Quick Reference: IOLs

A Look at IOLs, Both Up Close and at a Distance

What can current IOL technology offer presbyopic cataract patients?

René Luthe, senior associate editor

Patients seldom look forward to surgery, but presbyopic cataract patients have reason to be the exception. Current intraocular lens (IOL) technologies can address presbyopia and thus reduce — perhaps even eliminate — the need for the reading glasses so dreaded by patients "of a certain age." When counseling patients on their options, however, be sure to guard against unrealistic expectations. None of the lenses will restore to patients the vision they had when they were 20 years old — and all may require trade offs. Here's what you need to know about the latest and greatest in IOL technology.

Presbyopia-correcting IOLs (PC-IOLs) fall into one of two categories: accommodating or multifocal. Currently the only accommodating IOL on the U.S. market, the Crystalens (Bausch + Lomb) and its later iterations shift their position with the action of eye muscles in order to provide the ability to see at multiple distances.
The next-generation version of the Crystalens, the Crystalens HD (high definition) improved upon the original design by enabling better near vision while still providing excellent intermediate and distance vision. According to Bausch + Lomb, this lens is also less likely to cause glare or halos at night than the original lens.
The most recent generation of the Crystalens, the AO (aspheric optic), offers improved contrast sensitivity via an elongated shape. Even with these improvements, the Crystalens patient may require reading glasses. Mild to moderate hyperopes are usually the best candidates for the Crystalens.

Multifocal IOLs provide vision at multiple distances — near, intermediate and distance — via different zones in the lens. The brain learns to select the appropriate zone in order to see at each distance, in contrast to accommodating IOLs, which offer just one focusing zone. The multifocals available in the United States are Alcon's AcrySof IQ ReSTOR and AcrySof IQ Aspheric, and AMO's ReZoom and Tecnis.
According to many cataract surgeons, multifocal lenses offer the best near vision of any IOLs, and thus the best chance of eliminating reading glasses. However, there's a greater likelihood of glare and halos, rendering them not typically a good choice for patients who must drive at night.
While intermediate vision was often less-than-optimal in earlier multifocals, recent-generation multifocals promise better middle-distance focus. Multifocals tend to be a good match for patients who are very motivated to get rid of their reading glasses and who don't need to do much night driving.