Abstract
Purpose: :
To compare the accuracy of intraocular lens (IOL) power calculation formulas: SRK2, SRK-T, Hoffer Q, Holladay1, in eyes with long and short axial length (AL)
Methods: :
A retrospective chart review was performed for the patients who underwent phacoemulsification with IOL insertion into the bag. The eyes with AL shorter than 22 mm or longer than 25 mm were involved. Eyes with intraoperative complications and missing postoperative manifest refraction were excluded. Preoperative biometric data was used to obtain a preoperative predictive value for a given IOL in each formula. Then the predictive value was compared to the postoperative refraction and analyzed in stratification of short AL (<22 mm), medium-long AL (25< to 26 mm) and long AL (>26 mm).
Results: :
Ninety four eyes in 68 patients for AL shorter than 22 mm and ninety nine eyes in 82 patients for AL longer than 25 mm were involved. There was no significant difference between the prediction and the manifest refraction for any of the four formulas in short and medium-long AL. In long AL, however, more predictive errors in refraction were shown with SRK2 than with other three formulas.
Conclusions: :
Third generation formulas: SRK-T, Hoffer Q and Holladay1, function equally well in long and short eyes in contrast to SRK2 formula which performs well in short AL but shows more prediction errors in long AL.
Keywords: intraocular lens • cataract • refraction