Basic and mixed multifocal IOLs
Since standard monofocal intraocular lenses (IOLs) can only provide clear distance vision and require patients to wear reading glasses for close vision perception, presbyopia-correcting IOLs with multifocal designs are approved to offer clear vision at multiple distances. There are three brands of multifocal IOLs that are FDA-approved: AcrySof IQ ReSTOR, ReZoom and Tecnis.
Some brands of multifocal IOLs with different features
The original version of AcrySof IQ ReSTOR changes the way in which light is directed when it falls on the lens’ different zones and provides same vision correction at multiple distances, while the newer version provides better intermediate vision. ReZoom is actually an upgrading of the Array IOL and uses different zones within concentric rings for multiple focuses. Tecnis also uses a diffractive lens design and has gained both satisfying distance vision and near vision. In the future, toric designs may be applied to multifocal IOLs. At that time, an additional astigmatism correction will be available.
Use multifocal intraocular lenses in a mixed way
Even though their candidates only account for 5% to 10% of all cataract patients, some surgeons are still considering the idea of mixing and matching IOLs. For instance, they may use AcrySof IQ ReSTOR lens of a new version to enhance intermediate vision in one eye and the original version ReSTOR to bring sharper near vision to the other eye. This is exactly an application of monovision. From another perspective, such an application is a mixed use of basic types of multifocal intraocular lenses.
Monovision use of multifocal IOLs avoids coordination problems
If monovision is applied to single vision IOLs, the traditional problems such as uncoordinated eyes may occur, so that amblyopia or lazy eye may be caused. Since multifocal IOLs themselves can provide vision at multiple distances, monovision with multiple IOLs can maintain stereopsis and avoid amblyopia. Several combinations of different types of IOLs have been reported as a good way to get a high rate of independence from eyeglasses.
Who are good candidates?
There are also many people who are favored to receive multifocal IOLs. For patients’ eye conditions, those with good general health and active lifestyles, individuals having presbyopia and people with high level of myopia are more likely to get satisfied with visual results brought by multifocal lenses. People who are easy-going and realistic in their expectations as well as those who are willing to accept tradeoffs are also good candidates for multifocal IOLs.
Inappropriate candidates for multifocal IOLs
Multifocal IOLs are not suitable for extreme perfectionists, since their expectations can hardly be met. In fact, some people are not good candidates for multifocal IOLs. People requiring great night vision should not receive multifocal IOLs, because these IOLs may cause night glare and halos. Multifocal IOLs should also exclude people with high level of astigmatism, retinal diseases, perfect near vision or low to moderate degrees of myopia.
Some other points
After receiving an IOL implantation surgery, it is still necessary to visit the doctor periodically, in case of some implant-related changes. Another important factor that the patient should know is that multifocal IOLs require out-of-pocket fees, because most Medicare and insurance plans only cover standard or single-vision IOLs. Keeping a proper expectation is quite necessary because multifocal lenses implanted into the eyes sometimes require a period of adaption. Even if multifocal IOLs with monovision effect claim easier eye coordination, not all patients will be so lucky.