Abstract
Purpose: :
To ascertain whether ultrasound biometry (A-scan) or partial coherence interferometry (IOL Master) provides a more accurate prediction of refractive outcomes in cataract surgery. We started with the hypothesis that the 2 technologies are equivalent.
Methods: :
This was a retrospective medical record review of patients who underwent cataract surgery with the IOL Master and ultrasound biometry from October 2006 to October 2008. The mean axial length and predicted refraction for each modality was compared. The mean difference between the prediction with each technology and the final spherical equivalent was compared. All patients who had complications related to the cataract surgery were excluded.
Results: :
Seventy-four eyes of 60 patients met the inclusion criteria. The mean age was 69 years (range 28 to 92 years) and 67% were female. The mean axial length was 23.60 for ultrasound biometry and 23.73 for the IOL Master. The mean of the difference between predicted refraction and final spherical equivalent was 0.42 D for ultrasound biometry and 0.45 D for the IOL Master. The prediction of postoperative refraction was within a difference of 1 D from the final spherical equivalent for 71 eyes (96%) for both ultrasound biometry and the IOL Master. A total of 49 eyes (66.2%) were within 0.50 D of the final spherical equivalent using ultrasound biometry, and 46 eyes (62.2%) were within this range with the IOL Master. Twenty-nine eyes (39.2%) were within a range of 0.25 D of the final spherical equivalent using IOL Master predictions, and 27 eyes (36.5%) were within the same range with the ultrasound biometry predictions. Overall, ultrasound biometry was more accurate in predicting the post-operative refraction in 60% of eyes.
Keywords: intraocular lens • cataract