Comparison of the effects of brimonidine 0.2% and timolol 0.5% on retinal nerve fiber layer thickness in ocular hypertensive patients: a prospective, unmasked study.

AIMS

The aim of this study was to compare the effects of brimonidine and timolol on retinal nerve fiber layer (RNFL) thickness in ocular hypertensive patients.

METHODS

This was a prospective, comparative, and unmasked study. For 12 months, 38 eyes of 19 patients with primary open-angle glaucoma received brimonidine tartrate 0.2%, and 40 eyes of 20 patients received timolol maleate 0.5%. Intraocular pressure (IOP) was measured every 2 months, and RNFL thickness was assessed using Scanning laser polarimetry (GDx) at baseline and at 12 months.

RESULTS

Mean IOP reduction was similar in both groups. Within each treatment group, the RNFL thickness for ellipse average (P = 0.004), superior (P = 0.035), temporal (P = 0.003), inferior (P < 0.0001), and nasal averages (P = 0.044) were significantly decreased from baseline in timolol at 12 months. However, the RNFL thickness for ellipse average and four quadrants showed no significant change from baseline in brimonidine. The between-group difference in RNFL change showed a significant reduction for ellipse average (P = 0.02), temporal (P = 0.005), and inferior averages (P = 0.016) following timolol therapy, as compared to brimonidine.

CONCLUSIONS

There appear to be less progression for RNFL damage following brimonidine 0.2% therapy compared to timolol 0.5% in ocular hypertensive patients over 1 year. This finding does not correlate with IOP reduction.