PMMA Intraocular Lenses Changes after Treatment with Nd:Yag Laser: A Scanning Electron Microscopy and X-ray Spectrometry Study

Abstract

Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser may cause intraocular lenses (IOLs) damages. Therefore, the effects of Nd:YAG laser on IOLs were evaluated. Twenty-four IOLs (copolymer of 2-hydroxyethylmethacrylate and 2-ethoxyethylmethacrylate) were used. For scanning electron microscope (SEM), twelve IOLs were divided into three groups: Group 1, controls; Group 2, IOLs treated with two laser spots (YC-1800 Nidek Nd:YAG laser set at 1.2 mJ); and Group 3, IOLs treated with six laser spots. All IOLs were critical point dried in CO2 and viewed in a Zeiss EVO LS10 SEM. For Energy Dispersive X-ray spectrometry (EDX), four IOLs of each group were examined with a Jeol JMC-6000 SEM. With SEM, Group 1 IOLs showed well-preserved size, shape and surface. Group 2 IOLs exhibited normal shape and margins, a peripheral furrow with irregular blebs, straight clefts and holes on the wrinkled surface. Group 3 IOLs were swollen and broken into two or three parts. With SEM and EDX, Group 1 and the undamaged surfaces of Groups 2 and 3 showed evident carbon and oxygen peaks, while, in the damaged areas, both atoms were significantly reduced. Nd:YAG laser induced evident changes in IOLs morphology and organic alterations in their chemistry: great care during posterior capsule opacification treatment is required.