A Calculation of the Effect on Aphakic Hazard Function by Spectrally Modifying Various Ophthalmic Illumination Sources

Abstract

Abstract: : Purpose: To evaluate the theoretical retinal hazard for ophthalmic endo-illuminators employing different light sources - Xe short arc, Metal-Halide arc and Tungsten Halogen lamps. Methods: The Aphakic Hazard Function was calculated based on the spectra from the above-mentioned sources according to function defined within International Standard ISO 15752: 2000(E) "Ophthalmic Instruments - Endoilluminators - Fundamental Requirements and Test Methods for Optical Radiation Safety". Various UV-Blue wavelength blocking filters were then applied to evaluate their relative effect on the function. Results: We measured the spectra for a number of commercially available ophthalmic endoilluminators. We demonstrate that unaltered spectra from Xe and Metal-Halide sources significantly increase the Aphakic Hazard Function as compared to tungsten Halogen sources. However, commercially available integrated UV-Blue blocking filters mitigate the hazard to varying degrees. The standard recommends that the energy in the range of the spectrum below 420nm be attenuated as much as possible. Conclusions: UV-Blue wavelength blocking filters significantly lower the theoretical Aphakic Retinal Hazard. The use and specification of these filters is particularly critical for the short-arc Xe and Metal-Halide sources.

Keywords: radiation damage: light/UV • vitreoretinal surgery • computational modeling