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- Title
Evaluation of Different Corneal Powers Measured by Corneal Tomography in Intraocular Lens Power Calculation.
- Authors
Abd EL-moneam, Heba A.; El-maamon, Tarek A.; Eliwa, Tamer F. M.; Abd EL-aziz, Mohammad H.
- Abstract
Background: Corneal power measurement is essential for IOL power calculation. Conventional keratometry measures the anterior corneal surface using a standard keratometric index without measuring the posterior corneal surface. Schiempflug imaging have added the ability to measure posterior corneal surface which may affect IOL power calculation and postoperative refraction. Purpose: To evaluate different keratometric measurements including Simulated keratometry (SimK), true net power (TNP), total corneal refractive power (TCRP) and equivalent K reading (EKR) obtained from corneal tomography in IOL power calculation and compare the predicted refraction of calculated IOL power with postoperative subjective refraction. Materials and Methods: Sixty-five cataractous eyes were included in this prospective interventional case series. Four corneal power measurements using Pentacam AXL were analyzed: SimK over 3mm, TNP over 4mm, TCRP over 3mm and EKR over 4.5mm. The IOL power was calculated using Barrett Universal II formula. Results: No statistically significant difference between SimK and EKR (p- value=1.000) while TNP and TCRP were statistically significantly higher than SimK (p-value<0.001) with mean difference 1.2+/-0.2D and 0.67+/-0.34D respectively. The mean prediction error of refractive outcome was -0.006+/-0.32D for SimK, -0.02+/- 0.5D for EKR, 1.08+/-0.4D for TNP and 0.56+/-0.46D for TCRP. Conclusion: Corneal power measurements using SimK and EKR displayed comparable accuracy in IOL power calculation and postoperative refraction while TNP and TCRP were far away.
- Subjects
INTRAOCULAR lenses; CORNEA; PHOTOREFRACTIVE keratectomy; TOMOGRAPHY; REFRACTIVE errors
- Publication
QJM: An International Journal of Medicine, 2024, Vol 117, pi165
- ISSN
1460-2725
- Publication type
Article
- DOI
10.1093/qjmed/hcae070.382