Which keratometer is most reliable for correcting astigmatism with toric intraocular lenses?
OBJECTIVE
To evaluate the accuracy of preoperative keratometers used in cataract surgery with toric intraocular lens (IOL).


METHODS
Twenty-five eyes received an AcrySof toric IOL implantation. Four different keratometric methods, a manual keratometer, an IOL master, a Pentacam and an auto keratometer, were performed preoperatively in order to evaluate preexisting corneal astigmatism. Differences between the true residual astigmatism and the anticipated residual astigmatism (keratometric error) were compared at one and three months after surgery by using a separate vector analysis to identify the keratometric method that provided the highest accuracy for astigmatism control.


RESULTS
The mean keratomeric error was 0.52 diopters (0.17-1.17) for the manual keratometer, 0.62 (0-1.31) for the IOL master, 0.69 (0.08-1.92) for the Pentacam, and 0.59 (0.08-0.94) for the auto keratometer. The manual keratometer was the most accurate, although there was no significant difference between the keratometers (p > 0.05). All of the keratometers achieved an average keratometric error of less than one diopter.


CONCLUSIONS
Manual keratometry was the most accurate of the four methods evaluated, although the other techniques were equally satisfactory in determining corneal astigmatism.
Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.
Minwook
M
Chang
Su-Yeon
SY
Kang
Hyo Myung
HM
Kim
D000704:Analysis of Variance; D001251:Astigmatism / Q000150:complications / Q000601:surgery*; D002387:Cataract Extraction; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular / Q000379:methods*; D007910:Lenses, Intraocular; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D012029:Refraction, Ocular; D015203:Reproducibility of Results; D016896:Treatment Outcome; D014792:Visual Acuity