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Multifocal IOL Power Calculation Using the Barrett True-K Formula After Radial Keratotomy: A Case Report

Year: 2026

Type: article

Abstract: Purpose: To report the clinical utility of the Barrett True-K formula in predicting multifocal intraocular lens (IOL) power in a patient with corneal deformation caused by radial keratotomy (RK), where postoperative refractive power prediction is challenging.Case summary: A 61-year-old male who underwent RK 30 years ago presented for cataract surgery. Slit-lamp examination showed eight RK incisions in each eye. Refractive error was +3.25 D sph; -1.75 D cyl, axis 70 in the right eye and +2.75 D sph; -1.00 D cyl, axis 110 in the left. Uncorrected visual acuity was 0.32 in the right eye and 0.63 in the left. IOL power was calculated using the Barrett True-K formula on the IOLMaster 700, with a target refraction of -0.25 D, and a multifocal IOL was implanted. Six months after cataract surgery, both eyes achieved a fraction close to emmetropia, with best corrected visual acuity of 0.63 in the right eye and 1.0 in the left. No significant refractive shifts or other complications were observed during surgery or 6-month follow-up.Conclusions: The Barrett True-K formula, which measures the actual corneal refractive power to compensate for corneal deformation, is expected to be clinically useful for multifocal IOL implantation during cataract surgery in eyes after RK.

Source: Journal of the Korean Ophthalmological Society

DOI: 10.3341/jkos.2026.67.2.67

Authors: Ji Hoon Ban, Myung Ho Cho, Jae Hyun Kim, Jong Soo Lee

Institutions: Pusan National University Hospital, Inje University Busan Paik Hospital

Language: English

Topic: Intraocular Surgery and Lenses

Subfield: Ophthalmology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: diamond

Funder: Pusan National University