading. And it was interesting to read about some phoropters that I used extensively, but which ourcurrent students may never have seen, such as the Bausch & Lomb Greens Refractor and the AO RxMaster. Dr. Gary Campbell practices in Wheaton, Illinois. Copies of the book can be obtained for $10 bycontacting him at GaryLCampbell@gmail.com.

Mirror Symmetry of Astigmatic AxesBY DAVID A. GOSS, O.D., PH.D.

Ican recall being taught in optometry school that astigmatic axes tended to be mirror symmetric in thetwo eyes of an individual. In other words, if the axis for one eye was 105, the axis for the other eye

tended to be about 75. Or if the axis for one eye was 10, the axis for the other eye was usually about170. In the intervening years, that notion has seemed to me to be correct more often than not. A recentpaper has provided statistical support for that idea.

Guggenheim et al.1 examined spectacle prescriptions at 19 optometry practices in northern England.A total of 50,995 patients had an astigmatic component to their spectacle prescriptions for both eyes. Forpatients examined more than once, only the most recent prescription was used in the analysis.Astigmatism was specified in minus cylinder notation. The authors compared the relationship betweenright eye and left eye axes to the differences expected for a direct symmetry model and a mirrorsymmetry model. The direct symmetry model suggested that the exes were numerically about the samein the two eyes; in other words, the direct symmetry model suggests that axis 105 in one eye would tendto be found with axis 105 in the other eye, or if axis 10 was found in one eye the axis in the other eyewould usually be about 10.

The authors noted that axis 180 would essentially be the same as axis 0, with, for example, axis 180in one eye being only two degrees away from axis 2, not 178 degrees. To test for symmetry of axes, itwould therefore be necessary to add 180 to the axis of one eye in some cases or subtract 180 from theaxis of one eye in other cases. So for the direct symmetry model the absolute value of one of thefollowing differences would be expected to be very close to zero:

OD axis – OS axisOD axis – OS axis + 180OD axis – OS axis – 180

In the mirror symmetry examples given in the first paragraph above, the axes in the two eyes add to180. To test for mirror symmetry, one could see how far the sum is from 180. However, to take anotherexample, if the axes were 5 in one eye and 2 in the other eye, that individual would be 7 degrees awayfrom mirror symmetry (2 is 7 degrees away from 175), not 163 degrees (as would be suggested by 180minus the sum of 5 and 2). So for the mirror symmetry model, the absolute value of one of the followingwould be expected to be very close to zero:

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OD axis – (180 – OS axis)OD axis – (180 – OS axis) + 180OD axis – (180 – OS axis) – 180

The median absolute value for difference from direct symmetry was 20 degrees and the medianabsolute value for difference from mirror symmetry was 10 degrees. The difference in medians washighly statistically significant by the Wilcoxon signed ranks test. The authors did separate analyses of thedata by amount of astigmatism (greater than or less than 1.00 D), type of astigmatism (with-the-rule,against-the-rule, or oblique), and age decades (11-20 to 71-80). The median for difference from themirror symmetry model was significantly lower than the median for the direct symmetry model for bothamounts of astigmatism, for all three types of astigmatism, and for all seven age groups. These resultssupport the preponderance of mirror symmetry over direct symmetry.

Another way that the authors examined symmetry of right and left eye axes was by breaking theastigmatism down into J0 and J45 vector components. Any cylinder can be broken down into 90-180cross cylinder (J0) and 45-135 cross cylinder (J45) vector components. For axes of 90 and 180, J45would be zero. For axes from 1 to 89, J45 would have a positive value. For axes from 91 to 179, J45would be a negative number. So if J45 is the same sign in the two eyes, symmetry of axes to closer todirect symmetry. If the signs of the J45 values are opposite in the two eyes, symmetry of axes is closerto mirror symmetry.

Of the 50,995 subjects in the study, 18, 859 had a J45 of zero in one or both eyes. The number ofsubjects with differing J45 signs in the two eyes was 22,963, while 9,173 subjects had J45 values withthe same sign in the two eyes. Dividing 22,963 by 9,173, we find that the ratio of subjects with mirrorsymmetry of axes to subjects with direct symmetry of axes was 2.5 to 1.

