IMPLANTATION OF A SMALL APERTURE INTRAOCULAR LENS IN AN EYE WITH IRREGULAR CORNEA AND HIGHER ORDER ABERRATIONS: A CASE SERIES

Corneas with complex optical aberrations pose a major challenge in cataract surgery. The implantation of small aperture intraocular lenses (IOLs) with the pinhole effect not only extends the depth of focus but also helps to minimize the effects of ocular aberrations and thus improve the quality of vision.

To evaluate visual outcomes and patients’ satisfaction following the implantation of a small aperture intraocular lens (IC-8® Apthera™ IOL, Bausch + Lomb Surgical) in patients with highly irregular astigmatism due to previous corneal surgery: pterygium excision, penetrating keratoplasty and keratoconus.

Unidade Local de Saúde Almada Seixal, Almada, Portugal

Case series with patients with cataract and irregular corneal astigmatism caused by previous corneal surgery. The study protocol included a baseline assessment and follow-up examinations at one day, one week, and one month after surgery. Exclusion criteria included pseudoexfoliation, unstable zonules, progressive ectasia, reduced endothelial cell count (<1800 cells/mm²), central corneal opacity, macular pathology, glaucoma, and functional monocularity. Patients’ evaluation included best-corrected visual acuity (BCVA), slit-lamp biomicroscopy, Goldmann applanation tonometry, corneal Scheimpflug tomography (Pentacam HR; Oculus Optikgeräte GmbH), and optical coherence tomography (Zeiss® CIRRUS HD-OCT 5000). Each patient underwent a 30-2 Humphrey visual field test postoperatively.

Primary outcomes were BCVA, subjective visual function, and visual field evaluation.

This case series included eight patients: four with history of recurrent pterygium surgery, two with previous penetrating keratoplasty and two with paracentral corneal opacities due to keratoconus. Mean BCVA improved from 0.5 to 0.2 logMAR one month after surgery. All patients reported subjective improvement in vision-related health and expressed their satisfaction through their answers to the VFQ-25 questionnaire. Throughout the follow-up examinations, visualization of the posterior segment was always possible. The mask of the IC-8 lens only extends up to 3.23 mm, leaving the peripheral portion of the IOL free and allowing unobstructed visualization of the peripheral retina. At 1 month follow-up, the Humphrey 30-2 visual field tests showed no signs of shrinkage or defects. No adverse events occurred during the follow- up.

The IC-8 lens is an effective solution for improving visual acuity in patients with irregular corneas and higher order aberrations (HOAs). The design of the lens, which utilizes the pinhole effect and reduces HOAs, enhances the quality of vision without compromising the retinal fundus visualization or visual field. Patients also report subjective improvements in their vision and confidence in daily activities.