title: The morphologic characteristics of corneal nerves in advanced keratoconus as evaluated by acetylcholinesterase technique.
abstract: OBJECTIVE
  To study the morphologic characteristics of corneal nerves in patients with advanced keratoconus using the acetylcholinesterase technique in corneal whole mounts.
  
  
  METHODS
  Prospective, observational case series.
  
  
  METHODS
  Fourteen corneal buttons from 14 keratoconic patients (9 males and 5 females; mean age, 34.3 years) who had undergone keratoplasty for advanced keratoconus and 6 corneal buttons from 6 normal corneas were included. Whole mounts were stained for acetylcholinesterase and were scanned with a novel digital pathology scanning microscope.
  
  
  RESULTS
  Seventy-one percent of keratoconic corneas demonstrated central stromal nerve changes, which included thickening, tortuosity, nerve spouting, and overgrowth. The nerve changes ranged from early to extensive and could be separated into 3 different grades. The central stromal nerves were abnormally thicker (18.9 ± 14.7 μm) than in controls (8.11 ± 3.31 μm; P < .001). The thickness of peripheral stromal nerves (12.6 ± 3.1 μm) was similar to that of controls (14.86 ± 5.60 μm; P = .072). Subbasal nerves showed changes in the form of loss of radial orientation and increased tortuosity, especially at the cone apex. At the cone base, a concentric arrangement of subbasal nerves was found in 43% of cases. Localized thickenings of subbasal nerves also were observed at their origin from the bulbous terminations of sub-Bowman nerves. The terminal bulbs, too, were enlarged. The mean diameter of the subbasal nerves in keratoconus (4.11 ± 0.60 μm) did not differ from that of the controls (4.0 ± 0.61 μm; P = .422).
  
  
  CONCLUSIONS
  This study provides additional histologic evidence of the involvement of corneal nerves in keratoconus and suggests further that they may play a role in the pathophysiologic factors and progression of the disease.
authors.affiliation: Division of Ophthalmology and Visual Sciences, School of Clinical Sciences, University of Nottingham, Nottingham, United Kingdom; Department of Surgery, College of Medicine, The University of Basrah, Basrah, Republic of Iraq.
authors.forename: Mouhamed Ali
authors.initials: MA
authors.lastname: Al-Aqaba
authors.affiliation: Division of Ophthalmology and Visual Sciences, School of Clinical Sciences, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Lana
authors.initials: L
authors.lastname: Faraj
authors.affiliation: Division of Ophthalmology and Visual Sciences, School of Clinical Sciences, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Usama
authors.initials: U
authors.lastname: Fares
authors.affiliation: Division of Ophthalmology and Visual Sciences, School of Clinical Sciences, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Ahmad Muneer
authors.initials: AM
authors.lastname: Otri
authors.affiliation: Division of Ophthalmology and Visual Sciences, School of Clinical Sciences, University of Nottingham, Nottingham, United Kingdom. Electronic address: Harminder.dua@nottingham.ac.uk.
authors.forename: Harminder S
authors.initials: HS
authors.lastname: Dua
mesh_terms: D000109:Acetylcholine; D000110:Acetylcholinesterase / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000294:innervation*; D003319:Corneal Stroma / Q000294:innervation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007640:Keratoconus / Q000201:enzymology / Q000473:pathology* / Q000601:surgery; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D009882:Ophthalmic Nerve / Q000201:enzymology / Q000473:pathology*; D011446:Prospective Studies; D013194:Staining and Labeling / Q000379:methods; D020433:Trigeminal Nerve Diseases / Q000201:enzymology / Q000473:pathology*; D055815:Young Adult
chemical_list: D000110:Acetylcholinesterase; D000109:Acetylcholine