Ultrasound biomicroscopic characteristics of theanterior segment in primary congenital glaucomaViney Gupta, MD, Randhir Jha, MD, Geetha Srinivasan, MS, Tanuj Dada, MD,and Ramanjit Sihota, MD, FRCS

PURPOSE To evaluate qualitatively and quantitatively ultrasound biomicroscopic (UBM) features ofthe anterior segment in eyes with primary congenital glaucoma.

METHODS UBM of 45 eyes of patients with primary congenital glaucoma (39 previously operated and6 unoperated eyes) and 28 control eyes were included in this study. UBM parameters werecorrelated with ocular biometry. Iris thickness, ciliary body thickness, ciliary body–lensdistance, posterior chamber depth, and anterior chamber angle were measured andcompared with control eyes. Other features of the anterior segment were qualitativelyevaluated.

RESULTS A thin, stretched-out ciliary body and abnormal tissue at the iridocorneal angle werefeatures seen in 90% of UBM scans. Iris thickness and stretched zonules correlated withthe axial length (r � �0.6 and 0.58, respectively; p � 0.04) but not with the mean cornealdiameter. Abnormal insertion of the ciliary body to the posterior surface of the iris wasnoted in eight eyes (17%).

CONCLUSIONS The present study documents characteristic anterior segment dysplasia and ciliary bodyanomalies in patients with primary congenital glaucoma. ( J AAPOS 2007;11:546–550)

A nderson,1 while studying histopathological sectionsof eyes with congenital glaucoma, found a band oftissue stretching from the root of the iris to the

Schwalbe’s line, misinterpreted by many including Barkan2 asan opaque membrane. He hypothesized that these thick tra-becular sheets prevent the posterior sliding of the uveal tractagainst the inner surface of corneoscleral envelope and thatconsequently the ciliary processes, ciliary muscle, and irisbecome anteriorly placed. This abnormal tissue associatedwith the anterior displacement of the uveal tract has beenpostulated as the reason for blockage of the trabecular mesh-work and consequently glaucoma in these children. Exposureto high intraocular pressure (IOP) while the ocular coats arenot fully mature in children leads to secondary changes likeincreased axial length and associated myopia, iris thinning,and increased corneal diameters.3

There are very few studies on ultrasound biomicroscopiccharacteristics of the anterior segment in eyes with primarycongenital glaucoma.4,5 The purpose of the present studywas to find the anatomical correlation of anterior segmentmorphology as evaluated by ultrasound biomicroscopy

Author affiliations: Dr Rajendra Prasad Center for Ophthalmic Sciences, All IndiaInstitute of Medical Sciences, New Delhi, India

Submitted March 28, 2007.Revision accepted June 24, 2007.Published online August 28, 2007.Reprint requests: Viney Gupta, MD, Assistant Professor of Ophthalmology, Dr RP

Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi 29,India (email: gupta_v20032000@yahoo.com).

Copyright © 2007 by the American Association for Pediatric Ophthalmology andStrabismus.

1091-8531/2007/$35.00 � 0doi:10.1016/j.jaapos.2007.06.014

546

with biometric parameters such as corneal diameter andaxial length, which are consequences of globe stretching.

Materials and MethodsForty-five patients including children with newly diagnosed andpreviously operated (trabeculectomy with trabeculotomy withthe use of mitomycin) primary congenital glaucoma were ana-lyzed in this cross-sectional study. Exclusion criteria were apha-kic eyes, those with secondary glaucomas, children less than 5years of age, and those uncooperative for UBM (UBM P-40;Paradigm Medical Industries, Salt Lake City, UT) examination.Only one eye of each patient was included in the study amongpatients who had both eyes affected.

Contralateral healthy eyes of those with unilateral congenitalglaucoma were evaluated on UBM for comparison.

The study was conducted in line with the tenets of the Dec-laration of Helsinki and was conducted with the approval of theInstitutional Review Board of our institute. Informed consentwas obtained in all cases.

Ultrasound biomicroscopic (UBM) examination was per-formed in the supine position after instillation of topical anes-thesia; the specially designed scleral cup was fixed to the patients’eyes and 5% freshly prepared methyl cellulose was used as acoupling medium. UBM was performed with a 50 MHz trans-ducer at the inferior limbus in all cases to avoid the superior siteof surgery. The output of the UBM was stored on a computer foranalysis using the UBM Pro 2000 software. The UBM scanswere coded and analyzed by an independent trained observer(RJ), who was not informed about the diagnosis.

