ICL Phakic Lens Implantation

A phakic intraocular lens is a lens implanted in an eye that still has its own natural lens, which is what distinguishes it from cataract surgery. The ICL is placed in the posterior chamber, in the small space between the iris and the natural lens, where it is held gently in position by its haptics resting in the ciliary sulcus. It is manufactured individually for each eye from the measured prescription and the internal dimensions of that eye. Current designs include a central port that allows fluid to circulate through the lens, so a separate laser opening in the iris is no longer routinely required. Toric versions correct astigmatism and are aligned to a specific axis during surgery. Nothing about the cornea is altered, and the natural focusing lens is left untouched, so the eye's own anatomy is preserved.

ICL implantation is recommended for adults whose prescription has been stable for at least a year and who want to reduce their dependence on glasses or contact lenses. It is the preferred option over corneal laser surgery when the prescription is high, when the cornea is too thin to allow safe tissue removal, when corneal topography is irregular or shows early signs of thinning disease, and when significant dry eye would be made worse by a laser procedure. It also appeals to people who want a correction that can be reversed. The eye must have enough space in the anterior segment, a healthy corneal endothelium with an adequate cell count, normal intraocular pressure and no significant cataract. It is not usually recommended in the presence of glaucoma, uveitis, a shallow anterior chamber, a low endothelial cell count or an active corneal disease.

Planning is detailed, because the lens is custom-made. Measurements include the refraction, corneal topography and thickness, anterior chamber depth, the internal horizontal diameter of the eye measured by ultrasound biomicroscopy or anterior segment imaging, and an endothelial cell count. The lens size and power are ordered from these figures. On the day, anaesthetic drops are used, often with a mild sedative, and the eye is prepared and the pupil dilated. A small incision of about three millimetres is made at the edge of the cornea, viscoelastic gel protects the internal structures, and the folded lens is injected slowly into the anterior chamber. Using a fine instrument, the surgeon tucks each of the four footplates behind the iris so that the lens settles in the posterior chamber, and a toric lens is rotated to its planned axis. The gel is washed out, the incision seals itself without a stitch, and pressure is checked. Each eye takes about 15 to 30 minutes and the patient goes home the same day.

A full refractive assessment is required, including a dilated examination of the retina, since people with high short sight have a higher background risk of retinal problems and any weak area is treated with laser before the implant. Contact lenses are left out for a period before the measurements, typically several days for soft lenses and longer for rigid ones, so the cornea returns to its natural shape. The lens is then ordered and manufactured, which takes time and is the reason scheduling matters for international patients: measurements can sometimes be taken locally to an agreed protocol and sent ahead, but most centres prefer to measure the eye themselves, which means either a longer single trip or two visits. Blood-thinning medicines are usually continued. Eye drops are started shortly before surgery.

Vision is often usable within hours and clear by the following day, when the first check measures pressure and confirms the lens is correctly positioned. Mild grittiness, light sensitivity and haloes around lights at night are common in the first weeks and settle. Antibiotic and anti-inflammatory drops are used for about two to four weeks on a tapering schedule. Rubbing the eye, swimming, saunas and eye make-up are avoided for two to four weeks, and screen work and driving are resumed as soon as vision is comfortable, often within a few days. For treatment abroad, plan about 4 to 7 days: this covers the measurements and consent, the surgery on both eyes, the day-one check and the one-week review. Flying is generally comfortable once the one-week check is done. Long-term, an annual examination with pressure measurement and endothelial cell count is recommended, and this can be carried out by an ophthalmologist near home.

ICL implantation is a well-established procedure with high patient satisfaction, and the majority of eyes achieve the intended correction. The recognised risks relate to placing an implant inside the eye. Raised intraocular pressure can occur in the early period, usually from retained viscoelastic and treated with drops. If the lens vault, the gap between the implant and the natural lens, is too small, the natural lens can develop a cataract over time; if it is too large, the angle of the eye can be crowded and pressure can rise, and in either case the lens can be exchanged for a different size. Loss of endothelial cells occurs slowly and is monitored at annual checks. Uncommon risks include infection inside the eye, which is rare but serious, lens rotation in toric implants requiring realignment, glare and haloes at night, and retinal detachment, whose background risk is related to high short sight itself. The lens is designed to remain indefinitely, and it can be removed at any time, including when cataract surgery becomes appropriate later in life.