title: Comparison of optical biometry and applanation ultrasound measurements of the axial length of the eye.
abstract: OBJECTIVE
  To investigate the relationship between optical biometry and applanation ultrasound measurement of the axial length of the eye.
  
  
  METHODS
  This prospective study enrolled 55 (68 eyes) consecutive patients scheduled for cataract surgery at Dhahran Eye Specialist Hospital (DESH). Every eye underwent two measurements each with an optical biometer and with applanation ultrasound. Only patients with cataract and no other ophthalmic pathology or disease were enrolled. Comparison, correlation and repeatability of axial length with both devices were analyzed. Agreement between devices was evaluated. A regression formula to convert measurements between devices was investigated. A p value less than 0.05 was statistically significant.
  
  
  RESULTS
  There was strong repeatability (99.4%) and agreement (r = 0.987) between both devices (p < 0.001); the difference between devices was mainly in short eyes (p = 0.031).
  
  
  CONCLUSIONS
  Optical biometry and applanation ultrasound measurements of axial length correlate well. However, optical biometry is preferable in short eyes.
authors.affiliation: Optometry and Investigation Services, Dhahran Eye Specialist Hospital (DESH), P.O. Box 39455 Zip: 31942, Dhahran, Eastern Province, Saudi Arabia.
authors.forename: Fouad R
authors.initials: FR
authors.lastname: Nakhli
keywords: A-scan; Axial length; IOLMaster; Optical; Ultrasound