Long-term longitudinal retinal changes after conventional and pattern scan laser panretinal photocoagulation in diabetic retinopathy.

PURPOSE: Comparison the effect of conventional and pattern scan laser (PASCAL) panretinal photocoagulation (PRP) on macula and optic disc in diabetic retinopathy (DR).

METHODS: This retrospective study included 57 patients. In the conventional laser group, PRP was completed using the LightMed LightLas 532 laser device in accordance with the ETDRS protocol. In the pattern laser group, it was completed in a single session using PASCAL device with 20 ms pulse duration and multispot pattern. Central macular thickness (CMT) and retinal nerve fiber layer (RNFL) thickness were evaluated before laser treatment and at 1, 6 and 12 months after treatment.

RESULTS: There were 30 eyes in the conventional laser group and 27 eyes in the PASCAL group. There was no significant difference between the groups in terms of age (p=0.560), sex (p=0.866), duration (p=0.498) and stage (p=0.503) of diabetes, visual acuity (p=0.104) and intraocular pressure (p=0.963).In both groups, CMT increased significantly (p ˂0.001), while RNFL thickness decreased significantly (p ˂0.001) at 12 months. While CMT and mean RNFL thickness increased in the first month in both groups, it decreased progressively until the 12th month.

CONCLUSION: Conventional and pattern laser systems used in the treatment of DR cause an increase in CMT and thinning of RNFL thickness in the long term. This change is more in the conventional laser group compared to the pattern laser.