Pupilometria dinâmica: aplicação na detecção e avaliação da neuropatia autonômica diabética e estudo da correlação entre a resposta temporal da pupila ao estímulo visual e a glicemia

Abstract

Autonomic neuropathy (AN) is a common and serious complication of diabetes. Early detection is essential to enable appropriate interventional therapy. Dynamic pupillometry has been proposed as simples and more sensitive tool to detect subclinical autonomic dysfunction. Moreover, the effect of actual glycaemia on autonomic function in diabetic subjects is unknown. The aims of this study weere: 1) to investigate pupil responsiveness in diabetic subjects with and without cardiovascular autonomic neuropathy (CAN), and in diabetic subjects with and without diabetic peripheral neuropathy (DPN) using dynamic pupillometry and, 2) to study the correlation between the pupil responsiveness in diabetic subjects and the actual glycaemia. In the first study, two tests were applied. during the first test, one flash was administered and the pupil response recorded for 3 seconds. In the second test, twenty-five flashes at one-second intervals were administered and the pupil response recorded for 30 seconds. Several time related parameters were computed from the results. A total of 36 diabetic subjects and 22 healthy volunteers took part in the study. Our results show that diabetic subjects with and without CAN, and with or without DPN have sympathetic and parasympathetic dysfunction evidenced by diminished amplitude reflexes and significant smaller pupil diameter. It suggests that pupillary autonomic dysfunction occurs early, before a more generalized involvement of the autonomic nervous system. In the second study, only the first test was applied in 4 diabetic subjects at three levels of glycaemia. Our results show that the pupil responsiveness is not affect of actual glycaemia. Dynamic pupillometry may provide a simple, inexpensive and non-invasive tool to screen high-risk diabetic patients for diabetic autonomic neuropathy.