Abstract
Purpose::
Panretinal photocoagulation (PRP) requires the ablation of peripheral retinal tissue. To our knowledge, there has been no literature studying the effects of PRP on the optic nerve. This study examines the possible effect of PRP on the optic disc.
Methods::
In a retrospective study, medical records of patients who underwent PRP for proliferative diabetic retinopathy at the Yale Eye Center were reviewed. Only patients who had Kodachrome photographs of the optic disc before and after PRP were included. Patients who had previously received PRP or underwent vitrectomy prior to photographs were excluded. Photographs of the optic disc were then masked and presented to a masked ophthalmologist for analysis. The cup-to-disc ratio and color of the optic disc were recorded. Five grades of optic disc pallor were defined and standard photographs were selected representing each grade, where 5 indicated the healthiest-appearing color.
Results::
50 eyes met the inclusion criteria. Prior to PRP, these eyes had a mean cup-to-disc ratio of 0.28 (95% CI 0.25-0.32) and a mean color grade of 3.96 (95% CI 3.75-4.17). Mean cup-to-disc ratio was 0.31 (95% CI 0.28-0.35) and mean color grade was 3.36 (95% CI 3.12-3.60) after these eyes received PRP treatment. Using a paired t-test, a significant increase in cup-to-disc ratio (p=0.046) and a significant increase in optic disc pallor (p<0.00005) were found.
Conclusions::
Our results suggest a possible mild increase in cup-to-disc ratio and optic disc pallor in eyes receiving PRP. Further studies are necessary to fully evaluate the effect of PRP on the optic nerve.
Keywords: diabetic retinopathy • optic disc • laser