The early diagnostic value of corneal laser confocal microscopy for small neuropathy in elderly patients with type 2 diabetes mellitus

Abstract

Objective To investigate the early diagnostic value of cornel confocal microscopy for the screening of small neuropathy in elderly patients with type 2 diabetic mellitus. Methods In the prospective study, 96 elderly patients with diabetes as study group and 46 patients with non-diabetes as the control group were continuously collected from our hospital endocrinology and ophthalmology out patients during May 2014 to February 2016.The 96 cases of type 2 diabetes were subdivided into 47 patients with diabetic peripheral neuropathy(DPN)and 47 patients with non-diabetic peripheral neuropathy(non-DPN). Results The diabetes course was shorter in non-DPN group than in DPN group(P=0.000). The levels of glycosylated hemoglobin and urine albumin were lower in the non-DPN than in the DPN(P=0.072, 0.007, respectively). The corneal nerve fiber density was lower in the DPN group than in NDPN group(P=0.000). Corneal nerve fiber density was higher in control group than in DPN and NDPN group.The differences in number of corneal nerve fibers showed no statistical significance between DPN and NDPN group(χ2=2.391, P=0.314). But the number of corneal nerve fibers was significant less in DPN and NDPN group than in control group(χ2=16.014, P=0.000). The negative correlation was found between the course of disease and corneal fibrous density by using single factor linear regression analysis.The number of corneal nerve fibers was lower in smoking group than in non-smoking group(P=0.003). The multiple linear regression analysis showed that duration of diabetes was a risk factor for diabetic neuropathy. Conclusions In some elderly diabetic patients with non-neuropathy, corneal nerve fiber density and number have been significantly decreased before nerve conductive velocity is reduced.Therefore, corneal confocal microscopy can be used to detect and diagnose small diabetic neuropathy in elderly patients with diabetes mellitus. Key words: Corneal; Microscopy, confocal; Diabetic neuropathies