Changes in the Macular Ganglion Cell Complex Thickness and Central Macular Thickness after Argon Laser Panretinal Photocoagulation

Purpose: To evaluate the changes in the macular ganglion cell complex (GCC) thickness and central macular thickness (CMT) as measured by spectral domain optical coherence tomography (OCT) post-argon laser panretinal photocoagulation (PRP). Methods: The medical records of 25 patients with proliferative diabetic retinopathy (PDR) who underwent PRP, 29 patients with non-proliferative diabetic retinopathy (NPDR), and 29 patients with diabetes but without diabetic retinopathy (DR) were analyzed. The patients who received PRP were followed up for one year. The follow-up measurements were evaluated at baseline, and months 1, 6, and 12 post-argon laser PRP. The baseline values of CMT and GCC thickness were compared among the groups to assess changes with PRP therapy. Results: The CMT gradually increased in months 1 and 6 and then decreased; however, it was significantly higher than the baseline value at month 12 in the PDR group post-PRP. The GCC thickness also increased at months 1 and 6 in almost all segments of the macula, but at month 12 decreased to the baseline value. There was no correlation between the increasing thickness of the macula and change in the GCC thickness post-PRP period in the PDR group. In addition, no significant correlation was detected between the GCC thickness and best-corrected visual acuity during all follow-up visits. Conclusions: GCC thickness increased significantly until month 6 compared with baseline values in most of the macular segments post-PRP in the PDR group. The GCC thickness at month 12 was not different from the baseline thickness in any of the macular segments.