Intraocular lens calculation after refractive surgery for myopia: Haigis-L formula
Accepted 20 June 2008.
Purpose
To describe the Haigis-L formula for the calculation of intraocular lenses (IOLs) after refractive laser surgery for myopia based on current biometry and keratometry and present clinical results.
Setting
University Eye Hospital, Wuerzburg, Germany, and various clinics and private practices.
Methods
The basic concepts of the new algorithm were described and summarized. The Haigis formula was analyzed with respect to its usability for eyes after laser surgery for myopia and modified accordingly. Correction curves for IOLMaster keratometry were derived from previous studies. The new formula was checked using the postoperative results of 187 cataract procedures in which 32 IOL types were implanted by 57 surgeons. Input data were current IOLMaster biometry as follows: axial length (AL), anterior chamber depth (ACD), and keratometry (corneal radii) measurements.
Results
Before IOL surgery, the mean spherical equivalent was −7.60 diopters (D) ± 3.90 (SD) (range −20.00 to −1.25 D); the mean AL, 27.02 ± 2.01 mm (range 23.09 to 35.32 mm); the mean ACD, 3.52 ± 0.36 mm (range 2.43 to 4.39 mm); and the mean of the measured corneal radii, 8.70 ± 0.60 mm (range 7.28 to 10.96 mm). The mean arithmetic refractive prediction error was −0.04 ± 0.70 D (range −2.30 to +2.40 D) and the median absolute error, 0.37 D (range +0.01 to +2.40 D). The percentages of correct refraction predictions within ±2.00, ±1.00, and ±0.50 D were 98.4%, 84.0%, and 61.0%, respectively.
Conclusions
The new formula would produce promising results in eyes without refractive history. Its refractive predictability fulfills the current criteria for normal eyes.
From the University Eye Hospital, Wuerzburg, Germany
Corresponding author: Wolfgang Haigis, MS, PhD, University Eye Hospital, 11, Josef-Schneider-Strasse, D-97080 Wuerzburg, Germany.
The author has no financial or proprietary interest in any material or method mentioned.
Presented in part at the ASCRS Symposium on Cataract, IOL and Refractive Surgery, San Francisco, California, USA, March 2006.
ABSTRACT