Retinal thickness and visual thresholds measured in patients with retinitis pigmentosa

PURPOSE:: To determine the association between retinal thickness and visual function in patients with retinitis pigmentosa (RP). METHODS:: Retinal thickness was estimated from optical coherence tomography (OCT) images obtained for six patients with RP. The thickness measurements were compared with dark-adapted rod and minimally light-adapted cone thresholds obtained by psychophysical testing using a Tübinger perimeter and with standard light-adapted Humphrey visual field (HVF) perimetric thresholds. RESULTS:: Four patterns of association between retinal thickness and visual function were observed: normal retinal thickness and normal visual thresholds; normal retinal thickness and normal cone thresholds but elevated rod thresholds; reduced retinal thickness and elevated rod and cone thresholds; and normal retinal thickness and normal Humphrey thresholds but elevated rod and cone thresholds by Tübinger perimetry. CONCLUSION:: Retinal thinning was observed only when both rod and cone thresholds were elevated. However, normal retinal thickness was not necessarily accompanied by normal visual sensitivity. The determination of retinal thickness by OCT and its association with psychophysical measurements of visual function could be useful for identifying those RP patients who might respond most optimally to therapeutic interventions.