Sudden severe visual loss associated with peripapillary burns during panretinal argon photocoagulation.

A 31-year-old woman lost central visual acuity in her left eye during scatter argon laser photocoagulation when her ophthalmologist treated the temporal peripapillary region. There was no evidence for a vascular explanation. Previous experimental work showed that the lateral spread of thermal energy into the optic nerve parenchyma from the peripapillary pigment epithelium and choroid can destroy adjacent nerve fibres. There is a risk of thermal optic neuropathy caused by peripapillary photocoagulation.