Eyeworld

FALL 2024 | EYEWORLD | 15 normal population with a 4 mm pupil size. Even the most severe of keratoconus patients experi- ence a decrease in HOA down to 0.20 μm at a 1.6 mm pupil. In their discussion, the authors further solidify their case by citing a study involving the small aperture piggyback IOL use and its impact on quality of vision. 3 This study has multiple strengths, including sound methodology and being highly reproduc- ible. The authors clearly provided the reasoning for the variables included, how they carried out their analysis, and the data that resulted. Their own discussion was well thought out, and the logical conclusions from the data were easy to follow. The authors mentioned a caveat that reduc- ing total RMS HOAs with a 1.6 mm aperture does not guarantee high contrast vision due to residual HOA over the entrance pupil. One must consider the area outside the annular mask of the IOL as a potential for further degradation. The outer diameter of the opaque annular mask 0.72 μm and, using the same methods as with the patients above, they estimated 0.05 μm with a 1.6-mm aperture at the corneal plane. They reported an improvement in UDVA from 20/150 to 20/30 and measured final total RMS HOAs of 0.039 μm. Discussion In their retrospective study of 56 eyes with ker- atoconus, van den Berg et al. conducted Zernike analysis to obtain the corneal aberrations of three different simulated pupil diameters. They discussed how although higher order aberra- tions are accountable for a significant portion of the poor vision in keratoconus, lower order aberrations play a substantial role as well. The data show a significant positive correla- tion between HOA and logMAR visual acuity in keratoconus patients under natural pupil photopic conditions. More impressively, the results provided evidence that the extrapolated 1.6 mm pupil size reduces HOA in keratoconus patients to a level consistent with that of the continued on page 16 The Cullen Eye Institute class of 2026, from left: Daniel Rodriguez, MD, PhD, Sanchay Gupta, MD, MBA, Uma Balakrishnan, MD, Chelsea Livingston, MD, Ryan Wallace, MD, and Ali Mukhtar, MD Source: Cullen Eye Institute

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