Psychophysical exams as early indicators of diabetic retinopathy

Retinopathy is a serious and common complication of diabetes that represents the leading cause of blindness, among people of working age, in developed countries. It is estimated that the number of people with diabetic retinopathy (DR) will increase from 126.6 million in 2011 to 191 million by 2030. The visual function that seems to be affected first in the course of DR is probably the contrast sensitivity; in addition, being mainly a macular function, the perception of colour is also compromised. Moreover, the duration of the disease, the levels of glycated haemoglobin (HbA1c) and the presence of cystoid macular oedema are strongly associated with the impairment of fixation stability in patients with diabetes with clinically significant macular oedema, suggesting the possible diagnostic role of microperimetry. The test of contrast sensitivity and the microperimetry and the chromatic sensitivity tests have proved to be useful, safe, reproducible and inexpensive tools to diagnose the disease early.