Multifocal Intraocular Lens Implantation After Conductive Keratoplasty Using A Four-Step Corneal Topography Screening Protocol

Conductive keratoplasty (CK) is a non-ablative refractive procedure that was widely performed in the early 2000s for presbyopia and low hyperopia. However, long-term refractive regression and corneal irregularity after CK raise concerns regarding the suitability of multifocal intraocular lenses(IOLs) in subsequent cataract surgery. Because multifocal IOLs are sensitive to preexisting corneal aberrations, post-CK eyes are often considered poor candidates. This report describes the successful bilateral implantation of diffractive trifocal toric IOLs in a post-CK eye using a structured four-step corneal topography screening protocol.

Single-center case report conducted at The University of Osaka Hospital in Japan

A 74-year-old woman with bilateral cataracts had undergone CK (eight spots per eye) approximately 20 years earlier and laser iridotomy for narrow angles. She desired spectacle independence with priority for near vision and was not highly concerned about glare or halos.Preoperative corrected distance visual acuity was 20/40 in the right eye and 20/50 in the left eye. Manifest refraction was +0.75 D sphere with −1.00 D cylinder at 80° in the right eye and +0.75 D sphere with −0.50 D cylinder at 130° in the left eye. Corneal tomography and optical biometry were performed using swept-source anterior segment OCT and optical biometry. Candidacy for a diffractive trifocal toric IOL was assessed using a structured four-step corneal screening protocol (Goto et al, Ophthalmology 2021) evaluating higher-order aberrations (HOAs), corneal symmetry, regularity of astigmatism, and spherical aberration.HOAs were < 0.30 μm, corneal shape was symmetric without focal irregularity, astigmatism was regular and centrally located, and spherical aberration was within an acceptable range.IOL power was calculated using the Barrett Universal II formula, not the Barrett True-K formula. Surgery was uneventful, and a trifocal toric IOL was implanted in both eyes. At 3 months, corrected distance visual acuity was 20/20 in both eyes. Binocular uncorrected acuity was 20/16 at distance, 20/22 at 70 cm, and 20/25 at 40 cm. Mild halos were reported without bothersome glare, and no complications occurred.

This case demonstrates that satisfactory visual outcomes with diffractive trifocal toric IOLs can be achieved in eyes with prior CK when a systematic corneal topography- and tomography-based screening protocol is applied. Careful evaluation of corneal regularity, higher-order aberrations, astigmatism, and spherical aberration is essential for appropriate patient selection. Structured corneal assessment may expand the indications for multifocal IOL implantation even in post-refractive surgery eyes traditionally considered high risk.