Limbus-to-limbus corneal diameter was measured in both ver-tical and horizontal meridia using vernier calipers. Biometric

parameters analyzed were axial length and lens thickness, which

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osterior

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were measured on Sonomed PacScan 333AP machine (Latham &Phillips Ophthalmic Products Inc., OH).

The techniques for measuring various parameters on UBMscans is given below. Details of the measurements evaluated aredepicted in Figure 1A (Figure 1B shows a control eye). Iristhickness was measured across a vertical line located 500 �mcentrally from the most probable location of the scleral spur.Anterior chamber angle was measured by constructing a linealong the inner surface of the cornea into the anterior chamberrecess and joining it with a line on the anterior iris surface.Ciliary body–lens distance (zonular length) was measured from astraight line extending from the tip of the ciliary processes to thelens equator. Ciliary body thickness was measured along the linestarting from the point of anterior-most attachment of the ciliarybody to the sclera to the beginning of the zonules. Posteriorchamber depth was measured along a vertical line 1 mm centralto the root of the iris.

All measurements were analyzed for one eye if both eyeswere eligible (the eye being selected by computer-generatedrandomization).

Statistical AnalysisSPSS software (version 10.0, Chicago, IL) was used for compar-ing the parameters between the glaucomatous and control eyes.Differences in the parameters between the two groups werecompared using Student’s t-test. Correlations were performedbetween the axial length and corneal diameters and betweenthese biometric parameters and the UBM parameters in eyeswith primary congenital glaucoma. A p-value of �0.05 was con-sidered statistically significant.

ResultsMean age of the patients was 13.8 � 3.2 years (range, 7-27

FIG 1. (A) Schematic lines for measurements on the UBM scan. PCD: p

years). There were 27 male and 18 female patients. Among

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the controls, there were 18 males and 10 females with anaverage age of 14.1 � 4.5 years. Except for six (13.3%)eyes that presented late and had no previous surgery forcongenital glaucoma, the eyes had previously been oper-ated with superior site trabeculectomy with trabeculotomyand use of mitomycin. Among the 39 (86.7%) operatedeyes evaluated, 4 had been operated twice, while the othershad undergone a single operation previously. IOP was notmeasured for the purpose of the study and therefore is notprovided. The average spherical refractive error in con-genital glaucoma eyes was �6.3 � 4.8 D, significantly ( p �0.004) more myopic than that of control eyes (�0.6 � 1.2 D).

BiometryThe biometric and UBM parameters differed significantlybetween the control (Figure 1B) and glaucomatous eyes(Figure 2A-D) (Table 1).The lens was significantly smallerin glaucomatous eyes compared with controls. There wasno detectable correlation between the axial length and thecorneal diameter or the axial length and the lens thickness(r � �0.3, p � 0.35) in either control or glaucomatouseyes.

Iris Thickness. Iris thickness was moderately nega-tively correlated with axial length in eyes with primarycongenital glaucoma (r � �0.6, p � 0.04). However, theiris thickness was not detectably correlated with cornealdiameters in these eyes (r � �0.3, p � 0.35).

Anterior Chamber Angle. The angle was wider ineyes with congenital glaucoma than in controls but did notcorrelate with the axial length or with the corneal diame-ters in these eyes (r � 0.1, p � 0.2).

Ciliary Body Lens Distance (Zonular Length). The

chamber depth. (B) UBM scan of the normal eye.

zonules were more elongated in congenital glaucoma eyes and

Posterior chamber depth (mm) 0.2 � 0.4 0.78 � 0.2 0.03

Volume 11 Number 6 / December 2007548 Gupta et al

their length correlated with the axial length (r � 0.58, p � 0.04)but not with the corneal diameters (r � 0.22, p � 0.11).

Ciliary Body Thickness. The ciliary body in congen-ital glaucoma eyes was thinner than in control eyes. How-ever, its thickness correlated neither with axial length norwith corneal diameters (r � �0.2, p � 0.11; r � �0.1, p �0.55), probably due to a wide variation in its morphologyin these eyes.

Posterior Chamber Depth. The posterior chamberwas wider in congenital glaucoma eyes compared withcontrols ( p � 0.03).

