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Machines and Instrumentation
Published in Pradeep Venkatesh, Handbook of Vitreoretinal Surgery, 2023
Photic retinopathy results from the toxic effects of photochemical, photothermal, and mechanical interaction between light and retinal tissue. Tso first reported the possibility of retinal phototoxicity from artificial light under experimental conditions in rhesus monkey eyes in 1973. Subsequently, several other reports appeared following cataract extraction, epikeratophakia, triple procedure, vitreous surgery, Molteno implant, and pterygium surgery. The actual incidence from operating microscope–induced macular phototoxicity remains poorly defined with estimates ranging from 3% to 28%. The main sources of retinal phototoxicity during vitreoretinal surgery are indirect ophthalmoscope, operating microscope, and endoilluminator probes. Recognized time thresholds beyond which photic retinopathy could occur are 4.0 to 7.5 minutes for a 30W operating microscope and 15 minutes for the indirect ophthalmoscope. For endoilluminators, it depends on the light source, distance from the retina, diameter, and divergence of the beam. The shape and size depend on the light source. Operating light–induced lesions are sharply defined and are rarely more than 1–2 disc areas, while endoilluminator lesions are larger and have less distinct margins. The location of the lesion in operation microscope–induced photic maculopathy is typically superior or inferior to the fovea. This is determined by the effect of the bridle suture and because the coaxial light is normally 1.5–6 degrees off normal. Because phototoxicity has a cumulative effect, reducing surgical time under the microscope and endoilluminator would reduce the risk of this ‘invisible’ and delayed complication.
‘Poppers Maculopathy’ and the adverse ophthalmic outcomes from the recreational use of alkyl nitrate inhalants: a systematic review
Published in Seminars in Ophthalmology, 2023
Caleb Bartolo, Konstandina Koklanis, Meri Vukicevic
Reports have shown that solar (photic) retinopathy may be considered as a differential diagnosis for poppers maculopathy as it presents with similar anatomical changes and clinical characteristics.20,40,41,45 Patients with solar (photic) retinopathy may experience VA defects secondary to sub-foveal retinal pigment epithelium and outer segment disruption seen on SD-OCT and central yellow foveal dots observed on fundoscopy. An accurate diagnosis of the maculopathy follows a succinct patient history of excessive sun gazing or eclipse viewing.55 Interestingly, Fajgenbaum56 suggested that recreational users of poppers in nightclub settings may be susceptible to excessive light gazing and emphasised the importance of focussed questioning when obtaining a patient history to assist in determining whether this influences pathology and for differential diagnosis.