Use of optical coherence tomography (OCT) and indirect ophthalmoscopy in the diagnosis of macular edema in diabetic patients

Objectives: To evaluate the use of Optical Coherence Tomography (OCT) in the diagnosis of macular edema (ME) in diabetic patients in comparison to indirect ophthalmoscopy (IO) and, in addition, to study the characteristics of these patients. Methods: 165 patients were randomly selected to join the study in 1998. Ophthalmological, clinical and laboratory examinations were performed for all these patients. Results: Diabetic retinopathy was identified in 143 eyes (44.7%) and ME in 58 (18.3% of the total and 40.5% of the patients with retinopathy). 82.7% (48) of the eyes with ME could be diagnosed with OCT, against 62.0% (36) with IO. Haemoglobin A1c was the only variable that showed a significant association with ME, when compared to control (p < 0.05). Retinopathy was associated with the presence of nephropathy (p = 0.01) and neuropathy (p = 0.001), but ME was not (NS for both). 68% of patients without ME had a visual acuity of more than 50%. Conclusions: OCT is a new method that can help the evaluation of ME in diabetic patients. It can be used not only to diagnose the lesion, but also to follow up the patients during treatment. High levels of haemoglobin A1c might be associated with the presence of ME. Diabetic complications (nephropathy and neuropathy) are associated with retinopathy but not with macular edema.