Influence of corneal spherical aberration on prediction error of the Haigis-L formula

Abstract

The purpose of this study is to investigate the relationships between corneal asphericity and Haigis-L formula prediction errors in routine cataract surgery after refractive surgery for myopic correction. This retrospective study included 102 patients (102 eyes) with a history of previous PRK or LASIK and cataract surgery. Axial length, anterior chamber depth, and central corneal power were measured using the optical biometer. On the anterior corneal surface, Q-value, spherical aberration, and ecentricity at 6.0 and 8.0 mm were measured using a rotating Scheimpflug camera. The postoperative refractive outcome at 6 months, mean error, and mean absolute error were determined. Correlation tests were performed to determine the associations between pre-cataract surgery data and the prediction error. The Q-values for 6.0 and 8.0 mm corneal diameter were 1.57 ± 0.70 (range: 0.03~3.44), and 0.82 ± 0.5 (range: −0.10~−2.66). The spherical aberration for 6.0 and 8.0 mm diameter was 1.16 ± 0.39 µm (range: 0.24~2.08 µm), and 3.69 ± 0.87 µm (range: 0.91~5.91 µm). eccentricity for 6.0 and 8.0 mm diameter was − 1.22 ± 0.31 (range: −1.85 to −0.17), and −0.82 ± 0.39 (range: −1.63 to 0.32). The spherical aberration for 8.0 mm cornea diameter showed the highest correlations with the predicion error (r = 0.750; p < 0.001). When the modified Haigis-L formula considering spherical aberration for 8.0 mm produced smaller values in standard deviation of mean error (0.45D versus 0.68D), mean absolute error (0.35D versus 0.55D), and median absolute error (0.31D versus 0.51D) than the Haigis formula. Corneal asphericity influences the predictive accuracy of the Haigis-L formula. The accuracy was enhanced by taking into consideration the corneal spherical aberration for the 8.0 mm zone at precataract surgery state. open Scientific RepoRtS | (2020) 10:6445 | https://doi.

The influence of corneal ablation patterns on prediction error after cataract surgery in post-myopic-LASIK eyes

“…Previous investigations found that corneal asphericity was associated with prediction errors after cataract surgery in post-LASIK eyes, indicating the potential influence of corneal ablation patterns on the predictive accuracy of IOL power calculation formulas [6,7]. In our clinical practice, we looked carefully into patients with extreme refractive errors and noticed that the amount of ablation and ablation zone decentration may have a great influence on IOL power calculation of these eyes.…”

Effect of Sodium Fluorescein Strip Application on Cornea Parameters Commonly Used in Laser-assisted in-situ Keratomileusis

“…Corneal asphericity at the anterior corneal surface is negative and increases from the center to the periphery. [14] Esraa El-Mayah et al previously suggested that the spherical aberration at 6.0 mm is affected by the ablation pro le method, but the Q-value at 8.0 mm is a parameter that could predict ablation volume or ablation depth relatively independently of ablation pro le; [15] as such, the measurement of the Q-value in the 8 mm zone was investigated in our study. In LASIK, monovision is a method of presbyopic correction, in which one eye is corrected for distance vision and the other eye for near vision, and this procedure is based on Q factor modulation.…”

Associations between anterior segment biometry and high axial myopia in 3438 cataractous eyes in the Chinese population

“…To date, the Panacea formula is the only formula that enables cataract surgeons to enter the Q value [ 27 ]. In a study by Woong-Joo Whang on the optimization of IOL formulas, the accuracy of the Haigis-L formula was enhanced after taking into consideration the Q value at preoperative stage [ 29 ]. Therefore, we recommend creating a new IOL power formula in which Q value, WTW, ACD, and CRP are simultaneously considered.…”