A study of corneal thickness, shape and collagen organisation in keratoconus using videokeratography and X-ray scattering techniques.
In keratoconus, the cornea becomes progressively ectactic resulting in severe visual impairment. Here, we use a combination of videokeratography and synchrotron X-ray diffraction to investigate the relationship between corneal shape and thickness, and the distribution and predominant orientation of stromal fibrillar collagen in five keratoconus corneas. In all but the least advanced case, the thinning and ectasia measured in vivo using corneal videokeratography was accompanied by corresponding changes in the relative distribution and orientation of stromal collagen in the excised corneal buttons. Although the most severe case of keratoconus possessed the most pronounced stromal collagen alterations, and only a minor disruption to stromal collagen arrangement was seen in the least advanced case, a variability in the extent of stromal collagen alteration was seen between these clinical extremes. The observed abnormalities in collagen distribution and orientation are consistent with a mechanism of keratoconus progression that involves inter-fibrillar or inter-lamellar slippage causing a redistribution of tissue within the cornea.
Hayes
Sally
S
Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff, CF10 3NB, United Kingdom. denniss@cf.ac.uk
Boote
Craig
C
Tuft
Stephen J
SJ
Quantock
Andrew J
AJ
Meek
Keith M
KM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003094:Collagen / Q000032:analysis; D003315:Cornea / Q000473:pathology* / Q000648:ultrastructure; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000473:pathology*; D008297:Male; D012542:Scattering, Radiation; D014965:X-Rays
D003094:Collagen