Total corneal refractive power and calculation of a spherical equivalent of an intraocular lens
DOI: 10.32364/2311-7729-2025-25-1-1
Yu.M. Petrosyan1,2, E.V. Boiko1–3, S.V. Shukhaev1, I.B. Litvin1,2
1St. Petersburg Branch of the S. Fyodorov Eye Microsurgery Federal State Institution, St. Petersburg, Russian Federation
2North West State Medical University named after I.I. Mechnikov, St. Petersburg, Russian Federation
3St. Petersburg State University, St. Petersburg, Russian Federation
Aim: to evaluate the calculation accuracy of a multifocal intraocular lens (mIOL) based on total corneal refractive power (TCRP) defined by ray tracing in 10 corneal zones using 10 formulas.
Patients and Methods: the study included 98 subjects who underwent femtolaser-assisted phaco (phacoemulsification) of cataract along with mIOL implantation and achieved target refraction at different distances. A retrospective mIOL calculation was performed according to OA-2000 and TCRP biometric data (zones from 0.5 mm to 5 mm in 0.5 mm increments) using 10 formulas (SRK/T, Holladay 1, Holladay 2, Haigis, Hoffer Q, Barrett 2 Universal, Olsen, Kane, EVO, and Hill RBF). Mean refractive prediction error (ME), its difference from zero, and algebraic median were calculated for each zone/formula combination. Moreover, the mean (MAE) and median (MedAE) absolute errors, as well as standard deviation (SD) were calculated for them after optimization of the constants.
Results: up to a 3.5 mm zone, all formulas give a hypermetropic error, and beginning with a 4.0 mm zone, a refractive prediction error begins to shift towards emmetropia with the best values in a 5.0 mm zone. An insignificant difference between predicted and actual refraction values was determined for most formulas in a 5.0 mm zone when centered on the pupil (except for the Haigis and Kane formulas). Most formulas demonstrate median values within ±0.1 in the peripheral zones. The maximum MAE values are demonstrated by the Barrett, Olsen, SRK/T, and EVO formulas. These formulas, as well as the Kane formula, showed high MedAE values. Low MAE values are determined for Holladay 2, Haigis, Hoffer Q, and Holladay 1 formulas (with the minimum values in zones of 4.0–5.0 mm). All formulas tend to decrease dispersion with an increase in a zone size; the best values are recorded for the Holladay 2, Haigis, Hoffer Q and Holladay 1 formulas in 4.0–5.0 mm zones. As the highest variance is reported in the Barrett, Olsen and SKR/T formulas for any data set, this implies a high instability of the calculations.
Conclusion: the most accurate preoperative calculation of a spherical equivalent of a mIOL using TCRP values is possible using the Holladay 1 formula in 4.0–5.0 mm zones. Holladay 2, Haigis, and Hoffer Q formulas are more efficient in 3.0–5.0 mm zones, while Kane, EVO, and Hill formulas are more efficient in 4.0–5.0 mm zones. The Barrett, Olsen and SKR/T formulas are not appropriate for use with TCRP data.
Keywords: spherical equivalent of intraocular lens, multifocal intraocular lens, keratotomography, total corneal refractive power, keratometry zone, cataract phacoemulsification.
