Case-control study reveals retinal nerve fiber and ganglion cell thinning in type 2 diabetes, indicating early neurodegeneration linked to glycemic control.
Key Points
To compare retinal nerve fiber layer and ganglion cell-inner plexiform layer thicknesses between type 2 diabetic patients with and without diabetic retinopathy and healthy controls.
Comparative case-control study examining 58 eyes of type 2 diabetic patients (33 without diabetic retinopathy, 25 with moderate retinopathy) and 58 age-, sex-, and IOP-matched healthy control eyes.
Assessed peripapillary RNFL and macular GCIPL thickness using spectral-domain optical coherence tomography (SD-OCT).
Evaluated systemic risk factors, including HbA1c, presence of diabetic retinopathy, and vascular comorbidities, using multivariate linear regression.
Average, superior, and inferior RNFL thicknesses were significantly lower in diabetic eyes compared to controls (p<0.001, p=0.005, and p=0.01, respectively).
Macular GCIPL thickness was significantly reduced overall in diabetic eyes (p<0.001), though no significant difference emerged between diabetic eyes without retinopathy and healthy controls across all quadrants.
Multivariate regression showed that diabetes duration and HbA1c levels correlated with RNFL and GCIPL loss in diabetic eyes, while hypertension and lipid disorders were risk factors in controls.