I don't have cataracts, but do have presbyopia, and really hate my eyeglasses. Last year while I was at an aviation fly-in I attended a lecture about multi-focal lenses and other refractive surgery given by a pilot and ophthalmologist who specializes in these surgeries (and had a financial interest in enticing pilots to get the surgery). Several fellow pilots who had gotten multifocal lens replacements were there, too, and were uniformly pretty happy with their results.
The surgery is done one eye at a time with a fairly low risk of complications resulting in loss of vision, but it's fairly common to need a second surgery to fine-tune the refractive correction. Once the first, more severely affected eye has been stabilized, they do surgery on the second eye.
The current crop of multifocal implants work by having different focal lengths ground into the lenses at different diameters, allowing your eyes to focus by varying the diameter of your eye's iris, something that takes a little bit of time for your brain to learn, but it learns this new trick pretty quickly.
The ophthalmologist giving the talk liked to use different brands of implants in each eye, and did this because the two brands he used (
ReZoom and
ReStor) approached the focal lengths they use differently, allowing one eye to have better vision at distances the other lens was not quite so good at. This approach, the doctor reasoned, allows for better vision in a wider range of situations, and (once again) the brain adapts and learns how to use each eye and lens to its best advantage over time, and once learned, the user isn't even aware the brain is making decisions about which eye works best when.
The pilots who have had this surgery -- not all of them had cataracts beforehand -- were very impressed with their results, some claiming their eyesight was never this good when they were young, even. Those with cataracts were also delighted that their color vision had come back with the new lenses, and the colors they see now were bright and clear again.
Based on their comments and some other research I've done, I'd get these implants in a flash if I had cataracts that were impairing my ability to see well, but I've also learned a few things that tend to make me want to wait on getting my focally challenged, but otherwise healthy eyes fixed.
The first is some concern that most of the current lenses may cause an elevated risk of macular degeneration. The concern is that our eye's natural lenses have a slight amber-yellow tinge to them that filters higher-energy ultraviolet and violet light down to manageable levels and improves the eye's focus by reducing the harder-to-focus high-violet light. In other words, they work something like "amber vision" sun and driving glasses. The lenses I mentioned here don't have this yellow-amber tinge, and allow more UV and high-violet light to hit the retina, and that may accelerate macular degeneration. Some of the newer lenses that are working their way through the R&D and approval processes have yellow-amber tinting to address this concern.
Next in my list of reservations is that a new lens that focuses more like a natural lens has just come out. The new lens has the tinting I just mentioned, but operates differently from the multi-focal implants in that it is "hinged" and flexes as the muscles around the edge of the lens move, somewhat duplicating the function of a young eye's lens. I don't know if this truly works well or is just so much marketing hype, but am happily willing to wait until enough people have gotten this type of implant to develop some health data points on the procedure.
And that's what I know . . . hope it helps.