Enhancing Vision With Small Aperture Extended Depth of Focus IOLs and Adjunctive PRK in Patients With Keratoconus

EP: 1.Expanding the Depth of Focus With IC-8 Apthera IOL

EP: 2.Achieving Functional Vision in Patients Seeking Freedom From Glasses

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EP: 3.Enhancing Vision With Small Aperture Extended Depth of Focus IOLs and Adjunctive PRK in Patients With Keratoconus

Enhancing Vision With Small Aperture Extended Depth of Focus IOLs and Adjunctive PRK in Patients With Keratoconus

This case presents a 50-year-old male patient with a history of keratoconus who had previously undergone corneal cross-linking and topography-guided photorefractive keratectomy (PRK) in his left eye. Before proceeding with any premium IOL consideration, the surgeon verified keratoconus stability by comparing Pentacam measurements from 2021 to 2024, confirming that Kmax values remained stable and corneal thickness had not decreased, indicating successful stabilization from the cross-linking procedure. The patient's macula appeared pristine, which is particularly crucial for small aperture lenses that direct concentrated light to the foveal region.

Preoperative measurements revealed discrepancies between different topographic devices, with the Pentacam showing 0.3 D of astigmatism while the Sirius detected 1.63 D in the central 3-mm zone. Despite the IC-8's ability to mask up to 1.75 D of astigmatism, the surgeon targeted -0.66 diopters for this non-dominant eye to optimize the defocus curve, extending reading ability while maintaining good distance and intermediate vision. Post-operatively, the patient achieved 20/20 uncorrected vision and the lens successfully masked astigmatism, but he experienced significant ghosting due to quality issues related to central corneal astigmatism that was potentially increased by the cataract incision.

The case was resolved through adjunctive photorefractive keratectomy (PRK) targeting the central astigmatism with –1.5 D at 4 degrees axis, which eliminated the quality issues while maintaining the same 20/20 and J1 visual acuity. This case emphasizes 2 critical takeaways for small aperture IOL success: first, the importance of controlling central 3-mm-zone astigmatism and irregularities for optimal visual quality, and second, ensuring nighttime pupil size remains under 5 mm to prevent glare issues from the carbon nanoparticle ring. The IC-8 Apthera proves particularly valuable for patients with peripheral corneal irregularities, scars, and those adapted to monovision, but it requires careful attention to central corneal optics and pupil dynamics for optimal outcomes.