Effect of fixation stability during biometry measurements on refractive prediction accuracy in highly myopic eyes.

PURPOSE: To assess the effect of preoperative biometry fixation stability on postoperative refractive errors in highly myopic cataractous eyes.

SETTING: Eye and ENT Hospital of Fudan University, Shanghai, China.

DESIGN: Prospective cohort study.

METHODS: Eyes of highly myopic patients and emmetropic controls were included. Routine ophthalmologic examinations and measurement of fixation stability in the 63% and 95% bivariate contour ellipse areas (BCEAs) were conducted preoperatively. The refractive error from prediction was calculated 1 month postoperatively with the SRK/T and Holladay 1 formulas. Univariate and multivariable analyses were performed to identify the factors associated with postoperative refractive errors.

RESULTS: The refractive errors were more widely distributed in the 45 highly myopic eyes than in the 40 emmetropic control eyes: SRK/T, +0.15 diopter [D] ± 0.80 [SD] and -0.16 ± 0.35 D, respectively; Holladay 1, +0.54 ± 0.79 D and -0.23 ± 0.34 D, respectively. In the highly myopic group, 63% BCEA was correlated with axial length (AL) (P = .021) and posterior subcapsular opacity grade (P = .040). With both formulas, refractive errors and absolute refractive errors were positively correlated with 63% BCEA: SRK/T, P = .010 and P = .001, respectively; Holladay 1, P = .006 and P = .003, respectively. Backward multiple linear regression analysis showed that with both formulas, AL and 63% BCEA were significantly associated with postoperative refractive errors.

CONCLUSION: Poor preoperative biometry fixation stability correlated with long AL and severe posterior subcapsular opacity contributed to significant deviation of refractive errors after cataract surgery in highly myopic eyes.