To assess for evidence of small nerve fiber pathology in obese children and adolescents using corneal confocal microscopy (CCM).

The global prevalence of obesity among children and adolescents has increased dramatically over the past few decades, and childhood obesity has become a significant public health concern. Studies have shown an increased prevalence of neuropathic symptoms in obese children indicating small nerve fiber pathology. We have previously used corneal confocal microscopy (CCM), a rapid, non-invasive ophthalmic technique, to show corneal nerve fiber loss in adults with painful diabetic neuropathy, adults with obesity and children with type 1 diabetes. 

Twenty obese children and adolescents (age 14.0 ± 2.51 years, BMI 37.27 ± 7.14 kg/m²) and 20 healthy controls (age 12.83 ± 1.91 years, BMI 22.27 ± 5.47 kg/m²) underwent vibration perception threshold (VPT) assessment and CCM to quantify corneal nerve fiber density (CNFD) (no./mm²), corneal nerve branch density (CNBD) (no./mm²) and corneal nerve fiber length (CNFL) (mm/mm²). Obese children also underwent body composition analysis using TANITA to assess body fat percentage. 

Obese children had a normal VPT (3.20 ± 0.95 vs. controls). There was a non-significant trend for a lower CNFD (19.01 ± 5.2 vs. 21.91 ± 4.6; P=0.06), but no difference in CNBD (33.02 (26.13-42.04) vs. 35.04 (29.46-5134); P=0.25) or CNFL (14.5 ± 2.6 vs. 14.4 ± 2.1; P=0.89) in obese children compared to healthy controls. There was no correlation between CNFD (P=0.643), CNBD (P=0.950) and CNFL (P=0.598) with body fat percentage.

There is no evidence of abnormal vibration perception or small nerve fiber damage in obese children and adolescents.