PURPOSE: To examine the effect of panretinal photocoagulation (PRP) on the retinal nerve fiber layer (RNFL) thickness in patients with diabetic retinopathy. METHODS: Subjects included 118 eyes for a treatment group and 164 eyes for a control group. The peripapillary RNFL thickness was measured before and 6 months after PRP in treatment group. In control group, the peripapillary RNFL thickness was measured at baseline and 6 months later. The relationships between changes in RNFL thickness and the number of laser burns, duration of diabetes, HbA1c level, and vision change were analyzed. RESULTS: After 6 months, the RNFL thickness decreased an average of 2.12 microm and 0.93 microm in the treatment and control groups. However, the changes between the two groups were not statistically significant. The relationship between the number of laser burns and changes in RNFL thickness was not significant. No differences were found between changes in the RNFL thickness and the duration of diabetes in either group. However, in the treatment group a higher HbA1c level was correlated with a greater decrease in post-PRP RNFL thickness. This relationship was not observed in the control group. The difference in the change of the RNFL thickness between the two groups was statistically significant. Vision increased an average of 0.02 and 0.01 after 6 months in the treatment and control groups, respectively. However, this difference was not statistically significant. CONCLUSIONS: Although a decrease in peripapillary RNFL thickness was observed in the treatment group after 6 months, it was not statistically significant compared to control group. However, the decrease was greater when the blood HbA1c level was higher.
Diabetic Retinopathy/*surgery ; Follow-Up Studies ; Humans ; Laser Coagulation/*methods ; Middle Aged ; Nerve Fibers/*pathology ; Optic Disk/*pathology/surgery ; Postoperative Period ; Retinal Ganglion Cells/*pathology ; Retrospective Studies ; Tomography, Optical Coherence ; Treatment Outcome ; Visual Acuity ; Visual Fields

PURPOSE: To assess the diagnostic efficacy of macular and peripapillary retinal thickness measurements for the staging of diabetic retinopathy (DR) and the prediction of disease progression. METHODS: In this prospective study, 149 diabetic patients (149 eyes) and 50 non-diabetic control subjects were included. Baseline optical coherence tomography was employed to measure retinal thickness in the macula (horizontal, vertical, and central) and the peripapillary zone (superior, inferior, nasal, and concentric to the optic disc). Seven baseline parameters were correlated with the DR stages identified by fluorescein angiography. Baseline retinal thickness was compared between groups of patients requiring panretinal photocoagulation (PRP) within 6 months (PRP group) and patients not requiring PRP (No-PRP group). RESULTS: Macular and peripapillary retinal thicknesses in diabetic subjects were significantly greater than that in normal controls (p<0.05). All retinal thickness parameters, and particularly peripapillary circular scans, tended to increase with increasing DR severity (p<0.05). The baseline thicknesses of the peripapillary circular scans were greater in the PRP group than in the no-PRP group (p<0.05). CONCLUSIONS: Peripapillary retinal thickness may prove to be a useful criterion for DR severity and may also serve as an indicator of disease progression.
Aged ; Diabetic Retinopathy/*diagnosis/surgery ; Disease Progression ; Female ; Fluorescein Angiography ; Humans ; Light Coagulation ; Male ; Middle Aged ; Optic Disk ; Prospective Studies ; Retina/*pathology/surgery ; *Severity of Illness Index ; *Tomography, Optical Coherence