Purpose: To compare and contrast axial length (AL) measurements assessed by ultrasound biometry and optical biometry.
Setting: Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.
Methods: Optical biometry and ultrasound biometry were performed in 360 eyes to measure AL.
Results: In eyes with a clear-appearing crystalline lens, there was a statistically significant median difference in AL measurements between the 2 methods in eyes with a normal or long length. In eyes with cataract, there was a statistically significant median difference in AL measurements in eyes with a normal or short length. In these cases, optical biometry produced larger readings than ultrasound biometry. In eyes with a posterior chamber intraocular lens, there was no statistically significant difference between the 2 methods in eyes of all lengths. In all eyes, the 2 methods produced reliable measurements.
Conclusions: These results show that optical biometry and ultrasound applanation biometry give statistically significant differences in AL measurement in patients with cataract and normal lenses. In these cases, optical biometry provided clinically relevant larger values than ultrasound applanation. Optical biometry provides an alternative to ultrasound biometry. However, ultrasound biometry may be indicated in certain complex cases.