new advances in lens implants

[cellio]

According to this article, researchers are now testing a new kind of occular lens implant, one they describe as "multi-focus". This means that people who have cataract surgery and get these new lenses don't need glasses. (Until now, lens implants have a fixed focal distance, so you still need glasses sometimes.) Nifty! I'd love to know how they're doing that!

The article mentions in passing that while most people develop cataracts as they age, some are born with congenital cataracts, and that this latter group is the researcher's area of speciality. This got my attention and queued up my hopes.

Frustratingly, they then say nothing else about this aspect. And what I really want to know is: can these new implants work for people who had cataract surgery as children? If so, once they've spent a decade or so working out the bugs (beta tester? I don't think so!), this is exactly the sort of development that could make an enormous difference for me. (The barrier until now, as I understand it, has been that they can't put implants into eyes that have been without lenses as long as mine have.)

I'll have to pump my opthamologist for information about this. It's been a while since I've pestered her anyway.

Comments

[eub.livejournal.com]

No idea about the important aspect.

This article (PDF) (http://www.optometry.co.uk/articles/20010504/lavin.pdf) mentions two general kinds of multifocals, but talks mostly about Allergan's Array -- which may not be CNN's whizzy new one, since it's been FDA-approved since 1998 (http://drsamuelson.eyemdlink.com/EyeProcedure.asp?EyeProcedureID=18).

The lens uses five concentric zones with the first, third and fifth zones being far dominant and second and fourth zones being near dominant. The light distribution is arranged so that 50% of light is distant focussed, 13% is focussed for intermediate vision and 37% for near vision.

CNN article:
"We have put in 60 to 70 of these implants now and no one uses glasses for anything," Solomon said.

vs. the Lavin article:
While approximately 60% of patients with the Array will have good unaided reading vision, as well as good unaided distance vision, so that they are spectacle independent for most visual tasks, a proportion of these patients will still elect to use reading glasses for prolonged fine detailed visual tasks.

[cellio]

Oh, zones -- that makes perfect sense, now that you point it out. I was trying to imagine solutions involving physical manipulation of the lens.

The eye can be trained to use bifocals and trifocals, so it stands to reason that the brain can be trained to use these kinds of zones. (I don't really remember a time without bifocals, so I have no idea how long it takes people to adjust.)