My right eye points about 2.5 degrees higher than my left. I am going to have to have cataract surgery next year. Can the new lenses they are going to implant be made to correct the strabismus? Right now, there are corrective prisms in my glasses, which adds a fair amount to the cost and also means I cannot use drugstore reading glasses.
I am not an opthalmologist, but I have had cataract surgery and I do know a bit about the anatomy and physiology of the eye. On that basis, I would think that it is unlikely that cataract surgery, in itself, can correct your strabismus, which is, surely, a problem with the eye muscles (probably one of them is weak for some reason). I suppose a prismatic lens implant to correct it might be a theoretical possibility, but I doubt that the technology exists in practice. I think you are still going to need the special glasses. (And you are going to need glasses of some sort anyway. An implant will not give you correct focus at all distances.)
I’ve got an idea! Ask your doctor.
Seriously, though, I doubt it. Correcting strabismus (aka double vision) involve cutting or suturing the muscles that control the orbit of the eye.
I’m surprised that this wasn’t brought up when you were discussing the surgery.
I’m getting cataract surgery in less than 5 days. My new lens will correct what’s wrong with my existing lens, but strabismus isn’t a lens problem, so I can’t see how a new lens would correct it. Anyway . . . ask your ophthalmologist.
It just occurred to me that a new lens might correct it using the same principal that enables contact lenses to be bifocals . . . a tiny prism can be kept in place by blinking. Just a thought.
Well, I forgot to ask and it is impossible to communicate with him until the time comes for the cataracts–in the spring. I just wondered. The prisms are built in to the glasses, why not into the new lens?
Well, for one thing the prism in your glasses is held in place, so it redirects your gaze in the needed direction, by the frame. I am not 100% sure, but I think that when they put the new lens into your eye they do not anchor it to anything; they just pop it into the space where the old lens was. Maybe the tissues around it grip it and hold it still eventually, but during and immediately after the operation I do not think that there is anything to stop it rotating in place. This won’t matter with a symmetrical lens, but even a tiny bit of slippage is going to be a problem if it has a prism to direct your vision sideways (or up, or down,or whatever it is you need). If it rotates it could leave you worse off than before.
I also have my doubts as to whether the refractive index of the stuff they make the prosthetic lenses out of is sufficient to allow for directional correction of this sort in such a tiny lens.
If that’s the case, then how do they prevent rotation of an implanted lens that corrects astigmatism?
Can an implanted lens actually correct astigmatism? If so, I guess they have a way to anchor it after all.
Edit window missed due to poor server response:
Maybe the technology has improved since I had my cataracts done (10 years ago), but in my case, the results were not even perfect for focus, never mind fancy stuff like astigmatism or strabismus (not that I actually suffered from them before). Actually, my left eye is nearly in perfect focus for distance (although I am not sure that that was not more luck than judgment), but the right needs correction (by glasses) at any distance.
It’s theoretically possible – prism, (which corrects for strabismus) in vertical directions can be induced simply by displacing a spherical lens of a particular power so that you’re no longer using the optical center of the lens to refract rays directly from the object of regard, but rather a point peripheral to the optical center. So in theory all they’d have to do is displace a spherical intraocular lens inside the eye so that it’s not perfectly centered.
However, I’ve never heard of it done, and i have a lot of post-cataract patients I see, as part of post-op care and just in general for other reasons (I’m a fourth year optometry student, currently working at a VA hospital. (Just to add a disclaimer, that doesn’t mean it’s never done – I’ve just never encountered it.) My suspicion is that it’s fairly more complicated to correct for strabismus via an implanted lens as opposed to current extraocular muscle surgeries – today, with adjustable sutures, these strabismus surguries have become fairly accurate in a way that they were not in the past.
Keep in mind that even people who ask their cataract surgeon to make them free from refractive error via premium intraocular lenses still need glasses after surgery with some frequency; often corneal refractive surgery (i.e. LASIK, PRK etc) is needed to correct remaining refractive error, so it stands to reason that prismatic correction would be subject to the same margin of error in an implanted lens, but prism would be far more complex to induce via refractive surgery of the cornea, so that it couldn’t be “fixed” after cataract surgery in the same way cataract surgeons can “fix” refractive error after corneal surgery. So why mess around with an unknown and little-tried method, when a tried-and-true one (extraocular muscle surgery with adjustable sutures) is available?