Effect of Short-Term Oral Valproic Acid on Vision and Visual Field in Retinitis Pigmentosa

INTRODUCTION The aim of this study was to evaluate the effect of short-term oral valproic acid (VPA) on the vision and visual fields of patients with retinitis pigmentosa (RP). METHODS In this prospective, nonrandomized trial, 10 patients (20 eyes) with established RP were treated with oral VPA 500 mg/day for 3 months. Visual acuity was monitored using the Snellen chart and values were converted into Early Treatment Diabetic Retinopathy Study chart and logarithm of the minimum angle of resolution (logMAR) equivalents. Visual field changes were evaluated using the Humphrey visual field analyzer (30-2 SITA standard test protocol). RESULTS Mean visual acuity was significantly improved from a pretreatment value of 20/72 (logMAR 0.560 ± 0.488) to 20/65 (logMAR 0.513 ± 0.422) after 3 months of treatment (P = 0.006). Vision improved by at least one line or more than one line in 10 eyes, and remained stable in the other 10 eyes. Visual field improvement was noted in nine eyes (P < 0.05, χ(2) test), nine showing no significant field change and in two visual fields could not be recorded due to poor vision. CONCLUSION Short-term (3-month) treatment with VPA improves the vision and visual field of patients with RP.