980 nm Diode laser retinochoroidal photocoagulation – in vitro comparison with frequency doubled Nd:YAG (532 nm) laser

Abstract Purpose: To evaluate acute effects of diode laser (980 nm) on retina and choroid and to compare these effects with the effects of frequency doubled Nd:YAG laser (532 nm) on same eye structures. Methods: Freshly enucleated pig's eyes were treated with diode laser (980 nm) and frequency doubled Nd:YAG (532 nm) through the slit lamp adaptors. Same energy densities were used. Histological examination of the treated eyes was performed after photocoagulation. Results: Changes in photoreceptor layer (slightly increased eosinophilia) and outer nuclear layer (slightly condensed nuclear chromatin) of retina and coagulation necrosis of choroid were present in all laser lesions. There were no significant differences in retinal changes produced by both lasers. Coagulation necrosis of choroid was more pronounced in lesions produced by 980 nm diode laser. Conclusions: Acute effects of both lasers were similar, although thermal damage produced by 980 nm diode laser extended deeper. The 980 nm diode laser could be used for retinochoroidal photocoagulation.