Can optical coherence tomography predict early retinal microvascular pathology in type 1 diabetic adolescents without minimal diabetic retinopathy? A single-centre study

BACKGROUND: Optical coherence tomography (OCT) has been proven useful in measuring retinal thickness and volumes in patients with diabetes. OBJECTIVE: To test whether OCT is able to identify early retinal changes and its potential correlations with metabolic parameters and other microvascular complications. PATIENTS AND METHODS: Thirty patients with type 1 diabetes without minimal diabetic retinopathy (MDR) (17 males, 13 females, aged 14.3±2.4 years) compared with age-matched healthy volunteers were examined with OCT. Diabetes duration, anthropometric measurements, HbA1c, other microvascular complications (nephropathy, autonomic and peripheral neuropathy) and total serum cholesterol were determined. RESULTS: No statistically significant differences were found between patients with (n=15) and without microvascular complications (n=15) compared to controls regarding retinal volume, nerve fibre layer volume (temporal and nasal quadrants) and ganglion cell layer area in both eyes. No correlation was found between the ganglion cell layer area and the clinical and laboratory characteristics of the patients, except a negative correlation with total serum cholesterol (r=-0.369, p=0.049). The best cut-off value of ganglion cell layer area to detect the level at which thinning of this layer occurs was >1900 pixels. CONCLUSION: Our study suggests that there is no advantage in performing OCT routinely in patients with type 1 diabetes mellitus without MDR. OCT did not show changes in retinal thickness in those patients compared to control. So OCT did not seem to be useful in the preclinical stages of diabetic retinopathy. Therefore, the conventional diagnostic methods are mandatory to detect early diabetic retinopathy.