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CarbonRobot CarbonRobot
wrote...
Posts: 393
Rep: 8 0
A year ago
I have read that the human eye's lens is held in place with zonular fibers. But if the lens needs to be removed and replaced with an artificial lens do these same fibers attach to the new lens? Can the new lens be focused without them?
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Anonymous
wrote...
A year ago
The intraocular lens that is inserted sits in the capsule of the old lens. It does not accommodate, so most people still need glasses for reading. Some new multifocal lenses have attempted to address the problem with variable success. This video explains it nicely:

wrote...
Staff Member
A year ago
Not my own answer, but answers your question nonetheless

The intraocular lens (IOL) can be placed in three different places in the eye with almost 100% stability and permanence. The cataract is somewhat like a grape with a skin, a soft pulp, and a hard core. Modern cataract surgery opens the grape peel, breaks the hard pit into pieces, and sucks out the soft material, leaving an empty skin that we call the capsule. Most surgeons fold the IOL to fit inside the hole in the capsule and allow the lens to unfold and open, so that it is now larger than the hole through which it was placed into the empty grape skin or capsule. The lens should stay there forever. Alternatively, the lens can be placed in front of the capsule and braced against the capsule for support, what we call sulcus fixated. It too should stay in place forever. Rarely, we need to place an implant in front of the iris supported by the place where the iris ends and the white part of the eye (sclera) begins. This too should provide long-term stability. Ask your eye doctor to show you diagrams of these placement issues.

Hope it helps!
Source  https://www.sharecare.com/health/cataracts/intraocular-lens-implanted-cataract-surgery
- Master of Science in Biology
- Bachelor of Science
CarbonRobot Author
wrote...
A year ago
Not my own answer, but answers your question nonetheless

The intraocular lens (IOL) can be placed in three different places in the eye with almost 100% stability and permanence. The cataract is somewhat like a grape with a skin, a soft pulp, and a hard core. Modern cataract surgery opens the grape peel, breaks the hard pit into pieces, and sucks out the soft material, leaving an empty skin that we call the capsule. Most surgeons fold the IOL to fit inside the hole in the capsule and allow the lens to unfold and open, so that it is now larger than the hole through which it was placed into the empty grape skin or capsule. The lens should stay there forever. Alternatively, the lens can be placed in front of the capsule and braced against the capsule for support, what we call sulcus fixated. It too should stay in place forever. Rarely, we need to place an implant in front of the iris supported by the place where the iris ends and the white part of the eye (sclera) begins. This too should provide long-term stability. Ask your eye doctor to show you diagrams of these placement issues.

Hope it helps!

Thanks, but this doesn't show how an artificial lens could be made to focus like a natural lens can. I don't know how far we are from lens regeneration so this might be the only option for cataracts or lens thickening.
wrote...
Staff Member
A year ago
Quote
Thanks, but this doesn't show how an artificial lens could be made to focus like a natural lens can.

Implanted lens aren't designed to accommodate, as pointed out by the anonymous member. It is the best solution we have at the moment.

Read the part on Molecular mechanism and strategy promoting lens regeneration found in this article to get a sense of what we understand so far regarding lens regeneration in humans.
- Master of Science in Biology
- Bachelor of Science
CarbonRobot Author
wrote...
A year ago
Quote
Thanks, but this doesn't show how an artificial lens could be made to focus like a natural lens can.
Implanted lens aren't designed to accommodate, as pointed out by the anonymous member. It is the best solution we have at the moment. Read the part on Molecular mechanism and strategy promoting lens regeneration found in this article to get a sense of what we understand so far regarding lens regeneration in humans.

Think I've read that article before. Bothersome that it came out as recently as 2020 which likely means little progress has yet been made.

It's a shame the fake lens doesn't muscularly focus like the natural lens. We already have the cornea for passive broad stroke focusing.
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