2020–2021 BCSC Basic and Clinical Science Course™
13 Refractive Surgery
Chapter 9: Accommodative and Nonaccommodative Treatment of Presbyopia
Nonaccommodative Treatment of Presbyopia
Custom or Multifocal Ablations
An excimer laser may be used to create a multifocal cornea. Prompted by the observation that, following excimer ablation, the uncorrected near vision of many patients improved more than expected (Fig 9-8), ophthalmologists began to investigate the potential for improving near vision without significantly compromising distance vision. To this end, the following ablation patterns have been employed:
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a small, central steep zone ablation, in which the central portion of the cornea is used for near vision and the midperiphery is used for distance vision
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an inferior near-zone ablation
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an inferiorly decentered hyperopic ablation
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a central distance ablation with an intermediate/near midperipheral ablation
Some of these patterns generate simultaneous near and distance images, whereas others rely on pupillary constriction (accommodative convergence) to concentrate light rays through the steeper central ablation.
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Although the excimer laser offers some potential advantages, the results of multifocal corneal ablations are still under investigation.
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Alarcón A, Anera RG, del Barco LJ, Jiménez JR. Designing multifocal corneal models to correct presbyopia by laser ablation. J Biomed Opt. 2012;17(1):018001. doi:10.1117/1. JBO.17.1.018001.
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Pallikaris IG, Panagopoulou SI. PresbyLASIK approach for the correction of presbyopia. Curr Opin Ophthalmol. 2015;26(4):265–272.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.