What the ICL is
The implantable collamer lens (ICL) is a thin, soft, biocompatible lens — made of a collagen-based material — placed behind the iris and in front of the eye’s natural lens through a 3 mm incision. It works like a permanent internal contact lens: the cornea is untouched, which is why high powers and thin corneas — disqualifiers for laser — are often ICL candidates.
Who it suits
ICL is typically discussed for: high myopia or hyperopia beyond safe corneal-laser ranges; thin or irregular corneas; eyes with borderline topography where laser would be unwise; and patients whose lifestyle prefers a reversible, additive (rather than subtractive) approach. Suitability still requires a full work-up with one measurement unique to ICL: the space between the iris and the natural lens and the cornea’s inner curve, measured by specialised imaging, to size the lens correctly.
The procedure and recovery
Performed under anaesthetic drops (sometimes with light sedation), each eye separately. Through a small incision, the folded ICL is inserted and positioned; it unfolds gently and centres itself. The day is spent resting; most patients see a dramatic improvement by the next morning. Drops continue for weeks, and reviews check position, pressure and the lens’s relationship with the natural lens and corneal endothelium over the long term.
Risks and long-term care
ICL is an internal eye procedure, so its risk profile is different from surface laser: the important considerations include raised eye pressure, cataract formation in the natural lens over time (low with modern lenses but monitored), endothelial cell changes, and the rare need for repositioning or removal. Annual reviews continue for as long as the lens is in place. For correctly selected patients, published satisfaction is very high — and the cornea remains structurally untouched throughout.