Methods: Goldmann applanation tonometers at the Univer-sity Eye Institute were measured for calibration accuracy atthe 20- and 60-mm settings using the instructions providedby the manufacturers. The process was repeated at 2 weeksand 5 months. Forty-two instruments were inferiorlymounted, and 32 were superiorly mounted.Results: At the initial reading, 50% were within the man-ufacturer’s � 0.5-mmHg calibration range for the 20-mmHg setting and 28.4% for the 60-mmHg setting. Whenthe acceptable error range was extended to �1.00 mmHg,56.8% were within the range for the 20-mm setting and62.2% for the 60-mm setting. Superior and inferior mount-ing types were equally likely to show errors.

By the 2-week evaluation, a significant number haddrifted outside the recommended range for the 20-mmHgsetting (P�0.039), but not for the 60-mmHg settings(P�0.404). A total of 40.54% had an error of �1 mmHg atthe 20 setting and 35.14% at the 60 setting. Of those initiallynot within the recommended range, greater error and vari-ability were noted. Neither mounting type had a greatertendency to show errors. At 5 months, the degree of errorsand the number out of calibration had increased. Fiftypercent of tonometers off at the 20-mm setting were nowalso out of calibration at the 60-mm setting. Inferior mountswere more likely to be out of calibration than superiormounts. Throughout the study, 13 tonometers showed errorsonly when read from a particular direction but not whentesting began from the opposite direction.Conclusion: Our findings indicate that calibration of Gold-mann tonometers should be tested more often than semian-nually or yearly and that the manufacturer’s recommendedrange of �0.5 mmHg may be impractical clinically. Inferi-orly mounted units may need to be examined more often.

Poster 72

Dolichoectasia in Association With Isolated SixthNerve PalsySarah Singleton, O.D., Jeanine Morasch, O.D.,Theresa Lee, O.D., Carla Engelke, O.D., andHuey-Fen Song, O.D., SAVAHS, 9055 E. Catalina Hwy10104, Tucson, Arizona 85749

Background: Dolichoectasia is best described as a patho-logically enlarged, tortuous, and dilated vessel, which canprecipitate neurological sequelae when located intracrani-ally. Patients with intracranial dolichoectasia may sufferfrom cerebral vascular accident, nystagmus, vertigo, dysar-thria, ataxia, hemiparesis, seizures, and isolated or multiplecranial nerve palsies. En route from the brainstem to theorbit, the abducens nerve can be affected by multiple com-plications most commonly related to trauma, microvascularinfarction, and compressive lesions. Since the abducensnerve exits the brainstem at the pons, it is susceptible tocompression if the vertebrobasilar artery is pathologicallyenlarged due to dolichoectasia. Imaging studies of the brainsuch as magnetic resonance imaging or angiography (MRI/

MRA) and computed tomography angiography (CTA) arenecessary to diagnose intracranial dolichoectasia. Treatmentincludes closely monitoring the abducens palsy, neurologi-cal consult, and strict hypertension control. If the palsy failsto resolve, microvascular neurosurgery may be performedto decompress the abducens nerve.Case Report: A 77-year-old white male presented withconstant binocular diplopia for 2 days. His medical historywas significant for coronary artery disease, hypertension,and hypertriglyceridemia. Corrected visual acuity measured20/20 O.D. and 20/30�1 O.S. Motilities showed a leftabduction deficit, and cover testing revealed an incomitantleft esotropia. Pupils were equal and reactive to light with-out afferent pupillary defect. The patient’s most recentblood pressure measurement was 110/67. Sedimentationrate, C-reactive protein, and glycosylated hemoglobin test-ing were all within normal limits. MRI of the brain revealeda vertebrobasilar dolichoectasia that was displacing the leftabducens nerve within the prepontine cistern. The patientwas given a patch to relieve his diplopia, and a neurologyconsult was obtained. At the 2-month follow-up visit thepalsy had almost completely resolved.Conclusion: Isolated abducens palsies are commonly attrib-uted to a vasculopathic origin in the aging adult; however,in certain instances a compressive intracranial vessel abnor-mality such as vertebrobasilar dolichoectasia may contrib-ute to the underlying etiology.

Poster 73

Repeatability of Home Tonometry Can Be ImprovedWith Increased TrainingPinakin Gunvant, Optom Ph.D., B.S.,Felicia Jackson, B.S., Erin Hocking, B.S., andDaniel Taylor, O.D., Southern College of Optometry,1245 Madison Avenue, Memphis, Tennessee 38104

Background: The Proview Eye Pressure Monitor (Bausch &Lomb, Inc., Rochester, New York) is a pressure phosphenetonometer (PPT) and is reported to be easy to use as a homeocular pressure monitoring device. Home tonometry is im-portant as it gives an estimate of IOP between office visits,which can be useful in management of glaucoma. The PPThas been compared with the gold standard, the Goldmannapplanation tonometer, in various studies, which haveshown anywhere from poor to excellent agreement in mea-suring IOP. The technique used to measure IOP differs inthese devices and thus the measured IOP is likely to vary.The purpose of this study was to evaluate how the PPTcompares against itself and if its repeatability can be im-proved with increased training and home use.Methods: A group of ocular healthy individuals (n�78)were shown a video explaining the procedure for perform-ing the IOP measurements with PPT and performed practicemeasurements using the PPT. The subjects were trained by2 experienced observers (F.J. and E.H.). The subjects werethen asked to perform 2 sets of 3 measurements with 2-minute

331Poster Presentations