Surgical Correction of Presbyopia

Lenticular, Corneal, and Scleral Approaches

Michael Greenwood, MD; Shamik Bafna, MD; Vance Thompson, MD

Disclosures

Int Ophthalmol Clin. 2016;56(3):149-166. 

In This Article

Multifocal IOLs

Multifocal IOLs have multiple focal points, which results in multiple images at different focal planes. The patient then perceives the image of interest while being able to suppress the others.[51–56] Multifocal IOLs can be divided into bifocal and trifocal IOLs. Bifocal IOLs provide 2 focal planes correcting for distance and near, whereas trifocal IOLs have 3 focal planes correcting for both distance and near, as well as intermediate vision. Both the bifocal and trifocal IOLs use the property of diffraction to provide near and distance vision. These IOLs have diffractive zones, or steps, across the surface of the lens, which allows for diffraction of the light, resulting in multiple focal planes. The larger the step height, the greater the diffraction of light. There are 2 categories of diffractive multifocal IOLs: apodized and nonapodized, which are explained in more detail below. When discussing multifocal IOLs, one must be familiar with their downsides. They can cause reduced contrast sensitivity and patients experience more glare and halos in comparison with monofocal IOLs.[57] If severe enough, a secondary intervention and IOL explantation might be required. A study by Mamalis et al[58] noted that the second most frequently explanted IOL was the multifocal hydrophobic acrylic IOL with the most common reason for explantation or secondary intervention being glare/optical aberrations (68%), followed by incorrect IOL power (21%). Accurate biometry, including intraoperative abberometry, for IOL calculation and correction of astigmatism is necessary for a good outcome after multifocal IOL implantation. The ability to correct any residual refractive error is very important to maximize outcomes. Residual corneal astigmatism reduced through-focus image quality and depth of focus with all IOLs evaluated in a study by Zheleznyak et al.[59]

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