Lens autofluorescence ratio as a noninvasive marker of peripheral diabetic neuropathy.

INTRODUCTION Diabetes and its complications are the significant cause of morbidity and mortality. Advanced glycation end products play a major role in the pathogenesis of diabetes complications. OBJECTIVES The aim of the study was to investigate the possible use of a biomicroscope (ClearPath DS­­120), which shows the age­­adjusted lens fluorescence ratio (LFR), for the diagnosis of diabetic peripheral neuropathy (DPN). PATIENTS AND METHODS A total of 160 patients with type 2 diabetes who underwent an LFR measurement were recruited to this study. DPN was defined as the presence of neuropathic pain or feet sensory loss (or both). Neurothesiometer, monofilament test, and DN4 test results were used for the diagnosis of DPN. RESULTS The LFR of 43 patients (27%) was higher than the expected levels. According to the DN4 questionnaire, 35 of 160 patients (21%) had neuropathic pain. Thirty­­seven patients (23%) had higher vibration perception thresholds than expected (>25 V). The monofilament test showed that 42 patients (26%) seemed to be affected by DPN. All of the tests, when considered individually, revealed that patients with higher LFR had more problems related to DPN (P <0.05). High LFR had a sensitivity of 50% and a specificity of 81% in the diagnosis of DPN. Although there was no significant difference in fasting blood glucose levels, we observed that HbA1c levels were higher and diabetes duration was longer in patients with higher LFR (P <0.05). CONCLUSIONS The measurement of LFR may have clinical utility for a noninvasive detection of DPN.