Evaluation of total keratometry and its accuracy for intraocular lens power calculation in eyes after corneal refractive surgery.

PURPOSE

To compare the accuracy of total keratometry (TK) and standard keratometry (K) from a swept-source optical coherence tomography biometer for intraocular lens (IOL) power calculation in eyes with previous corneal refractive surgery.

SETTING

Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.

DESIGN

Retrospective case series.

METHODS

The differences between the TK and K and their association with K were assessed. For IOL power calculation, combinations of 1) K with Haigis, Haigis-L, and Barrett True-K, and 2) TK with Haigis (Haigis-TK) were used. The mean absolute error (MAE) and the percentages of eyes within prediction errors of ± 0.50 diopters (D), ± 1.00 D, and ± 2.00 D were calculated.

RESULTS

The study comprised 129 eyes. For Haigis, Haigis-L, Barrett True-K, and Haigis-TK, respectively, the MAEs were 0.72 D, 0.61 D, 0.54 D, and 0.50 D in the myopic laser in situ keratomileusis (LASIK)/photorefractive keratectomy (PRK) group, and 0.74 D, 0.68 D, 0.71 D, and 0.70 D in hyperopic LASIK/PRK group. For the radial keratotomy (RK) eyes, the MAEs were 0.66 D, 0.71 D, and 0.72 D for the Haigis, Barrett True-K, and Haigis-TK formulas, respectively. In the myopic LASIK/PRK group, the Barrett True-K and Haigis-TK produced significantly lower MAEs than did Haigis (P < .05). In the hyperopic LASIK/PRK and RK groups, there were no significant differences between the formulas in MAEs and percentages of eyes within the above prediction errors.

CONCLUSIONS

The performance of the combination of Haigis and TK in refractive prediction was comparable with Haigis-L and Barrett True-K in eyes with previous corneal refractive surgery.