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Multifocal Contact Lenses
09-10-2013, 00:05 (This post was last modified: 09-10-2013 00:09 by Arcticdude.)
Post: #4
RE: Multifocal Contact Lenses
All current mainstream soft multifocal contacts are a simultaneous design. You have both a distant image and a near relatively clear image presented to the retina, and thus the brain, at the same time. Your brain then decides which to "see". In a monofocal system, you also have the presentation of both images (a distant one and a near one), yet one is out of focus and thus easy to ignore. Think about being 30 years younger and looking out a window at a distant tree. The tree is in focus, so that's what your brain "sees". The window is still there, just way out of focus; so it's easy for your brain to ignore that image. Vice versa, the window is now clear and the tree is out of focus. It (the tree) hasn't disappeared, only gotten out of focus.

All the current mainstream soft multifocal contacts present both these images to your brain. Thus, it has to learn to now ignore a relatively clear image and "see" the other. That can take some time. One eye alone will be quite blurry! So DO NOT CLOSE ONE EYE AND COMPARE!!! That only reinforces to your brain that things are blurry!

Most of my multifocal patients can do rather well, but it takes some time. The first thing that should have been done was determining which eye is dominant. That eye should usually (but not always and never should have worse) have slightly better distance vision than the nondominant eye. Males are almost exclusively eye dominant as they are hand dominant. Meaning right handed, right eyed and left handed, left eyed. It's not 100%, but close. Women on the other hand are about 60% cross dominant. Right handed, left eyed and left handed and right eyed. The other 40% are right, right and left, left. Interestingly enough, this seems to onset at puberty.

As a side note, if your female significant other does shoot very well, have her swap hands. Your right handed can't hit the broadside of a barn may split pennies left handed (and left eyed)!

Anyway, back to the contacts. I find several things to keep in mind. First, your brain needs time to adjust, so don't sweat your vision with your first pair of lenses! You've got to teach your brain how to see again! Second, you're really trying for functional vision. You should be able to do 85-90% of what you normally do without readers or distance overcorrection. Third, ignore any numbers on the contacts and how they relate to what you had previously (unless those were also multifocals). The numbers can often be significantly different. Fourth, people with currently pretty good distance vision without correction probably won't like the multifocals! Don't waste your time or your do tkr's time unless you REALLY hate using readers. In a couple years, your distance will have degraded enough to get things to work. Just wait until then. Fifth, you can use readers or a distance over correcting pair of glasses whenever you need to over top of your multifocal contacts. It won't hurt it. Sixth, few people get truly 20/20 distance (or better) and truly 20/20 at near. And those that do probably won't have it next year. Your eyes are changing by the minute and sometimes you can "have it all" and sometimes you can't. Some years you'll see better than others. Seventh, there are no mainstream multifocals for patients with moderate to large amounts of astigmatism. Your only contact lens options are distance only with readers for near or monovision (one eye distance and one eye near- but see next point). Eighth, most multifocals only really give you 2 working distances. We currently really work at 3 distances- long distance, computer distance and reading distance. It's VERY rare to get all three really clear with either multifocal contacts or monovision. With only 2 eyes and 2 focus points, it just doesn't happen. You have to decide which distances are the most important and work on those. I have a patient that spends 10-12 hours a day doing paperwork and spreadsheets on the computer. They have excellent reading and computer vision with their multifocal contacts. They have a pair of glasses they out on to drive. Fortunately, we've been able to keep the same pair of glasses for 2 years now, but that may change this year.

There is not currently a multifocal lasik, only monovision. There ARE multifocal implants for cataract implants. We ALL will get cataracts, unless we die young. The is at least one focusing implant out there, which has the potential, with a little luck and good surgical skills, to get us seeing very well at distance and very well at near without any glasses! Time will get that better. Something to look forward to as we get older!!

That covers the absolute basics. Ask any questions you have, please.

I also forgot to add that some years some multifocal patients will see much better with monovision the the multifocals and vice versa. Keep an open mind, because its all about being functional without the need for readers and glasses most of the time. Whatever works at that point in time is what you get prescribed by me.

John Mace
06 450LXi bigger bird
living in the wild hinterlands of the north
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Messages In This Thread
RE: Multifocal Contact Lenses - Arcticdude - 09-10-2013 00:05
RE: Multifocal Contact Lenses - RetDA - 09-10-2013, 09:52
RE: Multifocal Contact Lenses - RetDA - 09-10-2013, 10:39



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