Differentiating Patients with Glaucoma from Glaucoma Suspects by Retinal Nerve Fiber Layer Assessment Using Nerve Fiber Analyzer

PURPOSE: To evaluate the difference of retinal nerve fiber layer measurements as obtained by Nerve Fiber Analyser according to visual field defects in subjects with large Cup-to-Disc ratio (C/D ratio>or=0.6) and to determine which predictable parameters are useful in glaucoma diagnosis. METHODS: Fifty one normal subjects, 17 patients with glaucoma, 18 glaucoma suspects based on optic disc appearance and visual field defect participated. Nerve fiber layer thickness assessments using scanning laser polarimeter (Nerve Fiber Analyzer II software version 2.1.; Laser Diagnostic Technologies, Inc., San Diego, California, U.S.A.) were measured in normal subjects, patients with glaucoma, and glaucoma suspects. Measured nerve fiber layer thickness parameters were compared each other. RESULTS: Superior to inferior ratio (S/I ratio) was only statistically significant parameter to differentiate glaucoma from glaucoma suspects having glaucomatous optic nerve head. CONCLUSIONS: Superior to inferior ratio (S/I ratio) is useful parameter to predict differentiating patients with glaucoma from glaucoma suspects.

The Effect of Myopic Refractive Error on the Evaluation of Optic Nerve Head Parameters using Topog raphic Scanning System

This study was performed to determine the effect of myopic refractive error on optic nerve head parameters using Topographic Scanning System (TopSSTM). One hundred thirty two myopic eyes of 120 subjects with normal visual fields were enrolled in this study.Their visual acuities were better than 0.8 with their corrections.Subjects were divided into four myopic groups.Mean refractive error was -3.8 diopter (range:+1.25D ~-1 2.2 5 D ). Total contour area, effective area, volume above, neuro-retinal rim area, and contour variation showed statistically significant correlations with myopic refractive error.The disc area (total contour area)was correlated with the myopic refractive error.However, effective area, volume above, and neuro-retinal rim area showed statisticall correlation with total contour area rather than myopic refractive error.Contour variation was correlated with myopic refractive error.With increased disc contour tilt, nasal and superior neuroretinal rim area also statistically increased. In conclusion, effect of disc area and contour variation should be considered in the evaluation of optic nerve head parameters of myopic patients. However, further evaluation of myopic patients with glaucoma is required through comparison study with control group.

Comparison of Stere oacuity between Crossed and Uncrossed Disparities in Dynamic Stereoacuity

Demonstration of an overall superiority in the accuracy of discriminating crossed-disparity targets should be noted as opposed to uncrossed-disparity targets.We investigated the difference in stereoacuity between crossed and uncrossed disparities using dynamic stereoacuity and superiority of crossed disparity stereopsis.We examined dynamic stereoacuity in 73 normal subjects at 120 cm test distance and 96 subjects at 150 cm test distance.At 120cm test distance, the mean dynamic stereoacuity of crossed disparity was 313.4 +/-261.4 (mean +/-standard deviation)sec of arc, and, the mean dynamic stereoacuity of uncrossed disparity was 343.1 +/-261.4 sec of arc.At 150 cm test distance, the mean dynamic stereoacuity of crossed disparity was 263.2+/-196.8 sec of arc, and, the mean dynamic stereoacuity of uncrossed disparity was 310.6 +/-310.6 sec of arc.Statistical significance shows a higher stereoacuity of crossed disparity than uncrossed disparity in both test distance (Wilcoxon matched pairs signed ranks test, p<0.05).