Eyeworld

16 | EYEWORLD | FALL 2024 ASCRS NEWS Contact Ahmed: Masih.Ahmed@bcm.edu References 1. Kosaki R, et al. Magnitude and orientation of Zernike terms in patients with keratoconus. Invest Ophthalmol Vis Sci. 2007;48:3062–3068. 2. Salmon TO, van de Pol C. Nor- mal-eye Zernike coefficients and root-mean-square wavefront errors. J Cataract Refract Surg. 2006;32:2064–2074. 3. Trindade CC, et al. New pinhole sulcus implant for the correction of irregular corneal astigmatism. J Cataract Refract Surg. 2017;43:1297–1306. 4. Center for Devices and Ra- diological Health. July 22, 2022. Premarket approval letter for the IC-8 ® Apthera TM Intraocular Lens (IOL) – P210005. United States Food and Drug Administration. www.accessdata.fda.gov/cdrh_ docs/pdf21/P210005A.pdf 5. Kanclerz P, et al. Applications of the pinhole effect in clinical visual science. J Cataract Refract Surg. 2024;50:84–94. 6. Manzanera S, et al. Adapta- tion to brightness perception in patients implanted with a small aperture. Am J Ophthalmol. 2019;197:36–44. 7. Dick HB, Gerste RD. Future intraocular lens technologies. Ophthalmology. 2021;128:e206– e213. The authors also provided a discussion in response to concerns about the pinhole IOL. In response to the concern that a pinhole may decrease brightness sensitivity, the authors cited corneal inlay data regarding enhanced bright- ness perception in the eye with the pinhole inlay. 6 The authors stated that the IOL has not been found to interfere with visualization of the retina. Anecdotal reports exist regarding the ability to conduct retinal surgery behind pinholes, and this is an area that will need to be further elucidated. 7 Overall, this study is a valuable addition to the growing body of work supporting the application of the pinhole effect to improve visual outcomes in patients with keratoconus. The option for a lens-based reduction of optical aberrations in patients with keratoconus ap- pears promising, particularly for those patients approaching the age for cataract extraction and others who may not be able to tolerate contact lenses. As this specific small aperture IOL was approved for use shortly before this study's con- clusion, we look forward to further real-world clinical data demonstrating the efficacy of this or other similar small aperture devices for pa- tients with keratoconus. is 3.23 mm. In conditions where a pupil is dilat- ed beyond this, aberrant light may enter outside the filtered area and affect vision quality. A limitation of the study is that it is an extrapolation based only on retrospective data. Although their findings were consistent with previous literature and their single case of IOL implantation, making extrapolated data from retrospective sources can still lead to significant bias compared to prospective data. Neverthe- less, their case report of the single patient lays the groundwork well for a prospective study involving the small aperture IOL in keratoco- nus patients. It is also important to note that the preoperative data in this patient showed the estimated corneal RMS HOA to be 0.05 μm. Postoperatively, total eye RMS HOA was evaluated, which was 0.039 μm. Total eye RMS HOA data takes internal HOA into account as opposed to just corneal HOA, but this does not seem to cause much deviance. The exclusion criteria only included cor- neal pathology and nystagmus. There was no mention of posterior segment or other pathol- ogy (such as a cataract) that would also affect vision. Two patients with low HOAs appeared to have poor vision, and addressing the causes of their decreased vision might have been helpful. continued from page 15 Prediction of the small aperture intraocular lens on visual acuity in patients with keratoconus van den Berg RM, et al. J Cataract Refract Surg. 2024;50:930–935. n Purpose: To investigate the impact of corneal higher order aberrations (HOAs) on predicted corrected distance visual acuity (CDVA) in patients with keratoconus at varying simulated pupil apertures. n Setting: Ophthalmology Clinics, Medical University of South Carolina, USA. n Design: Retrospective chart review study. n Methods: 56 eyes with keratoconus were examined using Scheimpflug tomography during routine examinations prior to medical intervention. The severity of keratoconus was graded using the Amsler-Krumeich classification. Zernike analysis was used to obtain corneal aberrations using simulated pupil diameters of 6, 4, and 2 mm. These data were extrapolated to obtain the total RMS HOAs for a 1.6-mm simulated pupil to evaluate the potential effect of a small aperture intraocular lens. Correlation analysis was used to study the impact and relative contributions of HOAs on CDVA. Convolution of HOAs from OPD-Scan III (Nidek) provided a clinical method to predict CDVA with different simulated pupil sizes in corneas with irregular astigmatism. n Results: There were statistically significant positive correlations between photopic CDVA and the magnitude of total and individual (coma, spherical aberration, and trefoil) HOAs in this cohort of keratoconus subjects. A keratoconus case with the small aperture IOL confirms the improvement in vision due to the pinhole effect. n Conclusion: The small aperture IOL is expected to markedly reduce aberrations in keratoconus patients up to Amsler-Krumeich class 4 severity to levels consistent with the levels seen in healthy patients. Convolution of corneal HO aberrations with the ETDRS chart provides a useful simulation of the impact of pinhole optics in aberrated eyes.

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