RETINAL OXIMETRY IS ALTERED IN EYES WITH CHOROIDAL MELANOMA BUT NOT IN EYES WITH CHOROIDAL NEVI

Purpose: To compare retinal vessel oxygenation in eyes with an untreated choroidal nevus or choroidal melanoma. Methods: The affected and fellow eye of patients with an untreated choroidal nevus (n = 42) or choroidal melanoma (n = 45) were investigated using noninvasive retinal oximetry (Oxymap T1). Oxygen saturation of arterioles (ArtSat) and venules (VenSat) was determined, together with the arteriovenous difference (AV-difference). Results: In choroidal nevus patients, retinal oximetry did not differ between the affected and fellow eye: the mean ArtSat was 94.5% and 94.2% (P = 0.56), the VenSat was 60.5% and 61.3% (P = 0.35), and the AV-difference was 34.0% and 32.9% (P = 0.18), respectively. In choroidal melanoma patients, alterations were detected: the mean ArtSat was 94.8% and 93.2% (P = 0.006), the VenSat was 58.0% and 60.0% (P = 0.014), and the AV-difference was 36.8% and 33.2% (P < 0.001), respectively. The largest increase in AV-difference was observed between the retinal halves without the lesion in melanoma eyes compared with the corresponding half in the fellow eye (37.5% vs. 32.1%, P < 0.001). Conclusion: Although retinal oximetry was not significantly altered in eyes with a choroidal nevus, eyes with choroidal melanoma showed an increased ArtSat and decreased VenSat, leading to an increased AV-difference. These changes may be caused by inflammation and a higher metabolism, with larger oxygen consumption, leading to altered blood flow and intraocular oxygen relocation.