Retinal vessel oxygen saturation and vessel diameter in retinitis pigmentosa

Abstract

Purpose To assess retinal vessel oxygen saturation and retinal vessel diameter in retinitis pigmentosa. Methods A retinal oximeter (Oxymap ehf., Reykjavik, Iceland) was used to measure retinal vessel oxygen saturation and vessel diameter in ten patients with retinitis pigmentosa (RP) (mean age 49 years, range 23-71 years). Results were compared with age- and gender-matched healthy individuals. All patients had advanced stage of the disease with visual fields restricted to the macular region. Results Oxygen saturation in retinal venules was 58.0 ± 6.2% in patients with RP and 53.4 ± 4.8% in healthy subjects (p = 0.017). Oxygen saturation in retinal arterioles was not significantly different between groups (p = 0.65). The mean diameter of retinal arterioles was 8.9 ± 1.6 pixels in patients with RP and 11.4 ± 1.2 in healthy controls (p < 0.0001). The corresponding diameters for venules were 10.1 ± 1.2 (RP) and 15.3 ± 1.7 (healthy, p < 0.0001). Conclusions Increased venous saturation and decreased retinal vessel diameter suggest decreased oxygen delivery from the retinal circulation in retinitis pigmentosa. This is probably secondary to tissue atrophy and reduced oxygen consumption. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.