Multifocal IOLs
Multifocal IOLs (MFIOLs) achieve both distance and intermediate/near vision by dividing light into 2 or more focal points (Fig 9-4). This is achieved by either refractive or diffractive optics, or a combination of the 2. Several multifocal lenses (including toric MFIOLs) have been FDA-approved for use in the United States (Fig 9-5). Models are available in various power adds.
The advantage of MFIOLs is reduced dependence on spectacles. Disadvantages include reduction in contrast sensitivity (which patients may perceive as dimmer vision), the presence of glare and halos (particularly in mesopic or scotopic conditions), and the presence of multiple images. Lower-add MFIOLs (ie, with their “near” focal point farther from the eye) may reduce some of these symptoms compared to higher-add MFIOLs. Patients with preoperative hyperopia may be less bothered by some of the visual aberrations associated with these lenses than patients with preoperative myopia. It is important for the cataract surgeon to counsel patients receiving MFIOLs about the intended postoperative visual outcome and limitations; a specialized consent process can be used.
MFIOLs are most suitable for use in patients with excellent ocular health; they can cause reduced quality of vision and unsatisfactory outcomes in patients with ocular pathology, such as amblyopia or diseases of the cornea, optic nerve (eg, glaucoma), or macula. MFIOLs work best when implanted bilaterally and when minimal postoperative astigmatism can be achieved. Options for patients unhappy with their uncorrected visual outcome due to residual postoperative refractive error include spectacle or contact lens correction, keratorefractive surgery, or IOL exchange, preferably performed before capsular fibrosis increases the difficulty of explantation.
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Braga-Mele R, Chang D, Dewey S, et al; ASCRS Cataract Clinical Committee. Multifocal intraocular lenses: relative indications and contraindications for implantation. J Cataract Refract Surg. 2014;40(2):313–322.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.