Absorption of short wavelengths of endoillumination in indocyanine green solution: implications for internal limiting membrane removal.

Purpose: To measure the absorption coefficients of short wavelengths, irradiated by a light source used for vitreous surgery, in indocyanine green (ICG) solution and balanced salt solution (BSS), and to determine the implications of these absorption coefficients on retinal phototoxicity caused by ICG-assisted internal limiting membrane removal.

Methods: The absorption coefficients of short wavelengths irradiated by a commercially available light source used for vitreous surgery were measured in ICG solution and BSS using a dual-beam spectroradiometer.

Results: The absorption coefficient of wavelengths irradiated by the endoillumination light source in ICG solution was almost the same as that obtained in BSS. The absorbance coefficients of the ICG solutions were 0.18 cm(-1) at 400 nm and 0.03 cm(-1) at 450 nm. In BSS, the absorption coefficients were 0.17 cm(-1) at 400 nm and 0.015 cm(-1) at 450 nm. No significant difference in absorbance was seen between 400 nm and 450 nm ( P>0.05).

Conclusions: The absorption of wavelengths is not greater in ICG solution than in BSS. ICG solution during intravitreal use probably does not enhance retinal photochemical injury during ICG-assisted internal limiting membrane removal.