A spectral domain optical coherence tomography (SD-OCT) study of intraretinal hyperreflective foci and its relationship with visual acuity and grades of retinopathy among patients of diabetes mellitus in Indian population.

Background: Hyperreflective foci (HRF) are biomarkers in detection of diabetic retinopathy (DR). Presence of HRF on spectral domain optical coherence tomography (SD-OCT) can give a correlation with visual acuity change and grades of DR. Purpose of this study is to determine the presence, location, and role of HRF in the retina of DM patients with and without retinopathy.

Methods: A total of 192 eyes of patients suffering from type II DM were evaluated. Patients were divided into 2 groups, with Group A having diabetes without retinopathy (20 patients) and group B (76 patients) having diabetes and various grades of retinopathy. SD-OCT was performed in all patients, passing through the center of fovea. On OCT, presence and absence of HRF were noted. Characteristics of the hyper-reflective spots were evaluated: location, shape, size, back shadowing and association with central macular thickness (CMT), visual acuity, and grades of retinopathy.

Results: HRF were present in 169 eyes (88%) out of 192 eyes. The shape and location of HRF tend to change with disease progression. HRF were significantly associated with increasing grades of retinopathy (χ2 = 57.586, p < 0.01) Association of macular edema was significant with both retinopathy (χ2 = 8.895, p < 0.05) and HRF (χ2 = 34.720, p < 0.01). Association of best-corrected visual acuity with HRF (χ2 = 21.232, p < 0.01), macular edema (χ2 = 86.960, p < 0.01), and CMT (χ2 = 47.959, p< 0 .01) was significant.

Conclusion: HRF is a great indicator for early diagnosis of subclinical retinopathy and can be used to monitor the progression of disease and development of macular edema. Significant difference is present in HRF distribution and morphology.