When the exam closes the laser door
A number of patients arrive expecting laser correction and leave with a different recommendation. Corneal thickness, corneal shape or the degree of correction required can each take laser off the table, and none of those are things you can assess yourself before the examination.
When that happens the conversation usually turns to an implantable collamer lens. It is worth understanding the reasoning ahead of time, because a recommendation that arrives unexpectedly is harder to weigh than one you have already thought about.
A different principle entirely
Laser procedures work by reshaping corneal tissue. That is why the amount of tissue you have, and the pattern of its curvature, set limits on what is possible.
An implantable lens does not reshape anything. A thin lens is placed inside the eye, in front of the natural lens, and the correction happens optically rather than structurally. The cornea is left as it is.
That difference is the whole reason the option exists. Where laser is limited by tissue, this route is not, because it is not removing any.
Who it tends to suit
Corneas too thin for the correction required. This is the most common reason patients are redirected. There is a minimum amount of tissue that must remain untouched after any laser procedure, and higher corrections remove more.
Higher degrees of short-sightedness, where the amount of reshaping needed would exceed what the cornea can support.
Certain corneal shape findings, where the topography suggests tissue that would respond poorly to removal.
Whether any of these describes you is determined by the examination, not by your prescription number. Two people with identical prescriptions can receive different recommendations.
What it involves
The procedure is performed on each eye and involves placing the lens through a small incision. It is done with the eye numbed rather than under general anaesthesia in the usual case.
Unlike laser correction, the lens is a physical object inside the eye, which brings two practical consequences. The first is that it can in principle be removed or exchanged, which laser tissue removal cannot. The second is that the follow-up schedule looks at how the eye is accommodating the lens as well as at the vision itself.
The recovery pattern, restrictions afterwards and follow-up intervals are set by your surgeon based on your eyes and the procedure performed. We are not going to publish figures here that would be guesswork for your case.
What to ask at your consultation
Whether an implantable lens is being recommended because laser is not possible, or because it is the better option among several. Those are different situations and worth distinguishing clearly.
What the exam found specifically. Thickness, topography and dark-adapted pupil measurements all feed the recommendation, and understanding which one drove it makes the decision yours rather than something handed to you.
What the follow-up schedule looks like, particularly if you are travelling from abroad and part of it would happen after you return.
What happens if the lens needs adjustment later, and where that would be done.
For patients travelling from North America
Send your prescription history and any corneal topography you already have before booking flights. That preliminary review will not replace the examination here, because thickness mapping and dark-adapted pupil size are not in those records. What it will do is indicate whether the trip is likely to be worthwhile and how many days to plan for, including whether the schedule needs to allow for a lens-based route rather than a laser one.
Our international coordination team will tell you what is missing from what you send.