Foveal light exposure is increased at the time of removal of silicone oil with the potential for phototoxicity

Abstract

Foveal light exposure, and therefore the potential for phototoxicity, is transiently increased at the time of removal of silicone oil. This is due to uneven macular illumination resulting from the optical vignetting effect of different silicone oil bubble sizes. The increase in foveal light exposure may be significant when the procedure is performed under bright operating microscope light on already stressed photoreceptors of an eye filled with silicon oil. We advocate the use of precautions, such as central shadow filter on the operating microscope light source to reduce foveal light exposure and the risk of phototoxicity at the time of removal of silicone oil. The graphic ray tracing computer program used in this study shows promise in eye modeling for future studies.

Vision loss under silicone oil tamponade

“…Enhanced phototoxicity, especially at the time of silicone oil removal, is a different discussed mechanism of vision loss [34]. Since all of our patients experience vision loss before oil removal, we do not support this theory.…”

Un-explained visual loss following silicone oil removal: results of the Pan American Collaborative Retina Study (PACORES) Group

“…The incidence of this phenomenon has been reported to be anywhere from 1–30% [18, 29–31]. In the largest series to date, Moya and collaborators [21] found that 14 of 421 (3.3%) eyes that underwent silicone oil removal developed un-explained visual loss.…”

The incidence of unexplained visual loss following removal of silicone oil

“…Several hypotheses have been proposed including sudden changes in potassium concentration in retro-oil fluid that may lead to macular dysfunction due to photoreceptor apoptosis on oil removal, 18,20 photo-toxicity at the time of silicone oil removal, 15,21,22 and fibrogenic growth factor disturbances. 23 Of the 14 patients who had at least two SL reduction in visual acuity in our study this appeared to happen at the time of oil removal.…”