A pilot study of topical treatment with an alpha2-agonist in patients with retinal dystrophies.

PURPOSE

The aim of this study was to assess the neuroprotective effect of a topical alpha2-agonist in patients with retinal dystrophies.

METHODS

This study was a prospective, placebo-controlled, double-masked, randomized clinical trial. A total of 26 patients with retinal dystrophies were included. One (1) randomly selected eye was treated with brimonidine tartrate 0.2% twice-daily, while the fellow eye received artificial tears. Disease progression parameters tested at 6-8-month intervals throughout the study included Goldmann visual fields, contrast sensitivity, color vision, and fullfield electroretinography.

RESULTS

Seventeen (17) of the 26 recruited patients completed the study. Except for 1 patient with an 18-month follow-up, all patients were followed up for 24-36 months (mean, 29). At the conclusion of the study, there were no differences detected in visual acuity, color vision, and contrast sensitivity between the treated and control eyes. There was a trend, however, toward a lesser degree of visual field loss in the brimonidine-treated eyes. There was also a delay in the time required to reach a 25% visual field loss in the treated eyes. These differences were more pronounced in a subgroup of patients diagnosed as retinitis pigmentosa and with visual fields of 5 cm2 or more at baseline.

CONCLUSIONS

The findings of this pilot study suggest a trend for slower progression in the eyes of patients with retinal dystrophy when treated with brimonidine, according to one of the parameters that was studied (visual field loss). Further studies that include a larger number of patients and a longer follow-up period are needed to clarify and confirm the potential neuroprotective effect of alpha2-agonists in human retinal dystrophies.