Effect of Laser Wavelength on Delivering Appropriate Laser Burns through the Opaque Lens Using a Pattern Scan Laser

Abstract

Background/Aims: We evaluated the effects of pattern scan laser (PSL) wavelength in delivering appropriate laser burns to the retina of eyes with an opaque lens. Methods: Sixteen shots of 2 × 2 square grids (64 laser spots) were delivered using green (532-nm), yellow (577-nm) and red (647-nm) lasers to the retinas of mice with mild cataract induced by chloral hydrate (400 mg/kg). Three eyes with clear lenses served as controls. One week after laser coagulation, the ratio of appropriate burns, defined as coagulation restricted to the outer half of the retina without retinal or choroidal hemorrhage, was investigated histologically. Results: With the green laser, we confirmed only 3.0 ± 2.0 appropriate burns in eyes with an opaque lens, in contrast to 13.7 ± 4.0 effective burns in eyes with a clear lens. On the other hand, the yellow and red lasers produced 18 ± 5.2 and 13 ± 1.5 appropriate burns, respectively, in eyes with an opaque lens. Conclusion: Although all three PSL wavelengths successfully delivered appropriate burns restricted to the outer half of the retina in eyes with an opaque lens, the longer-wavelength yellow and red lasers were significantly more effective than the green laser. PSL may be a treatment option to accompany anti-vascular endothelial growth factor drug therapy.