Peripapillary RNFL thickness changes after panretinal photocoagulation

Purpose To evaluate changes in peripapillary retinal nerve fiber layer (RNFL) thickness as determined by spectral domain optical coherence tomography (SD-OCT) after panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR). Methods Forty-two eyes of 42 diabetic patients who were scheduled for PRP were enrolled in this interventional case series. Peripapillary RNFL thickness was measured using SD-OCT (OCT 1000; Topcon Co., Tokyo, Japan) at baseline and 1, 3, and 6 months after PRP. Results Mean global RNFL thickness was increased significantly by 3 μm (p = 0.04) 1 month after PRP and was then decreased marginally significantly by 2.4 μm at 6 months (p = 0.054) as compared to baseline values. After 1 month, RNFL thickness was increased in all quadrants, but only changes in the temporal quadrant were significant (p = 0.009). At 6 months, progressive RNFL thinning occurred in all quadrants; however, only changes in the superior quadrant were significant (p = 0.041). Visual acuity was improved by an average of 0.02 logMAR after 6 months, but this change was not statistically significant. Conclusions Shortly after PRP, RNFL thickness (as determined by SD-OCT) increases, but a decrease in RNFL thickness occurs at 6 months post-PRP. RNFL thickness changes based on OCT should be interpreted with caution in diabetic eyes undergoing PRP.