Histological changes in the intraocular structures of rabbit eyes after diode transscleral cyclophotocoagulation

Abstract

Introduction. Currently, the issue of choosing the energy characteristics of laser radiation to ensure the optimal effect on the structures of the ciliary body during diode (810 nm) transscleral cyclophotocoagulation (TSC CPC) remains debatable. Purpose. To determine the histopathological changes occurring in the sclera and ciliary body after transscleral diode cyclophotocoagulation with different energy characteristics of laser radiation in the experiment. Material and methods. The study was conducted on the eyes of 2 rabbits (4 eyes). TSC CPC was carried out using a diode laser with a wavelength of 810 nm and a contact fibre-optic G-probe. Two energy regimes were used: 1 - power 2000 mW, exposure 1.5 s (3 J energy per pulse) and 2 - power 1000 mW, exposure 1.5 s (1.5 J energy per pulse). The study of results of experimental studies included light microscopy of histological sections on the 10th day after TSC CPC. Results. After 2000 mW/1,5 s TSC CPC (energy 3 J) per pulse, pronounced destruction of ciliary processes and underlying stroma of the ciliary body, as well as pigmented and non-pigmented ciliary epithelium, was observed. The coagulation necrosis of collagen fibres of the sclera was detected. After 1000 mW/1,5 s TSC CPC (energy 1.5 J) per pulse, the destruction of the pigmented and non-pigmented epithelium of the ciliary body was observed, with less disorganization the stroma of the ciliary body. The sclera was not affected when the energy was reduced. Conclusion. Diode TSC CPC (810 nm) with a laser radiation power of 1000 mW (exposure 1.5 s) is a more selective form of cyclophotocoagulation, which leads to less destruction of the ciliary body and sclera and at the same time ensures damage to the epithelium of the ciliary body, compared to the use of laser radiation with 2000 mW power.