Solar maculopathy Solar burn, Phototoxic maculopathy, Eclipse blindness, Foveomacular retinitis

Description assessment of damage to the individual Solar maculopathy is a degeneration of layers of the retina and RPE over time. the macula associated with phototoxic- Initially, the retinal layers show increased ity ‘excessive light’. It is considered to reflectivity, with changes to the RPE and particularly result from photochemical choroid appearing one to two weeks damage to the retina associated with later. In the chronic condition, months ultraviolet (UV) radiation from the sun, to years later, a lamellar retinal hole is although thermal effects associated with usually evident corresponding to the longer wavelengths may play an additive damaged photoreceptors and RPE. The role. Damage to the retina and retinal overlying neurosensory retina is attenu- pigment epithelium (RPE) from the sun ated and thinned. The vitreoretinal inter- is dependent upon the time of exposure, face will be normal. solar factors including the position in the sky and ocular factors including Advice the crystalline lens spectral absorbance Prevention is the preferable treatment and the individual level of pigmenta- for solar maculopathy, since there is tion. There is usually intense bleaching no specific treatment once damage has and shedding of photoreceptor outer occurred. Patients and the public may segments and loss of RPE function. RPE pigmentation effects are varia- Figure 1 benefit from health education programs Other phototoxic maculopathies have ble, ranging from de-pigmentation to Central solar regarding sun-gazing, particularly prior also been reported: hyper-pigmentation or RPE hyper- maculopathy, to a solar eclipse or in areas with a reduced ● Ophthalmic instruments or the operat- plasia. Classically, the chronic lesion is several ozone layer. ing room lamp, if ultraviolet radiation is described as reddish with sharply demar- weeks after not filtered out cated edges, somewhat like a stage 1A exposure. Prognosis ● Welder’s maculopathy can occur, macular hole. The image Generally, retinal tissue damage due to usually accompanied by the more shows loss of solar maculopathy is reversible to some common photokeratitis. If severe, a PREVALENCE some central extent, with improvement in acuity macular hole may form The condition is rare (approximately neural occurring within two to four weeks of ● Laser exposure. The type of retinal 1/10,000) and mainly reported in at risk elements exposure. Some patients experience a damage depends upon the wavelength groups: Military personnel, sun bathers, and retinal small persistent scotoma despite restora- of light, exposure time and power level. religious sun gazers, solar eclipse viewers pigment tion of normal acuity. If there has been A laser (thermal) burn such as from and users of psychotropic drugs. epithelium extensive damage to the photoreceptors krypton or argon laser is seen almost and and the RPE (initial acuity 20/200 or immediately, unlike a phototoxic burn. Significance surrounding worse), there may be localised retinal Solar maculopathy is a preventable cause pigmentary atrophy and degeneration, with less Symptoms of visual loss. changes favourable visual prognosis. There is usually a history of solar exposure or viewing an eclipse. Typically, DiffERENTIAL Diagnosis symptoms first occur several hours after Macular hole (Stage 1), central serous The full series of these articles is available in the book exposure. There may be complaints of chorioretinopathy, macular oedema, age- Posterior Eye Disease and Glaucoma A-Z by Bruce AS, blurred vision, central or paracentral related macular degeneration. O’Day J, McKay D and Swann P. £39.99. For further scotomata, metamorphopsia, chromat- information click on the Bookstore at opticianonline.net opsia or headache. See also Stargardt’s disease, Cone dystrophy. ● Adrian Bruce is a Chief Optometrist at the Victorian Signs College of Optometry and a Senior Fellow, Department Vision may be decreased to 20/40 or Management of Optometry and Vision Sciences, The University of even 20/100, often bilaterally. A solar Melbourne. maculopathy is usually less than 0.2mm Additional investigations ● Justin O’Day is an Associate Professor in the in diameter, corresponding to the size of Amsler grid will often demon- Department of Ophthalmology, The University of the retinal image of the sun. First signs strate central or paracentral distor- Melbourne and Head Of Neuro-Ophthalmology Clinic, of phototoxicity occur in the first one to tion (metamorphopsia). Fluorescein Royal Victorian Eye and Ear Hospital. two days, with a small yellowish foveal angiogram may show a small window ● Daniel McKay is a Medical Officer at the Royal or parafoveal lesion and mild pigmen- defect or be normal. There may be Victorian Eye & Ear Hospital. tary changes and retinal oedema. The chronic decompensation of the blood ● Peter Swann is Associate Professor in the School of yellow spots are intraretinal, presumed retinal barrier. Optometry, Queensland University of Technology. to be xanthophyll pigment. Chronic Ocular coherence tomography enables opticianonline.net 25.07.08 | Optician | 51