What are some advantages and limitations when it comes to monofocal vs trifocal IOLs?

07 Dec What are some advantages and limitations when it comes to monofocal vs trifocal IOLs?

In my ophthalmology training, patient complaints of “floaters and vitreous veils” were dismissed rather quickly as unimportant and likely to go away on their own. But it was not a very common complaint after cataract/IOL surgery then, probably because vision had to be really bad before surgery was done.

The actual choice here is between monofocal (single vision) IOLs and PRESBYOPIA-correcting IOLs, not just trifocals (or multifocal) ones.

There is a trade-off between getting uncorrected reading vision along with good distance vision and overall quality of vision. For example, the tri-and multifocal IOLs reduce contrast sensitivity some along with creating concentric rings around lights at night. The sharpest and highest quality distance vision is usually best achieved with an aspheric, monofocal IOL.

But there other ways to achieve both: the Crystalens is an accommodating IOL although the amount of accommodation is not always up to the expectations of many patients. There is also the segmented presbyopia-correcting IOL: the SLB3, rebranded the Clearview IOL. These are not nearly as likely to create halos or reduce contrast.

Overall, it is important to remember two things about IOLs:

1. Patients tend to judge success with ANY IOL by unconsciously comparing their post-op vision to the very best corrected vision they had when young.
2. There is NO IOL that can come close to the overall quality of vision afforded by the young, natural lens in the human eye.

This does not mean they are all inferior, but rather that achieving the best visual results post-cataract surgery is not simply a matter of having “the best” IOL “installed.”

Typically, these vitreous floaters and veils go away with time. This is partly from gravity slowly causing them to sink out of your line of sight and partly because your brain re-programs itself to filter them out of your awareness. If, after a suitable period of time (usually about 6 months or longer) they are still a significant impediment to your vision, they can be removed surgically with a pars plana vitrectomy (PPV). But this is another operation -and while rather quick and safe, is not exempt from possible complications no matter how rare.

_Written by J. Trevor Woodhams, M.D. – Chief of Surgery, Woodhams Eye Clinic