For citation: Petrosyan Yu.M., Boiko E.V., Shukhaev S.V., Litvin I.B. Total corneal refractive power and calculation of a spherical equivalent of an intraocular lens. Russian Journal of Clinical Ophthalmology. 2025;25(1):2–8 (in Russ.). DOI: 10.32364/2311-7729-2025-25-1-1
About the authors:
Yurii M. Petrosyan — Ophthalmologist, St. Petersburg Branch of the S. Fyodorov Eye Microsurgery Federal State Institution; 21a, Yaroslav Gashek str., St. Petersburg, 192283, Russian Federation; postgraduate student of the Department of Ophthalmology, North West State Medical University named after I.I. Mechnikov; 41, Kirochnaya str., St. Petersburg, 191015, Russian Federation; ORCID iD 0000-0003-4081-0078
Ernest V. Boiko — Dr. Sc. (Med.) Professor, Honored Physician of the Russian Federation, Director, St. Petersburg Branch of the S. Fyodorov Eye Microsurgery Federal State Institution; 21a, Yaroslav Gashek str., St. Petersburg, 192283, Russian Federation; Head of the Department of Ophthalmology, North West State Medical University named after I.I. Mechnikov; 41, Kirochnaya str., St. Petersburg, 191015, Russian Federation; Professor of the Department of Otorhinolaryngology and Ophthalmology, St. Petersburg State University; 7–9, Universitetskaya emb., St. Petersburg, 199034, Russian Federation; ORCID iD 0000-0002-7413-7478
Sergei V. Shukhaev — C. Sc. (Med.), Ophthalmologist, St. Petersburg Branch of the S. Fyodorov Eye Microsurgery Federal State Institution; 21a, Yaroslav Gashek str., St. Petersburg, 192283, Russian Federation; ORCID iD 0000-0001-7047-615X
Irina B. Litvin — C. Sc. (Med.), Assistant Professor, Head of the Scientific and Educational Department, St. Petersburg Branch of the S. Fyodorov Eye Microsurgery Federal State Institution; 21a, Yaroslav Gashek str., St. Petersburg, 192283, Russian Federation; Assistant Professor of the Department of Ophthalmology, North West State Medical University named after I.I. Mechnikov; 41, Kirochnaya str., St. Petersburg, 191015, Russian Federation; ORCID iD 0000-0002-1549-3341
Contact information: Yurii M. Petrosyan, e-mail: petrosyan.yurij@yandex.ru
Financial Disclosure: no authors have a financial or property interest in any material or method mentioned.
There is no conflict of interest.
Received 18.03.2024.
Revised 10.04.2024.
Accepted 06.05.2024.
2. Куликов А.Н., Кокарева Е.В., Котова Н.А. Сравнение результатов биометрии глаза при использовании различных приборов. Тихоокеанский медицинский журнал. 2017;2:53–54. DOI: 10.17238/PmJ1609-1175.2017.2.53-55Kulikov A.N., Kokareva E.V., Kotova N.A. Comparison of the results of the eye biometrics using different instruments. Pacific Medical Journal. 2017;2:53–54 (in Russ.). DOI: 10.17238/PmJ1609-1175.2017.2.53-55
3. Aksoy M., Asena L., Güngör S.G. et al. Comparison of refractive outcomes using Scheimpflug Holladay equivalent keratometry or IOLMaster 700 keratometry for IOL power calculation. Int Ophthalmol. 2021;41:2205–2212. DOI: 10.1007/s10792-021-01781-6
4. Cooke D.L., Cooke T.L. Comparison of 9 intraocular lens power calculation formulas. J Cataract Refract Surg. 2016;42:1157–1164. DOI: 10.1016/j.jcrs.2016.06.029
5. Kane J.X., Van Heerden A., Atik A. et al. Intraocular lens power formula accuracy: comparison of 7 formulas. J Cataract Refract Surg. 2016;42:1490–1500. DOI: 10.1016/j.jcrs.2016.07.021
6. Melles R.B., Holladay J.T., Chang W.J. Accuracy of intraocular lens calculation formulas. Ophthalmology. 2018;125:169–178. DOI: 10.1016/j.ophtha.2017.08.027
7. Бойко Э.В., Винницкий Д.А. Сравнение зрительной реабилитации с применением трифокальных и бифокальных интраокулярных линз (обзор литературы). Офтальмохирургия. 2018;2:67–74. DOI: 10.25276/0235-4160-2018-2-67-74Boiko E.V., Vinnitskiy D.A. Rehabilitation of patients after implantation of bifocal and trifocal intraocular lens. Fyodorov Journal of Ophthalmic Surgery. 2018;2:67–74 (in Russ.). DOI: 10.25276/0235-4160-2018-2-67-74
