[Effect of topical glaucoma medications on optic disc topography in normal tension glaucoma].

PURPOSE

To investigate the effects of topical glaucoma medications on optic disc topography in patients with normal tension glaucoma (NTG) using confocal scanning laser ophthalmoscopy.

SUBJECTS AND METHODS

We enrolled 39 NTG patients (39 eyes) who had not been treated for glaucoma. A combined medication of 0.005% latanoprost and 0.5% timolol gel was administered. Optic disc parameters were measured before and after the treatment using the Heidelberg Retina Tomograph (HRT). The treatment period was 20.2 +/- 6.4 days (mean +/- SD).

RESULTS

Administration of these two drugs significantly decreased the intraocular pressure (IOP) from 16.7 +/- 1.9 mmHg to 12.3 +/- 1.9 mmHg (26.7 +/- 8.7% decrease). Cup area, cup/disk area ratio and cup volume decreased significantly, while the rim area increased significantly. Linear progression analysis showed a significant correlation between the percent decrease in the IOP and the topographic changes in the cup area, cup/disk area ratio, rim area, cup volume, rim volume, and height variation contour. When the subjects were divided into two groups: patients with high baseline IOP of more than 16 mmHg (HNTG group) and those with low baseline IOP below 15 mmHg (LNTG group), significant changes in several parameters were observed only in the HNTG group.

CONCLUSIONS

These results suggest that the topographic changes in the optic disc were induced by the short-term topical glaucoma medications prescribed for the NTG patients, and the changes in several HRT parameters correlated with the percent decrease in the IOP.