- Medically Reviewed by: Mr Mfazo Hove, Consultant Ophthalmic Surgeon
- Author: Mr Mfazo Hove
- Published: October 10, 2024
- Last Updated: October 6, 2026
TL;DR: ICL surgery (Implantable Collamer Lens Surgery) has real downsides: it involves surgery inside the eye, with small risks of raised eye pressure, infection and, over the long term, cataract, clouding of the natural lens. The implanted lens must be sized correctly and monitored for as long as it remains in the eye, and treatment usually costs more than laser. None of this makes ICL a lesser option; it makes it an option that deserves honest planning.
ICL is an honest alternative, not a consolation prize.
Why ICL Is Not Second Best
Patients are sometimes told they are “not suitable for laser” as if ICL were the fallback.
The evidence says otherwise. For moderate to high short-sightedness, an independent Cochrane review of three trials, involving 228 eyes and older technologies, found phakic lens implantation safer than excimer laser surgery, and patients preferred it. Phakic lens implantation adds a lens without removing your natural lens; excimer laser surgery reshapes the cornea, the clear front surface of your eye. ¹
The ICL leaves the cornea untouched and can be removed. For many eyes it is simply the better operation, and you do not need to be unsuitable for laser to choose it.
England footballer Lucy Bronze chose an EVO ICL at around −3.00 dioptres, as her story explains. Dioptres are the units used to measure prescription strength.
Lucy Bronze MBE chose an EVO ICL even though she was suitable for laser eye surgery.
The Downsides of Implantable Collamer Lens Surgery
Raised Eye Pressure in the Early Weeks
In a series of 638 eyes, pressure rose to 22 mmHg or above in about 5% of eyes, most often as a response to steroid drops. The abbreviation mmHg means millimetres of mercury, the unit used to measure eye pressure.
In 31 of those 33 eyes it settled with medical treatment alone. ² This is why pressure is checked at your early reviews.
Infection
Infection inside the eye after ICL surgery is rare: a survey of users found a rate of about 1 in 6,000 implantations. ³ Rare is not never, which is why sterile technique and the warning signs matter.
Cataract Over the Long Term
The ICL sits close to your natural lens. Over years, some eyes develop lens opacity, meaning clouding of the lens, and the risk is higher when the ICL is implanted later in life.
In a 10-year study, patients who had surgery at 30 or younger had a lower long-term cataract risk. ⁴ Earlier lens designs without a central port, a small opening that allows the eye’s natural fluid to pass through, showed higher rates of cataract formation over a decade. ⁵
A cataract after ICL is treatable; our article on what happens if you get cataracts after ICL explains how.
The Cornea’s Inner Lining
The endothelial cells lining the inner surface of the cornea keep it clear. These cells do not regenerate, so they are counted before surgery and monitored afterwards. Central-port lenses have compared well with earlier designs. ⁶
Sizing And Vault
Vault is the gap between the ICL and your natural lens. If the implanted lens sits too close to or too far from the natural lens, it may need repositioning or exchange.
A review of ICL complications identified sizing as a central factor. ⁷ Exchange is uncommon, but you should know it is possible.
Night-Time Haloes
Some patients notice haloes, rings around lights, particularly in the early months. They usually become less noticeable over time. ⁷
Cost And Commitment
An ICL typically costs more than laser, and it asks you to keep attending monitoring appointments for life.
How Your Eye Clinic Manages ICL Risks
At Blue Fin Vision®, our eye clinic teams link each risk to an assessment before surgery, a way of detecting it afterwards and a defined response.
- Early pressure rise. Before surgery, the drainage angle, where fluid leaves the eye, and the optic nerve, which carries visual information to the brain, are assessed. The lens is sized to achieve the target vault. Your consultant contacts you the day after surgery, with an examination whenever clinically indicated. Pressure is measured from one week; pain, headache, nausea or blurred vision require urgent assessment. Treatment involves adjusting drops or, rarely, a laser opening or a further procedure.
- Infection. Before surgery, each eye undergoes sterile preparation as a separate procedure. Pain, increasing redness or falling vision must be reported urgently. The response is same-day assessment and treatment.
- Cataract. Before surgery, the lens is sized for adequate vault, and your age at surgery is considered. Your natural lens is examined at every monitoring visit. If a cataract develops, the pre-priced Post-ICL Cataract Surgery Pathway provides a treatment route.
