Premium
A clinical comparison of optical and ultrasonic pachometry
Author(s) -
Nissen Jørgen,
Hjortdal Jesper Ø.,
Ehlers Niels,
FrostLarsen Kim,
Sörensen Torben
Publication year - 1991
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.1991.tb04857.x
Subject(s) - ultrasonic sensor , ultrasound , ophthalmology , linear correlation , significant difference , positive correlation , cornea , materials science , medicine , biomedical engineering , mathematics , radiology , statistics
Central corneal thickness (CCT) of normal and oedematous corneae was measured in a study comparing a modified Haag‐Streit optical pachometer and an ultrasonic pachometer (Teknar Ophthasonic®, preset velocity 1630 m/s). Sixty‐eight patients were examined before and after cataract extraction with implantation of an anterior chamber lens. Mean values of CCT before operation were 531 ± 4.9 (sem) μm by optical pachometry and 524 ± 4.7 μm when measured by ultrasound (not significantly different). On the first post‐operative day the values were 618 ± 8.4 and 602 ± 7.6 μm for optical and ultrasonic measurements, respectively (significantly different, 2 P < 0.001). Correlation analysis showed a high dependence between the methods with coefficients of correlation being 0.955 before and 0.958 after the operation. Linear regression analysis revealed small, but significant differences between the techniques. The difference between the two methods increased with increasing corneal hydration, whereas it could not be ascribed to sex, age, or intraocular pressure. It is concluded that for clinical purposes optical and ultrasonic pachometry techniques are comparable.