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Predicting the refractive outcome after cataract surgery: the comparison of different IOLs and SRK-II v SRK-T
  1. M J Elder
  1. Department of Ophthalmology, Christchurch School of Medicine, University of Otago
  1. Correspondence to: Associate Professor Mark Elder, Department of Ophthalmology, Christchurch Hospital, PO Box 4710, Christchurch, New Zealand


Aim: To determine any differences between the predictive abilities of the IOL calculation formulas of SRK-II and SRK-T and to compare these using two different IOL types.

Methods: A prospective, consecutive, single surgeon clinical trial was conducted on 400 consecutive patients who received routine, standardised phacoemulsification cataract surgery. 200 had cataract surgery and had the Alcon MZ30BD, a 5.5 mm one piece PMMA IOL, and another 200 cases used the Chiron C11UB, a silicone plate haptic IOL. The data used optimised A-constants. The measures were preoperative axial length and keratometry, IOL implanted, and refractive error at 4–6 weeks postoperatively.

Results: There was no significant difference between the predictive abilities of SRK-II or SRK-T. For the Alcon and Chiron lens respectively, prediction errors using SRK-II were <0.5 dioptres in 58% and 70% and for <1.0 dioptres in 84% and 92%. These differences were statistically significant (χ2, p=0.02).

Conclusion: There are differences in the predictability of refractive outcomes between intraocular lens styles.

  • refractive outcome
  • cataract surgery
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