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14 | EYEWORLD | FALL 2024 ASCRS NEWS EYEWORLD JOURNAL CLUB by Ryan Wallace, MD,* Sanchay Gupta, MD, MBA,* Uma Balakrishnan, MD,* Cullen Eye Institute residents, Masih Ahmed, MD, Residency Program Director *All authors contributed equally to this work. HOAs up to the 6th order with a natural phot- opic pupil size and pupil aperture of 6, 4, and 2 mm. These data were extrapolated to estimate the amount of HOAs in each eye with a 1.6 mm aperture to model the effect of a pinhole lens. Dynamic sciascopy (OPD-Scan III, Nidek) was used to predict corrected distance visual acuity (CDVA). Pearson correlation between LOAs and HOAs with CDVA was performed with a 95% confidence interval. In the single patient with keratoconus who underwent cataract surgery with IC-8 Apthera IOL implantation, the authors reported corneal and whole-eye HOAs with Scheimpflug tomography and ray tracing (iTrace, Tracey Technologies). Results This retrospective chart review included 56 keratoconus patients classified into mild (Amsler-Krumeich stage I), moderate (stage II), or severe disease (stages III and IV). There were no significant differences between age or gender across these 3 groups. As expected, when comparing to patients with mild disease, baseline Kmax values were higher in the moder- ate group and highest in the severe group. Significant correlations were observed between CDVA and total HOAs, LOAs, spheri- cal aberration, coma, and trefoil under natural photopic conditions. Data on HOAs obtained from 6, 4, and 2 mm apertures were used to extrapolate HOAs for the 1.6 mm effective aperture of the IC-8 Apthera lens at the corneal plane. After stratifying by disease severity, the authors found that at larger effective apertures, HOAs differed modestly between groups (severe eyes had higher HOAs compared to moderate eyes, which had higher HOAs compared to mild eyes). However, this relative difference between groups decreased with decreasing aperture size and appeared to nearly converge at the 1.6 mm aperture. The average theoretical root mean square (RMS) value for the extrapolated HOAs at 1.6 mm aperture size in the study was 0.12 μm. The authors described a case of a 66-year- old female who underwent cataract surgery and implantation of the IC-8 Apthera IOL. Preoper- atively, the measured corneal RMS HOAs were EyeWorld Journal Club review Masih Ahmed, MD Residency Program Director Cullen Eye Institute Baylor College of Medicine Houston, Texas Review of "Prediction of the small aperture intraocular lens on visual acuity in patients with keratoconus" K eratoconus can result in a highly aber- rated optical system and degraded vi- sual acuity. 1 Currently, available meth- ods to decrease the amount of higher order aberrations (HOAs) and lower order aberrations (LOAs), such as rigid contact lenses, scleral contact lenses, and intracorneal ring segments, act at the corneal plane. Howev- er, another well-known approach to decreasing optical aberrations is the pinhole effect, and pre- vious case studies have demonstrated improved visual acuity in eyes with irregular corneas with a small aperture piggyback IOL. 2,3 In this study, van den Berg et al. used Zernike analysis with different pupil sizes to model the effect of a 1.6 mm aperture on HOAs and predict visual acuity in patients with keratoconus. The authors also provided a case report of an individual with keratoconus who underwent cataract surgery with implantation of the Bausch + Lomb IC-8 Apthera small aperture IOL (1.36 mm) as proof- of-concept. A lens-based strategy to correct HOAs in patients with keratoconus would be beneficial for elderly patients with cataracts and those who are unable to easily use or tolerate contact lenses. Methods This study was a retrospective chart review of all patients with keratoconus seen at Storm Eye Institute, Medical University of South Carolina between July 2016 and October 2022. The IC-8 Apthera IOL received pre-market approval from the FDA on July 22, 2022 (CDRH, 2022). 4 Patients with keratoconus were categorized based on their Amsler-Krumeich classification, which is determined by the amount of induced myopia and/or astigmatism, average keratome- try values, and corneal pachymetry as measured with Scheimpflug tomography (Pentacam HR, Oculus). Eyes with nystagmus or confounding corneal pathology were excluded from the study. The Zernike analysis function on the Pentacam HR was used to calculate LOAs and

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