title: In vivo corneal confocal microscopic analysis in patients with keratoconus.
abstract: OBJECTIVE
  To quantify corneal ultrastructure using laser scanning in vivo confocal microscopy (IVCM) in patients with keratoconus and control subjects.
  
  
  METHODS
  Unscarred corneas of 78 keratoconic subjects without a history of contact lens use and 36 age-matched control subjects were evaluated with slit-lamp examination (SLE), corneal topography and laser scanning IVCM. One eye was randomly chosen for analysis. Anterior and posterior stromal keratocyte, endothelial cell and basal epithelial cell densities and sub-basal nerve structure were evaluated.
  
  
  RESULTS
  IVCM qualitatively demonstrated enlarged basal epithelial cells, structural changes in sub-basal and stromal nerve fibers, abnormal stromal keratocytes and keratocyte nuclei, and pleomorphism and enlargement of endothelial cells. Compared with control subjects, significant reductions in basal epithelial cell density (5817±306 cells/mm(2) vs 4802±508 cells/mm(2), P<0.001), anterior stromal keratocyte density (800±111 cells/mm(2) vs 555±115 cells/mm(2), P<0.001), posterior stromal keratocyte density (333±34 cells/mm(2) vs 270±47 cells/mm(2), P<0.001), endothelial cell density (2875±223 cells/mm(2) vs 2686±265 cells/mm(2), P<0.001), sub-basal nerve fiber density (31.2±8.4 nerves/mm(2) vs 18.1±9.2 nerves/mm(2), P<0.001), sub-basal nerve fiber length (21.4±3.4 mm/mm(2) vs 16.1±5.1 mm/mm(2), P<0.001), and sub-basal nerve branch density (median 50.0 (first quartile 31.2 - third quartile 68.7) nerve branches/mm(2) vs median 25.0 (first quartile 6.2 - third quartile 45.3) nerve branches/mm(2), P<0.001) were observed in patients with keratoconus.
  
  
  CONCLUSIONS
  Significant microstructural abnormalities were identified in all corneal layers in the eyes of subjects with keratoconus using IVCM. This non-invasive in vivo technique provides an important means to define and follow progress of microstructural changes in patients with keratoconus.
authors.affiliation: Department of Ophthalmology, Necmettin Erbakan University Meram Faculty of Medicine, Konya 42080, Turkey.
authors.forename: Gulfidan
authors.initials: G
authors.lastname: Bitirgen
authors.affiliation: Department of Ophthalmology, Necmettin Erbakan University Meram Faculty of Medicine, Konya 42080, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Ozkagnici
authors.affiliation: Department of Ophthalmology, Selcuk University Faculty of Medicine, Konya 42075, Turkey.
authors.forename: Banu
authors.initials: B
authors.lastname: Bozkurt
authors.affiliation: Centre for Endocrinology and Diabetes, University of Manchester, Manchester M13 9NT, UK.
authors.forename: Rayaz A
authors.initials: RA
authors.lastname: Malik
keywords: corneal nerves; in vivo confocal microscopy; keratoconus