Increased serum urea and creatinine levels correlate with decreased retinal nerve fibre layer thickness in diabetic retinopathy.

Correlation of increased levels of serum urea and creatinine with retinal nerve fibre layer (RNFL) thinning on spectral domain optical coherence tomography (SD-OCT) was studied in diabetic retinopathy (DR). Sixty consecutive cases and 20 healthy controls were included. Cases were divided into three groups: without DR, non-proliferative DR with macular oedema and proliferative DR with oedema. Serum urea and creatinine were measured using a standard protocol. Average (RNFL) was measured using SD-OCT. Increased severity of DR was associated with decrease in levels of serum urea and serum creatinine levels. RNFL thinning correlated positively with increase in serum urea and creatinine levels.