Qualitative Features. Abnormal tissue at the iridotrabecular angle was seen in 41 (91%) of the scans. In 32of the 45 (71%) scans rarefaction of the ciliary body was

retched out ciliary body (long white arrow), markedly elongated zonules (Fws) and ciliary body inserted at the posterior surface of the iris (Fig D, Ble. Figure 2A & 2C show the rarefied ciliary body.

FIG 2. (A-D) UBM of eyes with congenital glaucoma. Fig A&B showing a st ig C)(white arrow heads), elongated ciliary processes (Fig A&B) (thick white arro lackarrow). The abnormal tissue at the angle has been shown by a dotted circ

Table 1. Quantitative measurements of the biometric and ultrasoundbiomicroscopic parameters between control eyes and those withprimary congenital glaucoma

Controls(n � 28)

Congenitalglaucoma(n � 45) p-value

Horizontal corneal diameter (mm) 11.6 � 1.4 13.8 � 1.1 0.003Vertical corneal diameter (mm) 11.4 � 1.2 13.3 � 0.9 0.003Axial length (mm) 22.5 � 2.5 26.1 � 2.4 0.01Lens thickness (mm) 3.8 � 0.4 2.9 � 0.3 0.02Iris thickness (mm) 0.5 � 0.09 0.37 � 0.1 0.026Anterior chamber angle (deg) 22 � 8.5 38 � 10 0.004Ciliary body lens distance

(zonular length in mm)0.8 � 0.2 1.49 � 0.4 0.000

Ciliary body thickness (mm) 1.1 � 0.25 0.8 � 0.3 0.03

noted. The ciliary body was stretched out in 10 cases

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(22%); ciliary processes were elongated, and ciliary bodywas inserted at the posterior surface of the iris in eight eyes(17%) (Figure 2A-D).

DiscussionThe eyes of congenital glaucoma patients are known tohave greater corneal diameters, greater axial length, andhigher myopic refractive error.3 This was true in the glau-comatous eyes of our patients compared with controls.Our observations appear to be summation effects of anom-alies that produce elevated IOP, secondary effects of ele-vated IOP on young eyes, and healing and remodeling ofthese eyes over time.

Compared with control eyes, the eyes with congenitalglaucoma were significantly more myopic. Myopic non-glaucomatous eyes are known to have greater anteriorchamber depth, thinner lenses, and greater axial lengths.6

Axial myopia has also been found to be associated withhigher IOP, although other studies refute the association.7

Along with features of significantly increased corneal di-ameters and increased axial length, thinned out iris andciliary body anomalies were characteristic of congenitalglaucoma in our study.

A previous description of the UBM findings in congen-ital glaucoma emphasized the unique morphology of theciliary body with massively elongated processes.5 Thestretching is probably due to the enlarging diameter of theeye, creating traction on the zonules attached to a nonen-larging lens. These elongated zonules also cause thegreater mobility of the lens in these eyes. This elongatedtissue might be drawn into the trabeculectomy cleft, ac-counting for the high incidence of uveal tissue incarcera-tion as noted in previous studies.2,7-10

Another interesting finding in these eyes was a thin,stretched-out and rarefied ciliary body. Wang and Ouy-ang11 also noted a small and ill-defined ciliary body in 10eyes of patients with congenital glaucoma on UBM. Insome of our patients abnormalities in the ciliary bodyincluded the ciliary processes originating from the poste-rior surface of the iris. Such anomalous positioning of theciliary body makes it liable to nicking during an iridec-tomy. This finding should be considered while operatingon these cases for trabeculectomy or even cataract surgery,as these cases warrant a careful iridectomy lest there beinjury to the ciliary body or vitreous prolapse.

We detected no correlation between axial length orcorneal diameter with the morphology of the ciliary body.Whereas Oliviera et al12 found an increasing ciliary bodythickness with increasing axial myopia in nonglaucoma-tous eyes, we found a weak negative correlation of the axiallength with the ciliary body thickness, probably due to theeffect of raised IOP in these eyes. However, the moderatenegative correlation between iris thickness and axial lengthis of interest in that it denotes the thinning of the iris withprogressive stretching of the globe in these eyes. Axial

length has also been known to be closely correlated with

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increasing IOP in the postoperative period in eyes withcongenital glaucoma.13 Compared with control eyes, thelens in congenital glaucoma eyes was much smaller. Sam-paolesi and Caruso3 also found the lens to be smaller ineyes with congenital glaucoma compared with the lens innormal infants. Garner et al14 in their longitudinal studydescribed a thinning of the lens in myopic children of0.005 mm/yr compared with their nonmyopic counter-parts over the years. However, even their calculation doesnot account for the extreme thinning of the lens seen inthe congenital glaucoma eyes in our study.

