The occurrence of retinol and carotenoids in human subretinal fluid

Purpose. To investigate if retinol and carotenoids are present in the subretinal space following rhegmatogenous retinal detachment. Methods. Blood and subretinal fluid were collected from patients at the time of surgical repair of retinal detachment. After removal of cellular contents in a specimen by centrifugation, the supernatant fraction was analyzed by liquid chromatography using a silica column eluted by 16% dioxane in hexane. Retinol and carotenoids were identified in the chromatograms based on their retention time and absorption spectrum. Results. The retinol concentrations (mean ± SD) in the serum and subretinal fluid were 305 ± 144 and 166 ± 96 ng/ml respectively. The 450 nm chromatogram had 7 peaks with the characteristic absorption spectrum of carotenoids. Peak 1 and 7 coincided with the retention time of β-carotene (1.8 min) and lutein (10.8 min) respectively, The concentrations of β-carotene and lutein in serum were 161 ± 63 and 142 ± 98 ng/ml respectively. There was very little β-carotene in subretinal fluid (4.7 ± 2.4 ng/ml). Lutein was the major carotenoid peak in subretinal fluid (41.4 ± 14.1 ng/ml). The minor carotenoid peaks of serum were not observed in subretinal fluid. Conclusion. There is a substantial amount of retinol and lutein in subretinal fluid. The high proportion of lutein and very low amount of β-carotene in the subretinal fluid support the occurrence of a highly selection transport mechanism of lutein from the blood to the retina.