- Endothelial cell loss. Before surgery, a baseline cell count is recorded and the anterior chamber depth, the space between the back of the cornea and the front of the natural lens, is measured. Specular microscopy, imaging that examines and counts endothelial cells, continues for life. Changes may lead to closer monitoring, ICL exchange or removal.
- Vault outside the target range. Before surgery, more than one measurement method is used to select the lens size. Vault is measured at early reviews and then for life. A result outside the target range may lead to closer review or exchange for a different lens size.
- Residual prescription or haloes. Before surgery, accurate measurements and toric alignment are used. Toric alignment means positioning a lens designed to correct astigmatism, blurred or distorted vision caused by uneven curvature of the cornea or natural lens, at the correct angle. Refraction, the test that measures your prescription, is performed at every visit. A residual prescription is prescription remaining after surgery. Options include glasses, laser treatment, repositioning or exchange.
Monitoring reduces the consequences of a complication. It cannot remove the risk of one, and you should hear that plainly.
For eligible self-pay patients, a clinically indicated enhancement, additional treatment to refine the remaining prescription, within 24 months is provided at no cost to the patient.
If a cataract develops, the Post-ICL Cataract Surgery Pathway provides both a clinical route and defined financial cover: no charge within two years of implantation, half price from two to ten years.
Read Before You Decide
Before your consultation, explore these resources:
- Read the full ICL risks page.
- Review our phakic intraocular lens information.
- Use our ICL surgery checklist to prepare your questions.
References
- Barsam A, Allan BDS. Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia. Cochrane Database Syst Rev. 2014;(6):CD007679.
- Senthil S, Choudhari NS, Vaddavalli PK, Murthy S, Reddy JC, Garudadri CS. Etiology and management of raised intraocular pressure following posterior chamber phakic implantable collamer lens implantation in myopic eyes. PLoS One. 2016;11(11):e0165469. doi:10.1371/journal.pone.0165469.
- Allan BD, Argeles-Sabate I, Mamalis N. Endophthalmitis rates after implantation of the intraocular Collamer lens: survey of users between 1998 and 2006. J Cataract Refract Surg. 2009;35(4):766-9.
- Choi JH, Lim DH, Nam SW, Yang CM, Chung ES, Chung TY. Ten-year clinical outcomes after implantation of a posterior chamber phakic intraocular lens for myopia. J Cataract Refract Surg. 2019;45(11):1555-61. doi:10.1016/j.jcrs.2019.06.015.
- Guber I, Mouvet V, Bergin C, Perritaz S, Othenin-Girard P, Majo F. Clinical outcomes and cataract formation rates in eyes 10 years after posterior phakic lens implantation for myopia. JAMA Ophthalmol. 2016;134(5):487-94.
- Goukon H, Kamiya K, Shimizu K, Igarashi A. Comparison of corneal endothelial cell density and morphology after posterior chamber phakic intraocular lens implantation with and without a central hole. Br J Ophthalmol. 2017;101(11):1461-5.
- Fernandes P, González-Méijome JM, Madrid-Costa D, Ferrer-Blasco T, Jorge J, Montés-Micó R. Implantable collamer posterior chamber intraocular lenses: a review of potential complications. J Refract Surg. 2011;27(10):765-76. doi:10.3928/1081597X-20110617-01.
ABOUT THE AUTHOR
Mr Mfazo Hove
MBChB MD FRCOphth CertLRS
Consultant Ophthalmic Surgeon | Founder and Medical Director, Blue Fin Vision®
Mr Mfazo Hove is a Consultant Ophthalmic Surgeon with more than two decades of experience across NHS and private practice and more than 57,000 ophthalmic procedures performed. He trained for six and a half years at Moorfields Eye Hospital and served for five years as an NHS consultant at the Western Eye Hospital, Imperial College Healthcare NHS Trust.
He specialises in cataract surgery, refractive lens replacement, laser vision correction and implantable Collamer lenses (ICL). He is the founder and Medical Director of Blue Fin Vision®, a private ophthalmology group providing consultant-delivered care across London, Hertfordshire and Essex. His cataract surgery outcomes are publicly reported through the National Ophthalmology Database.
A ZEISS Key Opinion Leader and international speaker, Mr Hove is a contributing author to The Ophthalmologist and Ophthalmology Times. His writing examines how clinical governance and the organisation of ophthalmic services shape patients’ experiences and outcomes, with a focus on transparent outcome reporting, surgical training and long-term accountability for patient care.
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Discuss your individual risks, treatment alternatives and aftercare before deciding whether ICL surgery is right for you.
