Corneal nerve loss in children with Type 1 diabetes mellitus without retinopathy or microalbuminuria.

INTRODUCTION/AIM Corneal confocal microscopy is a rapid, non-invasive ophthalmic technique to identify sub-clinical neuropathy. The aim of this study was to quantify corneal nerve morphology in children with type 1 diabetes mellitus compared to age-matched healthy controls using corneal confocal microscopy. METHOD Twenty participants with type 1 diabetes mellitus (age 14±2 years, diabetes duration 4.08±2.91 years, glycated hemoglobin 9.3±2.1%) without retinopathy or microalbuminuria and 20 healthy controls were recruited from outpatient clinics. Corneal confocal microscopy was undertaken and corneal nerve fiber density (no./mm2 ), corneal nerve branch density (no./mm2 ), corneal nerve fiber length (mm/mm2 ), corneal nerve fiber tortuosity and inferior whorl length (mm/mm2 ) were quantified manually. RESULTS Corneal nerve fiber density (22.73±8.84 vs. 32.92±8.59; P<0.001), corneal nerve branch density (26.19±14.64 vs. 47.34±20.01; P<0.001), corneal nerve fiber length (13.26±4.06 vs. 19.52±4.54; P<0.001) and inferior whorl length (15.50±5.48 vs. 23.42±3.94; P<0.0001) were significantly lower, whilst corneal nerve fiber tortuosity (14.88±5.28 vs. 13.52±3.01; P=0.323) did not differ between children with type 1 diabetes mellitus and controls. Glycated hemoglobin correlated with corneal nerve fiber tortuosity (P<0.006) and aspartate aminotransferase correlated with corneal nerve fiber density (P=0.039), corneal nerve branch density (P=0.003), and corneal nerve fiber length (P=0.037). CONCLUSION Corneal confocal microscopy identifies significant sub-clinical corneal nerve loss, especially in the inferior whorl of children with type 1 diabetes mellitus without retinopathy or microalbuminuria.