DR not main cause of blindness in diabetics

Diabetic retinopathy (DR) is not the leading cause of ocular co-morbidity in diabetic subjects, according to a study published in the June 2008 issue of the British Journal of Ophthalmology.

Peter H. Scanlon, MBBS, MD, FRCP, DCH, DRCOG, DO, MRCOphth of Cheltenham General Hospital and colleagues conducted slip-lamp biomicroscopy examinations on diabetic subjects (n=1549) following assessment of best corrected visual acuity (BCVA) by a standardized logarithm of minimum angle resolution (logMAR).

The researchers found subnormal vision (logMAR ≥0.3) in 9.0% of subjects; blindness (logMAR ≥1.3), in 0.45%. For any given eye, sensitivity of subnormal vision was 33.4%, specificity was 85.9%, positive status was 18.6% and negative status was 93.0% predictive of DR. Lenticular opacity, macular degeneration, diabetic maculopathy, other media causes including corneal opacity, and amblyopia were found to be contributory causes of moderate visual loss (logMAR 0.50–0.98) or acuity blindness (logMAR ≥1.0) in 49%, 29%, 15%, 13% and 10% of subjects, respectively.

The researchers concluded that BCVA in isolation is not a reliable indicator of DR, and that DR is not the primary cause of vision loss in diabetic subjects.