To evaluate peripapillary nerve fiber layer changes after pan-retinal photocoagulation for diabetic retinopathy.

In this clinical trial, 45 eyes from 45 diabetic patients were enrolled. Complete ophthalmic examinations including BCVA, IOP, anterior segment examination with slit lamp and dilated fundus examination were performed. All the participants underwent Peripapillary SD-OCT at baseline. Peripapillary RNFL thicknesses were measured at, 1 month, 3 months and 6 months post laser treatment. RNFL changes and vision changes were analyzed.

visual acuity was increased by an average of 0.02 log MAR after 6 months. However this difference was not statistically significant. The mean 360º nerve fiber layer thickness increased significantly by 3µm (P=0.031) at 1 month then decreased significantly at 6 months compared with baseline (P=0.022). After 1 month mean RNFL thickness in all of the quadrants were increased but there were significant changes only in the temporal quadrant (P=0.005). After 6 months there was progressive thinning of RNFL in all of the quadrants but only in superior quadrant was statistically significant compared with baseline (P= 0.016).

PRP increases RNFL thickness at short term, and decreases RNFL thickness in long term and in diabetic eyes OCT changes should be interpreted with caution.