The results of this study showed mirror symmetry of cylinder axes to be more common than directsymmetry. This was true for both higher and lower amounts of astigmatism, for all types of astigmatism(with-the-rule, against-the-rule, and oblique), and for all age decade groups from 11 to 80.

Reference

1. Guggenheim JA, Zayats T, Prashar A, To CH. Axes of astigmatism in fellow eyes show mirror ratherthan direct symmetry. Ophthal Physiol Opt 2008;28:327-333.

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Book Review:PROUST WAS A NEUROSCIENTISTREVIEWED BY DAVID A. GOSSProust was a Neuroscientist. Jonah Lehrer.Boston: Houghton Mifflin, 2007. xii + 242 pages.ISBN-10: 0-618-62010-9. ISBN-13: 978-0-618-62010-4. Hardcover, $24.00.

In today’s world, we are often lead to believe thatscience can solve every problem and answer

every question. In this book, author Jonah Lehrerimaginatively illustrates how various artists and

non-scientist writers offeredinsight into various aspects ofhuman existence decadesbefore science was able tounravel explanations of relatedneural function. In each of theeight chapters, the authordiscusses the work of an artist(five writers, one painter, onecomposer, and one chef) andthen neuroscience researchrelated to particular elements ofthe artist’s work. The artistsdiscussed are Walt Whitman(1819-1892), George Eliot(1819-1880), Auguste Escoffier

(1846-1935), Marcel Proust (1871-1922), PaulCézanne (1839-1906), Igor Stravinsky (1882-1971), Gertrude Stein (1874-1946), and VirginiaWoolf (1882-1941).

In the chapter dealing with Proust, forexample, the author notes that Proust hadobserved how memories change over time as theyare influenced by intervening events and hadincorporated examples of that in his novels.Decades later, neuroscience seems to show thatmemories are not represented as hard-wiredplaces in the brain, but rather as patterns ofsynapses which are strengthened or modified byexperience: “As long as we have memories torecall, the margins of those memories are beingmodified to fit what we know now…” (page 87).

One of the most interesting chapters was theone featuring famous chef Auguste Escoffier. Atthe time Escoffier worked, it was thought that thetongue was sensitive only to sweet, salty, bitter,and sour. Escoffier developed delicious recipesand promoted cooking that included little of thosefour known tastes. It has been discovered that hiscooking emphasized glutamate, for which receptorshave been discovered and which enhances tasteand deliciousness. In another chapter, not quite aswell done but related to vision, Lehrer notes that

Cézanne painted an interpretation of what he saw,rather than attempting to copy it. He goes on todescribe how an appreciation of Cézanne’spaintings requires imagination and interpretation,just as the visual cortex interprets input from theretina.

Some chapters make a clearer connectionbetween art and science than others, but one caneasily conclude that the book provides a caution toscience against arrogance and condescension. Ina final concluding chapter, Lehrer notes a“’communications gap’ between scientists andartists.” And he observes that “Each side wouldbenefit from an understanding of the other…” (page190). The author mentions that it is unfortunatethat many of the efforts of scientists to bring art andscience together have been characterized either byan attempt to make the humanities more likereductionist science, by an antagonism towardanything non-scientific, or by a poor understandingof the art being considered. In order to achieve are-integration of art and science, the “two existingcultures must modify their habits….the humanitiesmust sincerely engage with the sciences…and notignore science’s inspiring descriptions ofreality…the sciences must recognize that theirtruths are not the only truths….art is a necessarycounterbalance to the glories and excesses ofscientific reductionism, especially as they areapplied to human experience.” (page 197)

The author’s musings on the relation of artand science are interesting in their own right, but Icouldn’t help but thinking that they have a parallelin the relations of scientists and clinicians.Scientists try to design their experiments withcontrol for variables that might affect the outcomeof the study so that they can attribute the outcomesolely to the variable being intentionallymanipulated. Clinicians must deal with all thosepesky variables as part of the package that eachpatient represents. Just as art and science wouldeach “benefit from an understanding of the other,”clinical care and research work would each benefitif their practitioners strove to understand the goals,approaches, and skills of their counterparts.

The author, Jonah Lehrer, is a graduate ofColumbia University and studied at OxfordUniversity as a Rhodes Scholar. He is an Editor atLarge for Seed Magazine and a Contributing Editorfor Scientific American Mind. He is also the authorof the book “How We Decide.”

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