Normative database of retinal oximetry in Asian Indian eyes

Abstract

Objective: To study the oxygen saturation profile in normal Asian Indian eyes. Design: A cross sectional prospective study. Subjects: Ninety eight consecutive patients presenting to our hospital with best corrected distance visual acuity (BCVA) of 20/20 and a normal ophthalmic examination were included in the study. Patients having any ocular or systemic disease were excluded from the study. Materials and Methods: Oximetry was performed on all subjects with the Oxymap T1 retinal oximeter (Oxymap hf, Reykjavik, Iceland). Main Outcome Measures: The images were analysed for oxygen saturation and diameter. Results: The mean age was 33 years (Range: 18-63; SD: 12.4). The average arteriolar saturation was 90.3 ± 6.6% and the venous saturation was 56.9% ± 6.3. The average A-V (arterio-venous) difference was 33.2% ± 5.2. There was an increase in arteriolar (R 2 = 0.264; p=0.001) and venous saturation (R 2 = 0.151; p=0.001) with age. There was no significant change in the arterio-venous saturation difference (AVSD). The inferotemporal quadrant had the lowest saturations. Age correlated positively with ocular perfusion pressure (OPP)(R 2 = 0.07; p=0.007). OPP correlated positively with global arteriolar saturation (R 2 =0.057, p=0.018). Conclusion: This study provides the normative database for an Indian population and is comparable to previous studies. Age, vessel diameter and OPP were the significant factors that influenced the saturation. Arteriolar and venous saturations increased with age while the AVSD did not change significantly.