PASCAL(PAttern SCAnning Laser) Photocoagulator: Evolution Of Size In Photocoagulation Scars

Abstract

Purpose: : To assess the evolution of photocoagulation scars induced with the PASCAL photocoagulator in diabetic retinopathy.

Methods: : This study included 20 successive patients. Inclusion criteria were patients with diabetic retinopathy requiring panretinal photocoagulation. For each patient, before photocoagulation, we measured: visual acuity, fundus photography, fundus autofluorescense(FAF) and fluorescein angiography. We recorded the following parameters: power, duration, size, pattern and theoretical distance between spots. We completed fundus photography and fundus autofluorescence in the nasal sector immediately after the photocoagulation session at 2 weeks, 4 weeks and 12 weeks. 6 measurements of the spacing between two spot burns were systematically recorded for each patient using Photoshop software.

Results: : Parameters used were as follows: power of 350 to 750 mW, duration: 20 ms, size: 200 micrometers, pattern: 4x4, distance between spots: 1 spot. There was no tendency for enlargement of photocoagulation scars between photography and FAF taken immediately after coagulation and those taken during the follow-up examinations.

Conclusions: : It is customary to see a gradual expansion in size of scars with the conventional laser. A decrease in the diffusion of the thermal effect may reduce this phenomenon with a short duration PASCAL laser. We did not observe a progressive enlargement of the scars obtained with the PASCAL in the examination period of 3 months. This data and its clinical implication in the long term, to be reviewed by other studies to assess the possible need to densify panretinal photocoagulation with the PASCAL laser.

Keywords: laser • retina • diabetic retinopathy