Association of Glucose Levels with Peripapillary Retinal Nerve Fiber Layer Thickness in Non-Proliferative Diabetic Retinopathy

Abstract

Asaad A. Ghanem, Ahmed A Ghanem, Mona S. Mady and Ahmed M Ghanem

Purpose: To assess whether degree of glycosylated hemoglobin levels influence peripapillary retinal nerve fiber layer thickness in patients with non-proliferative diabetic retinopathy.

Methods: A prospective observational cross section study was performed on 110 eyes included 30 eyes of 15 healthy control subjects and 80 eyes of 40 patients with non-proliferative diabetic retinopathy. Diabetic group was divided into two study groups, subgroup 1 with HbA1c that is less than 7% and subgroup 2 with HbA1c that is equal or more than 7%. Full ophthalmic examinations included best-corrected visual acuity, anterior segment evaluation, and intraocular pressure assessment. Peripapillary retinal nerve fiber layer thickness (RNFLT) was measured using a spectral-domain OCT (Topcon Corporation, Tokyo, Japan). Multivariable logistic regression models were used after controlling for the same sets of confounders. A value of P < 0.05 was considered significant.

Results: There was non-statistically significant difference regarding systemic hypertension, BCVA, intraocular pressure, while, there was statistically significant difference regarding smoking, body mass index, HBA1C, lipid profile between diabetic and control groups. There was statistically significant decrease in peripapillary RNFLT in superior quadrants in diabetics group with impairment of HBA1C (P<0.001). Peripapillary RNFLT was negatively correlated with HbA1c in the supe¬rior, inferior, and nasal quadrants, while it was positively correlated in the temporal quadrant

Conclusion: Impairment of glycemic control affects the peripapillary RNFLT mainly in the superior quadrant. The measurement of peripapillary RNFLT may become a useful method to monitor early retinal changes in diabetic patients.

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