| ORIGINAL ARTICLE |
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| Year : 2016 | Volume
: 23
| Issue : 1 | Page : 122-128 |
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Accuracy of corneal power measurements for intraocular lens power calculation after myopic laser In situ Keratomileusis
Hany A Helaly, Mohammad A. M. El-Hifnawy, Mohamed Shafik Shaheen, Amr F Abou El-Kheir
Department of Ophthalmology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
Correspondence Address:
Hany A Helaly
30, Roshdy Street, Roshdy, Alexandria
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0974-9233.171755
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Purpose: To evaluate the accuracy of corneal power measurements for intraocular lens (IOL) power calculation after myopic laser in situ keratomileusis (LASIK).
Methods: The study evaluated 45 eyes with a history of myopic LASIK. Corneal power was measured using manual keratometry, automated keratometry, optical biometry, and Scheimflug tomography. Different hypothetical IOL power calculation formulas were performed for each case.
Results: The steepest mean K value was measured with manual keratometry (37.48 ± 2.86 D) followed by automated keratometry (37.31 ± 2.83 D) then optical biometry (37.06 ± 2.98 D) followed by Scheimflug tomography (36.55 ± 3.08). None of the K values generated by Scheimflug tomography were steeper than the measurements from the other 3 instruments. Using equivalent K reading (EKR) 4 mm with the Double-K SRK/T formula, the refractive outcome generated 97.8% of cases within ± 2 D, 80.0% of cases within ± 1 D, and 42.2% of cases within ± 0.5 D. The best combination of formulas was “Shammas-PL + Double-K SRK/T formula using EKR 4 mm.”
Conclusion: Scheimflug tomography imaging using the Holladay EKR 4 mm improved the accuracy of IOL power calculation in post.LASIK eyes. The best option is a combination of formulas. We recommended the use the combined “Shammas-PL ± Double-K SRK/T formula using EKR 4 mm”h for optical outcomes. |
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