Corneal confocal microscopy: a non-invasive surrogate of nerve fibre damage and repair in diabetic patients.
OBJECTIVE
The accurate detection, characterization and quantification of human diabetic neuropathy are important to define at risk patients, anticipate deterioration, and assess new therapies. Corneal confocal microscopy is a reiterative, rapid, non-invasive in vivo clinical examination technique capable of imaging corneal nerve fibres. The aim of this study was to define the ability of this technique to quantify the extent of degeneration and regeneration of corneal nerve fibres in diabetic patients with increasing neuropathic severity.


METHODS
We scanned the cornea and collected images of Bowman's layer (containing a rich nerve plexus) from 18 diabetic patients and 18 age-matched control subjects.


RESULTS
Corneal nerve fibre density (F(3)=9.6, p<0.0001), length (F(3)=23.8, p<0.0001), and branch density (F(3)=13.9, p<0.0001) were reduced in diabetic patients compared with control subjects, with a tendency for greater reduction in these measures with increasing severity of neuropathy.


CONCLUSIONS
Corneal confocal microscopy is a rapid, non-invasive in vivo clinical examination technique which accurately defines the extent of corneal nerve damage and repair and acts as a surrogate measure of somatic neuropathy in diabetic patients. It could represent an advance to define the severity of neuropathy and expedite assessment of therapeutic efficacy in clinical trials of human diabetic neuropathy.
Department of Medicine, Manchester Royal Infirmary, Oxford Road, Manchester, UK. Rayaz.A.Malik@man.ac.uk
R A
RA
Malik
P
P
Kallinikos
C A
CA
Abbott
C H M
CH
van Schie
P
P
Morgan
N
N
Efron
A J M
AJ
Boulton
D003315:Cornea / Q000294:innervation* / Q000473:pathology*; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology; D003924:Diabetes Mellitus, Type 2 / Q000473:pathology; D003925:Diabetic Angiopathies / Q000473:pathology*; D003929:Diabetic Neuropathies / Q000473:pathology*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009416:Nerve Regeneration / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results
D006442:Glycated Hemoglobin