Comparison of optical biometry and applanation ultrasound measurements of the axial length of the eye

Purpose: To investigate the relationship between optical biometry and applanation ultrasound measurement of the axial length of the eye. Materials and 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, correlationand 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). Conclusion: Optical biometry and applanation ultrasound measurements of axial length correlate well. However, optical biometry is preferable in short eyes.