Abstract
Abstract: :
Purpose: To determine the relationships of visual acuity to central retinal thickness and structure and to quantify the intervisit reproducibility of central retinal thickness measurements in patients with retinitis pigmentosa. Methods: We studied 162 patients (91 males and 71 females, ages 18 to 68 years) with the typical forms of retinitis pigmentosa who had Snellen visual acuities ranging from 20/20 to 20/200, minimal to no cataracts, and no visible intraretinal cysts by optical coherence tomography (OCT3). We measured visual acuities with ETDRS acuity charts and used OCT to automatically calculate retinal thickness within the central 1 mm and to rate the photoreceptor inner segment/outer segment (IS/OS) junction in that region. Sixty–three patients who returned within 2 months for repeat OCT provided estimates of retinal thickness intervisit reproducibility. Results: ETDRS acuity was related to central retinal thickness by a second–order polynomial (r2 = 0.40, p < 0.001) that allowed prediction of acuity within 10 letters (0.2 log–unit) in 85% of cases. Controlling for retinal thickness, we found that acuity averaged 53% better with an incomplete IS/OS junction compared with no junction and 20% better with a normal IS/OS junction compared with an incomplete junction. Intervisit reproducibility of central retinal thickness showed 98% confidence limits of ±12 µm. Conclusions: Visual acuity tends to be better in patients with typical retinitis pigmentosa who have a thicker central retina. For the same retinal thickness, acuity is better in patients whose retinas have longer cone outer segments. An increase or decrease of more than 12 µm in central retinal thickness at follow–up is a significant (p < 0.01) change.
Keywords: retinal degenerations: hereditary • retina • clinical (human) or epidemiologic studies: systems/equipment/techniques