Limiting the present study was the fact that all measure-ments were taken by a single unmasked observer and weretherefore subject to observer errors. Since the scleral spurwas not well defined in these eyes, measurements needingscleral spur identification were based on the approximatelocation of the spur from the observer’s experience. Also,the IOP of the patients was not taken into account duringthe study, although all operated eyes had past records ofhigh IOP for which they had undergone filtering surgery.Notwithstanding the limitations, we believe that thepresent study is the only one to provide quantitative in-formation about anterior segment morphology in a largenumber of eyes with congenital glaucoma. The anatomicalinformation gleaned in the study might be useful in plan-ning anterior segment surgery in these eyes.

Literature SearchWe used the PubMed database for literature search usingthe words congenital, glaucoma, and ultrasound biomicroscopyseparately and together. The search was conducted on allEnglish articles in this database from 1981 onward.

References1. Anderson DR. The development of the trabecular meshwork and its

abnormality in primary infantile glaucoma. Trans Am OphthalmolSoc 1981;79:458-85.

2. Barkan O. Pathogenesis of congenital glaucoma. Gonioscopic andanatomical observation of the anterior chamber in normal eyes andcongenital glaucoma. Am J Ophthalmol 1955;40:1-11.

3. Sampaolesi R, Caruso R. Ocular echometry in the diagnosis ofcongenital glaucoma. Arch Ophthalmol 1982;100:574-7.

4. Dietlein TS, Engels BF, Jacobi PC, Krieglstein GK. Ultrasoundbiomicroscopic patterns after glaucoma surgery in congenital glau-coma. Ophthalmology 2000;107:1200-5.

5. Azuara-Blanco A, Spaeth GL, Araujo SV, Augsburger JJ, Katz LJ,Calhoun JH, et al. Ultrasound biomicroscopy in infantile glaucoma.Ophthalmology 1997;104:1116-19.

6. Nomura H, Ando F, Nino N, Shimokata H, Miyake Y. Therelationship of intraocular pressure and refractive error adjustingfor age and central corneal thickness. Ophthalmol Physiol Opt2004;24:41-5.

7. Lee AJ, Saw SM, Gazzard G, Cheng A, Tan DT. Intraocular pres-sure associations with refractive error and axial length in children.Br J Ophthalmol 2004;88:5-7.

8. Dietlein TS, Jacobi PC, Krieglstein GK. Prognosis of primary abexterno surgery for primary congenital glaucoma. Br J Ophthalmol1999;83:317-22.

9. Bruke JP, Bowell R. Primary trabeculectomy in congenital glaucoma.

Br J Ophthalmol 1989;73:186-90.

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10. Worst JFF. The Pathogenesis of Congenital Glaucoma. Assen, Neth-erlands Royal Van Gorcum; Springfield, IL: Charles C. Thomas, 1966.

11. Wang N, Ouyang J. The real time observation of anterior segment ofprimary congenital glaucoma. Yan KeXue Bao 1998;14:83-6.

12. Oliviera C, Tello C, Liebmann JM, Ritch R. Ciliary body thick-ness increases with increasing axial myopia. Am J Ophthalmol

2005;140:324-5.

13. Keifer G, Schwenn O, Grehn F. Correlation of postoperative axiallength growth and intraocular pressure in congenital glaucoma—Aretrospective study in trabeculotomy and goniotomy. Graefes ArchClin Exp Ophthalmol 2001;239:893-9.

14. Garner LF, Stewart AW, Owens H, Kinnear RF, Frith MJ. TheNepal Longitudinal Study: Biometric characteristics of developing

eyes. Opt Vis Sci 2006;83:274-80.

First Person

A 5-year-old patient defined lazy eye as “an eye that sits on the couch, drinks beer, andwatches TV.”

—Al Cossari, MD

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