Aqueous flare in retinitis pigmentosa

BACKGROUND: The purpose of this study was to quantify blood-ocular barrier impairment by measuring aqueous flare in retinitis pigmentosa (RP) and to search for clinical correlations. METHODS: Forty-nine patients (94 eyes) with RP and 85 normal controls were examined. Aqueous flare was quantified with the noninvasive laser flare-cell meter (FC-1000, Kowa, Japan). Degrees of cystoid macular edema (CME), vitreous pigment dusting (VPD), intraretinal migration of retinal pigment epithelium, and waxy pallor of the optic nerve head were determined semiquantitatively by biomicroscopy. Data were analyzed using the t-test the Mann-Whitney U-test, the chi-squared test and regression analysis by taking into account the dependency of data from two eyes of the same patients. RESULTS: Aqueous flare (photon counts/ms) was significantly higher in RP (mean 10.11 +/- 3.53) than in normals (3.89 +/- 0.94; P < 0.001). Clinically significant CME was present in 26% of eyes with RP, being significantly more frequent in autosomal dominant RP (11 of 16 eyes, 69%) than in other variants (17%; P < 0.005). Multivariate analysis revealed that CME was most strongly associated with flare values (r = 0.84), P < 0.01), whereas--after adjusting for CME--correlations between aqueous flare and other clinical findings did not reach significance. CONCLUSION: RP eyes show increased aqueous flare values, indicating impairment of blood-occur barriers. This appears to be associated with CME and with autosomal dominant RP.