What Happens if My Prescription Isn’t Fully Corrected Following ICL Surgery?
- Posted
- Medically Reviewed by: Mr Mfazo Hove, Consultant Ophthalmic Surgeon
- Author: Mr Mfazo Hove
- Published: January 3, 2025
- Last Updated: October 13, 2026
TL;DR: Most patients having implantable collamer lens surgery, or ICL surgery, end up very close to their target, but a small remaining prescription is possible. If it affects your vision, it can be corrected with laser treatment on the cornea, the clear front surface of the eye, by repositioning a toric ICL, which corrects uneven focusing called astigmatism, or occasionally by exchanging the lens. The first step is always assessment: finding out why the prescription remains, because the cause decides both the correction and its timing.
Elective laser refinement waits for a stable prescription; a rotated or poorly positioned lens may need earlier action.
A residual prescription, meaning a remaining prescription after surgery, is a measurement to be explained, not a result to be accepted.
Implantable Collamer Lens Surgery: Prescription Accuracy
In eight-year follow-up of central-port ICLs, which have a small opening that allows fluid to flow through the lens, 93% of eyes were within one dioptre of the intended correction. A dioptre is a unit used to measure prescription strength.¹
The US regulatory trial of the latest spherical lenses for short-sightedness and toric lenses for astigmatism also reported high accuracy.² Even so, eyes are individual, and a small number of patients are left with a prescription worth correcting.
Why A Prescription Can Remain
- Lens power. Calculations are highly accurate but not perfect, particularly in very high prescriptions.
- Toric rotation. A toric ICL that turns away from its intended axis, the angle at which it needs to sit, corrects less astigmatism. Modern toric ICLs are generally stable,³ and when rotation does occur, the lens can be repositioned.
- Healing and the eye’s surface. Dryness in the early weeks can make the prescription appear different from how it will settle.
- Later change in the eye. Some eyes continue to drift over the years, which is different from a residual error after surgery. Our article on prescription progression after ICL explains the distinction.
Two further causes need a different response altogether.
If the vault, the gap between the ICL and your natural lens, is outside our target range, the issue is the lens’s position. Laser on the cornea would correct the prescription while leaving the underlying problem in place.
If the natural lens is beginning to cloud, a shift in prescription is an early sign of cataract. This is treated as a lens problem, not with laser.
Correction Options After ICL Surgery
The options for correcting a remaining prescription after ICL surgery depend on the cause.
Glasses For Specific Tasks
A small residual prescription may need nothing more than glasses for night driving.
Laser On The Cornea
Where the cornea is suitable, an excimer laser, which precisely reshapes the cornea, can correct the remaining prescription. Combining an ICL with corneal laser has been shown to be safe and effective, without affecting the ICL’s position,⁴ and has been used for decades in very high prescriptions.⁵
Repositioning A Toric ICL
If the lens has rotated, it can be turned back to its planned axis through a small incision.
ICL Exchange
Rarely, if the lens power or size is clearly wrong, exchange for a different ICL is the better answer.
Blue Fin Vision® Eye Clinic Approach
Blue Fin Vision® offers both corneal treatments, which act on the eye’s clear front surface, and intraocular treatments, which take place inside the eye. At our eye clinic, these treatments sit within the same consultant-led team, so the recommendation can follow what the assessment finds:
- Laser for a stable residual prescription on a suitable cornea.
- Repositioning for a rotated toric lens.
- Exchange for a lens of the wrong size or power.
- The Post-ICL Cataract Surgery Pathway for early lens change.
The Blue Fin Vision® Enhancement Policy
An enhancement is further treatment to fine-tune your vision. For eligible self-pay ICL patients, a clinically indicated enhancement within 24 months is provided at no cost to the patient under our written enhancement policy.
No cost means exactly that: no surgeon fee, no hospital fee, no diagnostic fee and no drops fee.
Enhancement is planned once your refraction, the measurement of your prescription, is stable and your eye is suitable. It is carried out by your original consultant.
Repositioning and exchange of the ICL sit within our own surgical pathway. Our in-house laser eye surgery service means laser enhancement does not require referral elsewhere.
For further information, read:
- Our ICL costs
- The Visian toric ICL guide
- Our ICL surgery checklist, which asks every provider to show their enhancement policy in writing
Book a consultant-led consultation with Blue Fin Vision® in London, Hertfordshire, or Essex to assess your remaining prescription after ICL surgery and discuss suitable correction options.
References
- Kamiya K, Shimizu K, Takahashi M, Ando W, Hayakawa H, Shoji N. Eight-year outcomes of implantation of posterior chamber phakic intraocular lens with a central port for moderate to high ametropia. Front Med (Lausanne). 2021;8:799078. doi:10.3389/fmed.2021.799078.
- Packer M. Evaluation of the EVO/EVO+ Sphere and Toric Visian ICL: six month results from the United States Food and Drug Administration clinical trial. Clin Ophthalmol. 2022;16:1541-53. doi:10.2147/OPTH.S369467.
- Hyun J, Lim DH, Eo DR, Hwang S, Chung ES, Chung TY. A comparison of visual outcome and rotational stability of two types of toric implantable collamer lenses (TICL): V4 versus V4c. PLoS One. 2017;12(8):e0183335. doi:10.1371/journal.pone.0183335.
- Moshirfar M, Thomson RJ, West WB Jr, McCabe SE, Sant TM, Shmunes MH, Ronquillo YC, Hoopes PC. Visual outcomes after sequential posterior chamber phakic IOL with corneal refractive surgery (bioptics) for the treatment of myopic astigmatism. Clin Ophthalmol. 2020;14:4337-46. doi:10.2147/OPTH.S285140.
- Zaldivar R, Davidorf JM, Oscherow S, Ricur G, Piezzi V. Combined posterior chamber phakic intraocular lens and laser in situ keratomileusis: bioptics for extreme myopia. J Refract Surg. 1999;15(3):299-308.
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. 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.
