Phototoxicity From Ophthalmic Instrumentation
The potential for photochemical damage from exposure to modern ophthalmic instruments has been studied extensively. Injuries have been reported from operating microscopes and from fiber-optic endoilluminating probes used in vitrectomies. The incidence of photic retinopathy after contemporary cataract surgery is not known. However, cases continue to be reported after intraocular surgery. The incidence increases with prolonged operating times but can occur even with surgery times as short as 30 minutes. In retinal surgery, photic injury is more likely to occur with prolonged, focal exposure, especially when the light probe is held in close proximity to the retina, as it may be during macular hole and epiretinal membrane procedures.
Most affected patients are asymptomatic, but some will notice a paracentral scotoma on the first postoperative day. Depending on the severity of the damage, vision may return to normal after some time, or it may progressively deteriorate. Acutely affected patients may have a deep, irregular, oval-shaped, yellow-white retinal lesion adjacent to the fovea that resembles the shape of the light source. The lesion typically evolves to become a zone of mottled RPE that transmits background hyperfluorescence on fluorescein angiography.
Reports of photic macular lesions occurring after intraocular surgery underscore the need for prevention. During ocular surgery, the risk of photic retinopathy may be reduced by minimizing exposure time, avoiding the use of intense illumination, using oblique illumination when possible during parts of the surgery, filtering out short-wavelength blue light and UV light, and using shielding. BCSC Section 11, Lens and Cataract, lists several precautions for minimizing retinal light toxicity. See also BCSC Section 3, Clinical Optics.
van den Biesen PR, Berenschot T, Verdaasdonk RM, van Weelden H, van Norren D. Endoillumination during vitrectomy and phototoxicity thresholds. Br J Ophthalmol. 2000; 84(12): 1372–1375.
Youssef PN, Sheibani N, Albert DM. Retinal light toxicity. Eye. 2011;25(1):1–14.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.