[The characteristic of vernier acuity on retrobulbar neuritis patients].
PURPOSE: To investigate the clinical characteristic of vernier acuity in retrobulbar neuritis patients. METHODS: The vernier acuity test soft wear system was developed to detect the 15 cases (25 eyes) with retrobulbar neuritis patients. There were 8 eyes of 6 cases with acute retrobulbar neuritis and 17 eyes of 9 cases with chronic retrobulbar neuritis. Subjects' age ranged from 11 to 58 (mean = 25.87). There were 14 eyes of 7 cases male and 11 eyes of 8 cases female. The best visual acuity ranged from 0.05 to 0.7. Two fixed targets and a movable target are shown on the computer screen. The examine was asked to adjust the position of the central target and the relationship between it and align them by using a track-ball. The computer automatically records the deviations of distances between the movable target and the specific one, and computes the average threshold and its variance. RESULTS: There was significant statistical difference in the vernier threshold and its variance between the normal subjects and patients with retrobulbar neuritis in acute stage or convalescence. The correlation coefficient between visual acuity and vernier acuity threshold was -0.88 in the patients with retrobulbar neuritis in acute stage of neuritis (P < 0.01). The correlation coefficient between visual acuity and threshold variance was -0.46(P < 0.05). In convalescence, with an improvement of the disease and the increase of visual acuity, the vernier acuity threshold decreased and the threshold variance reduced. The difference of threshold and its variance between acute stage and convalescence had statistical signification (P < 0.01). The correlation coefficients between visual acuity and vernier acuity threshold was -0.93 in convalescence (P < 0.01). The correlation coefficients between visual acuity and vernier threshold variance was -0.84(P < 0.01) in convalescence. No significant statistical difference was found in the correlation between the vernier threshold in acute stage and in convalescence (P = 0.261). No significant statistical difference was found in the correlation between visual acuity in acute stage and in convalescence (P = 0.11). The correlation coefficients between vernier threshold variance in acute stage and in convalescence was -0.67 (P < 0.01). There was statistical difference among the difference of threshold, visual acuity and standard deviation between acute stage and convalescence respectively (t-test, P < 0.01). CONCLUSIONS: It is suggested that vernier acuity, which changed with the state of the disease, was one of the indexes to evaluate the visual function of patients with retrobulbar neuritis. It could be use as an observation index of supervising the change of patients' visual function and the reaction to medication and guiding medication.