Collamer and the ICL's UV protection
What the lens is actually made of, why the eye ignores it, and what its UV filter does and does not protect.
Collamer is the biomaterial the ICL is made from: a soft, water-holding polymer blended with purified collagen. The collagen is why the eye treats it as familiar rather than foreign, so it sits quietly with minimal inflammation. Collamer also carries a built-in UV filter, but because the lens sits behind the iris, that protection covers only the back of the eye. It is not a replacement for sunglasses.
“UV protection” appears on nearly every ICL benefits list, almost always as a single bullet point with no explanation. It is a real property of the material and worth understanding properly, including its limits, which is the part those lists leave out.
What is Collamer?
Collamer is STAAR Surgical’s proprietary lens material: a hydrophilic (water-loving) polymer combined with purified collagen. The name is a contraction of collagen and polymer. Because it holds water, it stays soft and flexible inside the eye rather than behaving like a rigid plastic, which is what allows a lens several millimetres across to be folded into a tiny injector and inserted through a roughly 3 mm self-sealing opening.
Why the eye tolerates it: the fibronectin coat
This is the more interesting half of the material, and it is more specific than “biocompatible”. Within hours of implantation, the collagen in Collamer attracts a thin layer of fibronectin, a natural adhesive protein already circulating in the aqueous humour, the eye’s own fluid. That protein layer binds to the lens surface and effectively cloaks the implant.
The consequence is passive and self-sustaining: once the fibronectin coat has formed, it inhibits further protein and cell adhesion. Inflammatory cells do not settle on the surface, deposits do not accumulate, and the eye largely stops registering the lens as something to react to. This is why an ICL can sit in the eye for decades with minimal inflammatory response; the material does not fight the eye’s biology, it recruits it.
What an ICL looks like decades later
The most direct evidence that the material holds up comes from the operating room. When an ICL is removed during cataract surgery many years after it was implanted, surgeons routinely find it essentially unchanged: still clear, still soft and flexible, with no clouding, no yellowing, no surface deposits and no calcification. It comes out looking much as it went in.
That is not the norm for every implanted material, some intraocular lens materials are known to opacify or calcify over time. The fibronectin coat is a large part of why Collamer behaves differently. For a patient deciding on a permanent implant in their twenties or thirties, the decades-later observation is more reassuring than any laboratory specification.
Does the ICL block UV light?
Yes. Collamer incorporates a UV-absorbing filter, so an implanted ICL blocks ultraviolet light that would otherwise travel through to the back of the eye. It is a property of the material itself, not a surface coating, so there is nothing that can scratch off, wash away or degrade with time.
What that UV protection does not cover
Here is the caveat that benefit lists omit. The ICL sits behind the iris, near the back of the eye’s front chamber. Light only reaches it after passing through everything in front. So the UV filter protects structures behind the lens, and does nothing at all for the tissues in front of it.
| Tissue | Protected by the ICL? | Why it matters |
|---|---|---|
| Retina and back of the eye | Yes | Sits behind the implanted lens |
| Your natural crystalline lens | Partly | Directly behind the ICL, so it is shielded |
| Iris | No | Sits in front of the ICL |
| Cornea and conjunctiva | No | Where UV drives pterygium and surface damage |
| Eyelids and surrounding skin | No | A common site for skin cancers |
What UV filtering may actually do for the eye
Benefit lists say “UV protection” and stop. The honest version needs one piece of anatomy: in an eye that still has its natural crystalline lens, that lens already absorbs most ultraviolet light before it reaches the retina. So an ICL’s UV filter is not adding protection to a retina that had none; it is adding a filter in front of the crystalline lens, which changes where the plausible benefit sits.
- The crystalline lens, and cataract, the most plausible benefit. Cumulative ultraviolet exposure is an established risk factor for cortical cataract. An ICL sits directly in front of the crystalline lens and filters UV before it arrives, so there is a coherent mechanistic argument that it reduces the lifetime UV dose that lens receives. This is theoretical reasoning from a known mechanism, not a proven outcome: no study has shown that having an ICL lowers a person’s cataract risk, and it would take decades of follow-up to demonstrate.
- The retina and macula, added redundancy. UV and high-energy visible light exposure have been implicated in retinal and macular ageing, though the evidence is debated and far from settled. Because the crystalline lens already filters most UV, an ICL mainly provides a second layer rather than first-line protection here. Useful, but a smaller claim than it is usually made to sound.
- What it does not touch. Everything in front of the iris. See the table above. Those are the tissues where sun exposure causes the most common, most visible problems.
