Repeatability and reproducibility of biometry and keratometry measurements using a noncontact optical low-coherence reflectometer and keratometer.

PURPOSE

To evaluate the repeatability, reproducibility, or both of the biometry and keratometry measurements obtained by a new optical low-coherence reflectometer and keratometer (Lenstar LS 900, version 1.10; Haag-Streit).

DESIGN

Prospective, comparative, observational study.

SETTING

Private practice, Lynwood, California, and Santa Monica, California.

STUDY POPULATION

The measurements of the second eye to be operated on of 37 patients between October 2010 and January 2011 were analyzed.

OBSERVATION PROCEDURE

The axial length, central corneal thickness, aqueous depth, anterior chamber depth, crystalline lens thickness, white-to-white corneal diameter, as well as the keratometric readings at the flattest meridian, the steepest meridian, the average K, the amount of astigmatism, and the minus astigmatic cylinder axis were measured before surgery on the patient's first eye and were repeated 1 month later before the second eye surgery. main outcome measures: The repeatability and reproducibility of the biometry and keratometry measurements.

RESULTS

Intrasession repeatability and intersession reproducibility were excellent with a very low coefficient of variation and high interclass correlation coefficients for all measured parameters. Bland-Altman plots show good correlation for axial length measurements (95% limits of agreement ranging from -0.056 to +0.04 mm), anterior chamber depth (-0.22 to +0.18 mm), crystalline lens thickness (-0.21 to +0.27 mm), corneal diameter (-0.28 to +0.24 mm), average keratometric readings (-0.56 to +0.47 diopters), and amount of astigmatism (-0.58 to +0.40 diopters).

CONCLUSIONS

The precision of the measurements obtained by the new optical reflectometer and keratometer is extremely high.