COMMENTARY

Monovision vs Multifocal IOLs for Spectacle Independence After Cataract Surgery

William W. Culbertson, MD

Disclosures

March 03, 2014

In This Article

Viewpoint

Monovision with monofocal IOLs is the major competitor to multifocal IOLs for reducing spectacle dependence after bilateral cataract surgery. In the mind of the patient, the allure of being able to see well at distance and near with botheyes with multifocal IOLs trumps seeing well at either distance or near in 1 eye with monovision.

However, the potential problems of reduced contrast sensitivity and dysphotopsias associated with multifocal IOLs, possibly requiring IOL exchange, are difficult for a patient to appreciate before undergoing surgery. Moreover, surgeons cannot predict preoperatively which patients are going to experience "debilitating" problems postoperatively.

The most common cause of suboptimal satisfaction with multifocal IOLs is residual refractive error. Patients who are close to emmetropia postoperatively are more likely to be satisfied and tolerant of dysphotopsias than patients who have reduced uncorrected vision and dysphotopsias to boot. In the case of monofocal monovision, the uncorrected vision in the distance eye is the critical factor, because the distance eye is receiving no recruitment support from the fellow near eye. However, it appears that perfect distance correction is more important in multifocal correction than in monovision.

This study did not try to preoperatively estimate ocular dominance for selection of which eye was to be the distance eye vs the near eye in the monovision group. Moreover, the average achieved postoperative refractive error of -0.92 D in the monovision eye would not be an optimal target for intermediate vision (at 24 inches, for instance) and certainly would not be expected to provide good near vision (at 16 inches).

Patient satisfaction numbers may have been even better in the monovision patients if a greater degree of myopia (eg, -1.75 D) was targeted and achieved. With this, near correction patients would have had better visual acuity both at computer (intermediate) and reading (near) distance in the reading eye. However, the dominant/nondominant eye selection would have to be made preoperatively to avoid asthenopic symptoms associated with this higher degree of interocular blur. Furthermore, a preoperative monovision trial with contact lenses could have identified the patients who are naturally subpar candidates for monovision.

The endpoint of being 100% spectacle-free may not be as necessary as it seems to laymen. Patients with true monovision may be spectacle-free under almost all conditions, except perhaps for driving at night in a poorly illuminated environment, such as out in the country. On these occasions, it is easy enough for these patients to simply take their distance glasses out of the glove compartment and put them on to achieve perfect distance vision at night binocularly without the annoyance of the dysphotopsias that they might experience with multifocal IOLs.

In the United States, there is an economic incentive for surgeons to use multifocal IOLs in lieu of monovision with monofocal IOLs because the physician can legally make a surcharge to the patient for the use of a "premium" multifocal IOL. No such surcharge can be made for the use of monofocal lenses in monovision. The revenue accrued by the surgeon by implanting a multifocal IOL can be 2-3 times what is realized with monofocal IOL surgery alone. The preoperative work (eg, testing and analysis) and the intraoperative work are similar in both scenarios.

Surgeons can use comparative information provided by this study to advise their patients about whether it is worth spending the additional out-of-pocket money for multifocal IOLs, when they might expect similar satisfaction with a less expensive alternative.

Abstract

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