8. Moschos M.M., Chatziralli I.P., Koutsandrea C. Intraocular lens power calculation in eyes with short axial length. Indian J Ophthalmol. 2014;62:692–694. DOI: 10.4103/0301-4738.129791
9. Киселева Т.Н., Оганесян О.Г., Романова Л.И. и др. Оптическая биометрия глаза: принцип и диагностические возможности метода. Российская педиатрическая офтальмология. 2017;12(1):35–42. DOI: 10.18821/1993-1859-2017-12-1-35-42Kiseleva T.N., Oganesyan O.G., Romanova L.I. et al. Optical biometry of the eye: the principle and the diagnostic potential of the method. Russian pediatric ophthalmology. 2017;12(1):35–42 (in Russ.). DOI: 10.18821/1993-1859-2017-12-1-35-42
10. Savini G., Barboni P., Carbonelli M., Hoffer K.J. Accuracy of corneal power measurements by a new Scheimpflug camera combined with Placido-disk corneal topography for intraocular lens power calculation in unoperated eyes. J Cataract Refract Surg. 2012;38(5):787–792. DOI: 10.1016/j.jcrs.2011.11.037
11. Куликов А.Н., Даниленко Е.В., Кожевников Е.Ю. Сравнение различных вариантов кератометрии у пациентов с роговичным астигматизмом. Российский офтальмологический журнал. 2022;15(2):84–92.Kulikov A.N., Danilenko E.V., Kozhevnikov E.Yu. Comparison of keratometry versions in patients with corneal astigmatism. Russian ophthalmological journal. 2022;15(2):84–92 (in Russ.). DOI: 10.21516/2072-0076-2022-15-2-supplement-84-92
12. Savini G., Barboni P., Carbonelli M., Hoffer K.J. Accuracy of Scheimpflug corneal power measurements for intraocular lens power calculation. J Cataract Refract Surg. 2009;35(7):1193–1197. DOI: 10.1016/j.jcrs.2009.02.031
13. Seo K.Y., Im C.Y., Yang H. et al. New equivalent keratometry reading calculation with a rotating Scheimpflug camera for intraocular lens power calculation after myopic corneal surgery. J Cataract Refract Surg. 2014;40(11):1834–1842. DOI: 10.1016/j.jcrs.2013.11.044
14. Wang Q., Savini G., Hoffer K.J. et al. Comprehensive Assessment of the Precision and Agreement of Anterior Corneal Power Measurements Obtained Using 8 Different Devices. PLoS One. 2012;7(9):e45607. DOI: 10.1371/journal.pone.0045607
15. Savini G., Hoffer K.J., Schiano L.D., Ducoli P. Simulated Keratometry Versus Total Corneal Power by Ray Tracing. Cornea. 2017;36(11):1368–1372. DOI: 10.1097/ico.0000000000001343
16. Mukhija R., Gupta N. Advances in anterior segment examination. Community Eye Health. 2019;32(107):S5. PMID: 32123483
17. Kanclerz P., Khoramnia R., Wang X. Current developments in corneal topography and tomography. Diagnostics. 2021;11(8):1466. DOI: 10.3390/diagnostics11081466
18. Fan R., Chan T.C., Prakash G., Jhanji V. Applications of corneal topography and tomography: a review. Clin Exp Ophthalmol. 2018;46(2):133–146. DOI: 10.1111/ceo.13136
19. Savini G., Hoffer K.J. Pentacam equivalent K-reading [letter]. J Refract Surg. 2010;26:388–389. DOI: 10.3928/1081597X-20100423-01
20. Savini G., Barboni P., Carbonelli M., Hoffer K.J. Comparison of methods to measure corneal power for intraocular lens power calculation using a rotating Scheimpflug camera. J Cataract Refract Surg. 2013;39(4):598–604. DOI: 10.1016/j.jcrs.2012.11.022
21. Saad E., Shammas M.C., Shammas H.J. Scheimpflug corneal power measurements for intraocular lens power calculation in cataract surgery. Am J Ophthalmol. 2013;156(3):460–467. DOI: 10.1016/j.ajo.2013.04.035
22. Næser K., Savini G., Bregnhøj J.F. Corneal powers measured with a rotating Scheimpflug camera. Br J Ophthalmol. 2016;100(9):1196–1200. DOI: 10.1136/bjophthalmol-2015-307474
This work is licensed under a Creative Commons «Attribution» 4.0 License.
