Optimization of Transscleral Laser Cyclothermotherapy Method (experimental study)

Objectives: to evaluate the feasibility of reducing exposure time during transscleral laser cyclothermotherapy (TLCTT) by applying a pulsedperiodic laser mode in an experimental setting. 

Methods. The study was conducted on Chinchilla rabbits of both sexes, weighing 1.5–2.0 kg. Animals were divided into two groups. The control group (20 rabbits, 40 eyes) underwent TLCTT using a continuous laser mode (0.3 W, 16 s). The experimental group (10 rabbits, 20 eyes) received TLCTT with a pulsed-periodic laser mode (duty cycle 50 %, pulse period 1 s), at 0.6 W for 8 s. Biomicroscopy was performed one day after the procedure to evaluate inflammatory response, and macroscopic examination of ciliary body specimens was carried out to assess the characteristics of destruction foci. 

Results. Biomicroscopy revealed mixed conjunctival injection in all animals, with moderate chemosis in 45 % of eyes in the control group and 50 % in the experimental group. Aqueous humor opalescence of moderate intensity was noted in 75 % and 80 % of eyes, respectively. No precipitates, posterior synechiae, or fibrinous deposits were observed. Macroscopically, destruction foci appeared as pale areas of ciliary processes with comparable diameters (1.35 ± 0.07 mm in the control group and 1.34 ± 0.08 mm in the experimental group, p = 0.3). No rupture-associated mechanical effects were detected in either group. 

Conclusion. The pulsed-periodic laser mode achieved destruction foci of comparable size to conventional TLCTT, without inducing additional mechanical damage or excessive postoperative inflammation. The shortened exposure time reduces the risk of light guide displacement during the procedure, potentially improving both safety and effectiveness.

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