Changes in temperature inside an optomechanical model of the human eye during emulated transscleral cyclophotocoagulation

Abstract

Currently, many diseases of the eye are treated by laser surgery. An understanding of light propagation and the heating of eye tissue during laser exposure is crucial to improving the outcome of these procedures. Here, we present the development of physical and computational models of the human eye by combining optical light propagation and thermal characteristics. For the physical model, all parts of the eye, including cornea, lens, ciliary body, sclera, aqueous and vitreous humors, and iris, were fabricated using a 3D printed holder and modified polydimethylsiloxane. We also present a computational model based on finite element analysis that allows for a direct comparison between the simulation and experimental measurements. These models provide an opportunity to directly assess the rise in temperature in all eye tissues. The simulated and physical models showed good agreement for the transmission of light at varying incident angles. The heating of optical components was investigated in the retina and the ciliary body during simulated laser surgery. Temperature increases of 45.3°C and 30.6°C in the retina and ciliary bodies, respectively, were found in the physical model after 1 minute of exposure to 186 mW of 850 nm laser radiation. This compared to 29.8°C and 33.9°C increases seen under the same conditions in the simulation model with human eye parameters and 48.1°C and 28.7°C for physical model parameters. These results and these models are very promising for further investigation of the impact of laser surgery.

Changes After a Month Following Micropulse Cyclophotocoagulation in Normal Porcine Eyes

“…Because TSCPC can cause thermal transfer from the sclera to the retina, its effect might be greater with higher energy levels, which leads to retinal thinning. 23 , 24 Therefore, our histologic studies revealed that MP-TSCPC directly affects the uvea, but indirectly affects the retina.…”

Opto-Mechanical Eye Models, a Review on Human Vision Applications and Perspectives for Use in Industry

“…Other non-optical modalities, such as ultrasound measurements (Ref. [ 52 ] reported ultrasound biomicroscopy for device characterization, and a dummy eye model for ultrasound biometry is commercially available at [ 90 ]), thermal measurements [ 70 ], or mechanical and structural characterizations [ 55 ], will not be considered in this review, unless the model itself presents relevant features related to optical measurements. Table 3 organizes the main modalities of the respective devices mentioned in this review.…”

“…Table 3 organizes the main modalities of the respective devices mentioned in this review. Some devices are “multi-modal”, and more than one measurement modality was reported in the respective publications [ 28 , 35 , 37 , 41 , 42 , 48 , 52 , 55 , 64 , 70 , 72 , 80 ].…”

“…Regal et al [ 70 ] developed an optomechanical eye model phantom by combining optical light propagation and thermal characteristics, to provide a system for accurately modeling the effects of laser surgery. This model was mainly composed of a main body and ancillary optical components, and a tunable microfluidic iris, and was fabricated using a 3D printed holder and modified polydimethylsiloxane.…”

“…Finally, as stated before, Regal et al [ 70 ] also performed thermal measurements with their eye model. This was done using an 850 nm continuous wave infrared laser diode and a thermal camera installed on the test bench, pointing to the back of the physical model.…”