Background: The diabetic retina undergoes significant degenerative changes, particularly in the retinal nerve fibre layer (RNFL), alongside notable vascular alterations. These changes include the loss of RNFL and modifications within the inner retina. Researchers have extensively studied the association between these retinal alterations and metabolic control in diabetic patients, yielding varied results.
Aim: To evaluate the thickness of the peripapillary retinal nerve fibre layer (RNFL) in individuals with Type II diabetes mellitus, both with and without diabetic retinopathy, and to compare these findings with those of healthy individuals.
Materials and Methods: 120 patients were enrolled in the study, divided into three groups: 40 healthy controls, 40 patients with diabetes without retinopathy, and 40 patients with diabetic retinopathy. Optical coherence tomography (OCT) scans were performed on both eyes of all participants to assess the RNFL and ganglion cell complex (GCC). The parameters obtained were then analysed in relation to the patient's metabolic control.
Results: Significant RNFL thinning was observed in the superior temporal (ST) (p = 0.036), superior nasal (SN) (p = 0.028), nasal upper (NU) (p = 0.04), and nasal lower (NL) (p = 0.029) quadrants around the optic disc in the diabetic retinopathy group. Additionally, HbA1c levels demonstrated a weak negative correlation with RNFL thickness.
Conclusion: This study shows that neurodegeneration is an early component of diabetic retinopathy.
Keywords: Diabetes mellitus, Retinal nerve fibre layer thickness, Optical coherence tomography, Ganglion cell complex, HBA1c.
