Date of Award


Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Ron A. Adelman, MD


This study aims to examine the possible effect that pan-retinal photocoagulation (PRP) performed as treatment for proliferative diabetic retinopathy (PDR) has on the optic disc. In a retrospective study, photographs of the optic disc before and after PRP, as well as photographs of untreated eyes for the control group, were evaluated for cup-to-disc ratio and optic disc pallor as gross measures of optic nerve health. A 5-grade scheme for optic color was devised for this study by selecting representative photographs for each grade, where 5 indicated the healthiest-appearing color. Kappa statistics indicated strong intra- and inter-observer consistency of observations for both cup-to-disc ratio and optic color (0.61 and 0.79, respectively). A paired t-test showed that change in optic pallor was significant after treatment with PRP (p = 0.0004). However, when comparing to the change in the control group using a Students t-test, no significance was found (p = 0.387). No significant change was found in cup-to-disc ratio. A few conclusions can be made from this study. First, the newly created grading scheme for optic pallor is both reliable and reproducible. While PRP treatment may cause an increase in optic pallor, the change is not significantly different than that seen with merely the passage of time. Lastly, cup-to-disc ratio was not significantly affected by PRP treatment. Further studies may be indicated to elaborate on the effect of PRP on the optic nerve.