title: Corneal densitometry as an indicator of corneal health.
abstract: OBJECTIVE
  To establish prospectively the normal values of corneal density of healthy subjects using the Pentacam Scheimpflug system (Oculus, Inc., Wetzlar, Germany) and to investigate alteration in corneal density during active and healed stages of bacterial keratitis.
  
  
  METHODS
  Prospective, comparative case series.
  
  
  METHODS
  Sixty-four eyes of 40 healthy controls and 36 eyes of 35 patients with bacterial keratitis were studied.
  
  
  METHODS
  This study was conducted at the Queen's Medical Centre, Nottingham, United Kingdom. A Pentacam system was used to study corneal density. Corneal densitometry readings in subjects with bacterial keratitis were recorded during the active stage and 4 to 6 weeks after complete healing. Densitometry was recorded at the site of infection and at a point in clear cornea furthest away from the infectious infiltrate. Corneal thickness also was measured.
  
  
  METHODS
  Densitometry values of normal cornea, at the site of corneal ulcer or abscess, and at a distant point of clear cornea during active and healed keratitis.
  
  
  RESULTS
  The mean densitometry value of normal corneas was 12.3 ± 2.4. In infectious keratitis, the densitometry values were greatest at the site of the active infection and significantly more than in controls. The densitometry values at the points of clear cornea furthest away from the site of infection also were significantly higher than in controls during active disease, but failed to return to normal values, despite complete resolution of infection. The density of the infiltrates was much higher than that of residual scars after healing of ulcers. No correlation was found between the pachymetry and the densitometry values.
  
  
  CONCLUSIONS
  Densitometry of active infectious corneal infiltrates is more than that resulting from the corneal scarring after healing. Persistent increase in density of clear cornea furthest away from the focus of corneal infection suggests that the host response extends beyond the immediate area of infection and indeed may occur through the entire cornea. These changes persist beyond 4 weeks of healing, which was the duration of follow-up of this study. Densitometry can be used as an objective measure of the corneal response to infection and to monitor response to therapy.
authors: School of Clinical Sciences, Division of Ophthalmology and Visual Sciences, Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom.
authors: Ahmad Muneer
authors: AM
authors: Otri
authors: Usama
authors: U
authors: Fares
authors: Mouhamed A
authors: MA
authors: Al-Aqaba
authors: Harminder S
authors: HS
authors: Dua
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002452:Cell Count; D003315:Cornea / Q000166:cytology / Q000473:pathology*; D003320:Corneal Ulcer / Q000175:diagnosis* / Q000382:microbiology; D003720:Densitometry; D003941:Diagnostic Techniques, Ophthalmological; D015818:Eye Infections, Bacterial / Q000175:diagnosis* / Q000382:microbiology; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000295:instrumentation; D011446:Prospective Studies; D012016:Reference Values; D014945:Wound Healing; D055815:Young Adult