The impact of additional laser photocoagulation on PRP evaluated by the simulation based on photoreceptor densities

Abstract

Purpose : One of the aims of panretinal laser photocoagulation (PRP) is the destruction of tissues with high oxygen consumption such as photoreceptors. In such procedures, the effect of retinal photocoagulation, which is performed in the same photocoagulated area, may change if it is applied to different locations with different photoreceptor densities. Thus, we evaluated the impact of additional laser photocoagulation on PRP by the simulation based on photoreceptor densities.

Methods : We constructed a three-dimensional (3D) average distribution of photoreceptors with 3D computer-aided design (CAD) software using previously derived photoreceptor density data, and calculated the number of photoreceptors destroyed by additional PRP from equator to peripheral (A), one additional row of photocoagulation inside the vascular arcade (B) and photocoagulation in temporal area from vascular arcade to equator (C) (size 400 µm on the retina, spacing 1.0 spot) using a geometry-based simulation. We calculated the ratio of the number of photoreceptors destroyed to the total number of photoreceptors, termed the photoreceptor destruction index, to investigate the impact of photoreceptor densities on PRP.

Results : In this 3D simulation, the total number of photoreceptors was 96,571,900. The respective total numbers of photoreceptors destroyed by each condition were 3,542,400 (A), 2,206,400 (B) and 525,300 (C) and the respective photoreceptor destruction indexes were 3.6% (A), 2.28% (B) and 0.54% (C).

Conclusions : The impact of additional laser photocoagulation on PRP could be evaluated by photoreceptor destruction indexes.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.