Focal loss in ganglion cell complex in diabetic peripheral neuropathy

Abstract

Purpose: To investigate the relationship between diabetic peripheral neuropathy and abnormalities in ganglion cell complex (GCC) (focal loss volume (GCC FLV) and global loss volume (GCC GLV)

Methods: One hundred and ninety three individuals (84 with type 1 diabetes, 67 with type 2 diabetes and 42 healthy controls) underwent GCC evaluation using optical coherence tomography. The probability of FLV and GLV being abnormal (borderline or outside normal loss in comparison to population norms) was determined for all participants. Forty four individuals had diabetic neuropathy based on a modified neuropathy disability score (NDS) (expressed as mean ± standard error of the mean). A binary logistic regression analysis was performed in individuals with diabetes, to investigate the relationship of diabetic neuropathy with (i) abnormal FLV and (ii) abnormal GLV, in separate regression models, taking into account, the presence of diabetic retinopathy (DR), type of diabetes, age, sex, duration of diabetes and HbA_1c levels

Results: Twenty five per cent of individuals with diabetic neuropathy had significantly abnormal FLV compared to 11% of those without neuropathy and 5% in the control group (p = 0.011). Fourteen per cent of individuals with diabetic neuropathy, 10% of those without neuropathy and 2% in the control group had abnormal GLV; these differences were not statistically significant (p = 0.185). For every unit increase in NDS, the odds of having an abnormal FLV increased by a multiplicative factor of 1.25 (p = 0.007), when controlled for DR, type of diabetes, age, sex, duration of diabetes and HbA_1c levels. For every year increase in age, the odds of having an abnormal GLV increased by a multiplicative factor of 1.07 (p = 0.026), when controlled for NDS, DR, type of diabetes, sex, duration of diabetes and HbA_1c levels

Conclusions: Diabetic peripheral neuropathy is associated with macular focal ganglion cell volume loss, independent of diabetic retinopathy, type of diabetes, age, sex, duration of diabetes and HbA_1c levels. The study demonstrated a significant relationship between focal neuronal damage in the retina and in the peripheral nervous system in diabetes. As the macular region subserves the central visual field, a compromise to this region can pose a threat to the visual integrity and therefore necessitates further investigation