We state this as mechanism rather than outcome deliberately. UV filtering is a genuine property of the material with a sound rationale behind it; it has not been shown in clinical studies to change rates of cataract or macular disease, and you should be sceptical of any page that implies otherwise.
Can you feel it, or see it?
No to both. Essentially all of the eye’s touch sensation lives in the cornea, at the very front surface. The ICL rests well behind that, tucked behind the iris, where there are no nerve endings to register it. It is also completely transparent and hidden behind the coloured part of your eye, so nobody can tell you have one, including you, in a mirror.
Does it wear out?
No. Collamer is designed to remain stable inside the eye indefinitely, and unlike a contact lens it is never exposed to air, tears, handling or cleaning solutions, the things that degrade contact lenses and drive their replacement schedules. There is no maintenance, no cleaning and no expiry. See how long an ICL lasts for what that means in practice.
Collamer and lens sizing
One practical consequence of the material is worth noting. Because Collamer is soft and flexible, the lens conforms slightly to the space it is placed in rather than sitting rigidly. That is part of why a lens one size up or down behaves so differently in the same eye, and why choosing between the four sizes, and predicting the resulting vault, is the most consequential decision in the whole procedure.
Common questions about Collamer and UV
What is Collamer?
Collamer is the proprietary biomaterial the ICL is made from: a soft, flexible hydrophilic polymer blended with purified collagen. The collagen content is what gives it its name and is a large part of why the eye tolerates it so quietly.
Does the ICL block UV light?
Yes. Collamer incorporates a UV-absorbing filter, so the implanted lens blocks ultraviolet light that would otherwise pass through to the back of the eye. This is a genuine property of the material rather than a coating that can wear off.
Does an ICL mean I no longer need sunglasses?
No, and this is the most important caveat about ICL UV protection. The lens sits behind the iris, so it can only filter light heading to the back of the eye. It does nothing for your cornea, conjunctiva, eyelids or the skin around your eyes, which are exactly the tissues where sun exposure causes pterygium, surface damage and skin cancers. Keep wearing UV-blocking sunglasses.
Why does the eye accept a Collamer lens?
Because it is not treated as foreign. The collagen component makes the surface attract a natural protein layer from the eye’s own fluid, which effectively cloaks the implant. The result is minimal inflammatory response, which is why the lens can sit quietly inside the eye indefinitely.
Can you feel the ICL in your eye?
No. The lens sits behind the iris, well away from the corneal surface where all of the eye’s touch sensation is. There are no nerve endings where it rests; it is extremely soft and thin, and nobody can see it from the outside either.
Does Collamer degrade, cloud or calcify over time?
No. Collamer is designed to be stable inside the eye indefinitely and does not wear out the way a contact lens does. Unlike a contact lens it is never exposed to the air, to tears, to handling or to cleaning solutions, which is why it requires no maintenance at all. When ICLs are removed at cataract surgery many years later, they are typically found still clear, soft and free of deposits or calcification.
What is the fibronectin coating on an ICL?
Shortly after implantation, the collagen in Collamer attracts a thin layer of fibronectin, a natural adhesive protein already present in the eye’s fluid. That layer coats the lens and inhibits further protein and cell adhesion, effectively cloaking the implant so the eye stops treating it as foreign. It is the main reason the lens sits quietly for decades without deposits building up.
Does the ICL’s UV protection prevent cataracts?
There is a coherent mechanistic argument but no proof. Cumulative UV exposure is an established risk factor for cortical cataract, and the ICL sits directly in front of the natural crystalline lens and filters UV before it arrives, so in principle it reduces that lens’s lifetime UV dose. No study has shown that having an ICL lowers cataract risk, and demonstrating it would take decades of follow-up. Treat it as a plausible bonus, not a reason to choose the procedure.
Does the ICL protect the retina and macula from UV?
Partly, as a second layer. In an eye that still has its natural crystalline lens, that lens already absorbs most ultraviolet light before it reaches the retina, so the ICL adds redundancy rather than first-line protection. UV and high-energy visible light have been implicated in retinal and macular ageing, but that evidence is debated, and the ICL’s more plausible benefit is to the crystalline lens sitting right behind it.
Is the ICL made of plastic?
Not in the way a hard acrylic implant is. Collamer is a hydrophilic polymer, it holds water and stays soft and flexible inside the eye, combined with collagen. That softness is what lets the lens be folded into a tiny injector and inserted through a roughly 3 mm opening.
Next: the risks of ICL surgery, removal and longevity, or whether you are a candidate.
Educational content reviewed by ICL surgeons; not a substitute for an evaluation of your own eyes. Material specifications are set by the manufacturer and may be updated.