[Effects of optic disc size on progression of visual field defects in normal-tension glaucoma].

PURPOSE: To investigate the influence of optic disc area on the progression of visual field (VF) defects in normal-tension glaucoma (NTG). We evaluated the correlation between the right-left differences of the progression of VF defects and those of the intraocular pressure and the ocular anatomical factors. METHODS: Thirty two eyes of 16 NTG patients with a significant difference between the left and right optic disc area, were followed up for more than 5 years after diurnal variation analyzed with Heidelberg Retina Tomograph (HRT), and without myopic disc shape. The left and right eyes of the patients were allocated to two groups, a group with a relatively smaller eye disc and a group with relatively larger eye disc. They were studied regarding the probability of VF stability using the Kaplan-Meier life-table analysis. In addition, a comparison of clinical factors was evaluated between the two groups (Mann-Whitney U test). RESULTS: The probability of VF stability at the 107-month follow-up was 60 +/- 13% (mean +/- SE)in patients with small disc area, and 25 +/- 11% in patients with large disc area. Optic disc area was found to have significant influence on the progression of VF defects (p = 0.022, log-rank test). In clinical factors, no statistically significant difference except disc area was found between the two groups. CONCLUSIONS: These findings suggest that optic disc area is associated with the progression of VF defects in patients with NTG.