I have recently started the fitting process for an RGP progressive lens with low add power. My first pair arrived last week, and the new pair with some fit adjustments should arrive sometime this week.
Quick background: My situation is a bit different from most in that I'm not presbyopic, but rather have strabismus (about 4-5 prism diopters). I've never worn prism in my glasses, as the deviation is small enough to hold the eye straight most of the time. When I get at all tired, though, my eyes cross, and therefore have to have reading glasses around to use a computer for more than a few hours with contacts (otherwise I wear work glasses). I give this background because my experience with multifocal lenses (both glasses and contacts) is a bit different, since I actually *can* accommodate through various powers of the lens and don't always know if I'm doing it ;p ).
That said, my brief experience last week was, overall, fascinating. It's hard to describe. Basically, the lens I am trying has about a 3mm diameter distance Rx at center, and then an aspheric design that adds up to +1.75 diopters radially outward (this actually makes a lot of sense from an optics perspective, but I digress). The result for me is that when I step outside in bright light I lose almost nothing (pupils dilated down within the distance-only region). Indoors I get multiple planes in focus, meaning I have to ignore other planes that are in focus and concentrate on the I you need, but it's much more seamless than I had expected. A bit weird, though.
Cons? Well, I am still a bit disappointed in the very close, which becomes blurry (especially when I'm tired). It seems like most of the time there is a mild blur everywhere, and so doing really detailed work (or trying to read very fine print, say the small text on the
contact lens bottle) is difficult when it gets close enough that you need to use just the reading Rx portion. And remember what I said about going outside in bright light? Well, it doesn't work so hot at night. My vision is good enough to drive at night, but I'd say just barely.
However, mid-range planes are all much clearer for me. Biggest problem right now? Unfortunately the starting values for the fit were slightly flat, and as a result the lenses move too much and I can't wear this pair without getting really bad spectacle blur in the evening and blinking blurs the universe for over 2 seconds. That's another downside to multifocal contacts -- the fit needs to be very stable if you want good vision (since they rely on the assumption that the pupil is centered).
I know this was long, but there you go... all the info I can give for now. I'll try to post an update with the next pair if anything changes with improved fit!
All the best,
Josh
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12-11-2008, 06:35 AM
Out of Curiosity
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