OPTIMIZATION OF LASER SURGERY OF THE SECONDARY CATARACT

Abstract

Background: This is a theoretical and experimental study of the thermomechanical effects of laser radiation with a wavelength of 1.06 microns on the eye tissues during a laser surgery on the secondary cataract (pupillary membrane). Its relevance is related to the rates of complications after laser surgery of the eye associated with the choice of energy and time parameters of the laser irradiation. These parameters are related to the occurrence of such factors as unstable fields of thermal stress and pressure that are difficult to take into account and indirectly lead to adverse events when removing the secondary cataract. Aim: To minimize side effects and to optimize the existing technology of laser removal of the secondary cataract. Materials and methods: Samples of a normal lens capsule and of lens capsules with various types of opacities taken during a cataract surgery, with various optic characteristics and thickness, were treated with an infrared laser (Nd:YAG laser, 1064 nm). We performed morphometric measurements and built up a theoretical model of the processes in a continuous medium under the effects of impulse laser irradiation. Results: The results of numerical modelling with this newly developed theoretical model are in satisfactory agreement with the experimental data on development of deformities obtained with the autopsy materials (posterior capsule of the human lens with various optical characteristics and thickness, from thin transparent membranes to more thick opaque samples). Conclusion: This study would allow for optimization of the technology of laser treatment for secondary cataracts by changing the irradiation parameters during the procedure.

Keywords

• laser
• secondary cataract
• theoretical model
• thermal stress