Lens replacement and implantable lenses (ICL): who they suit, and the checks before and after

An implantable lens (ICL) is placed in front of your natural lens, and its main approval trial enrolled short-sighted adults aged 21 to 45. Lens replacement removes the natural lens, as cataract surgery does, and is mostly used for people over 50. Both rely on detailed measurements beforehand and planned checks afterwards.

Implantable lenses (ICL)

An ICL is a thin lens placed behind the iris and in front of your own lens, which stays in the eye [1]. The United States approval trial for the current design enrolled people aged 21 to 45 with short-sightedness from -3.00 to -20.00 dioptres. In its 200-eye report on moderate short-sightedness, 91.5% of eyes were within half a dioptre of target at six months, and no eye lost more than one line of best-corrected vision [2].

A Cochrane review of three trials (228 eyes, -6 to -20 dioptres) compared lenses of this general type with laser surgery. Unaided vision at one year was similar. Fewer eyes lost best-corrected vision with the implanted lens, contrast sensitivity was better, and there was a low risk of early cataract. The trials ran for one year and used older technology [1].

The known trade-offs are:

• Cataract. With an earlier design, the five-year risk of a cataract that affected vision was 1.2% per eye, and older age and higher short-sightedness raised the risk. The current design has a central port intended to lower it, and a 2018 review found no vision-affecting cataracts reported up to five years [3].
• Cells lining the cornea. A meta-analysis of 18 studies found an average loss of 1.75% at 12 months and 3.84% at about 21 months, most of it early [4].
• Haloes and glare. A meta-analysis found haloes more often after ICL than after one type of laser surgery [5]. In a five-year study of 22 patients, 16 noticed glare and 7 found it mildly bothersome [6].

Lens replacement

Lens replacement (refractive lens exchange) uses the technique of cataract surgery on a lens that is still clear. It also removes the need for cataract surgery later [7]. Reviews describe it as an option for people over 50, and name long-sighted people who already need reading glasses as the group it suits most readily [8][9].

Points to weigh:

• Retinal detachment. A meta-analysis, as corrected by its authors in 2026, estimated this at about 1 in 50 after lens replacement and slightly less than 1 in 100 after cataract surgery, in studies with at least two years of follow-up (a median of four years). The authors say the figure may be an overestimate, because short-sighted eyes were probably over-represented in the studies [10]. The risk rises with eye length. In one clinic's records of 677 eyes of people under 61 who had cataract surgery or lens replacement, detachment occurred in 3.55% overall and in 10.2% of eyes 25 to 28.9 mm long [11]. Reviews advise a higher threshold for short-sighted people [8][9].
• Multifocal implants. In a Cochrane review of 20 trials in people having cataract surgery, multifocal lenses reduced the need for glasses and increased haloes and glare [12].
• Expectations. One review notes a higher risk of dissatisfaction in people who see well in the distance and only want to stop using reading glasses [9].

Dr James McKelvie's clinic, Eye Surgeons NZ, describes these procedures on its page about refractive surgery options, including lens replacement and ICL.

Checks before surgery

The optometrists at Rose Optometry use a Heidelberg ANTERION, a swept-source OCT instrument that images the whole front of the eye [13], for pre-operative measurements and corneal imaging.

• Space inside the eye. The ICL trial required a front chamber at least 3.00 mm deep and a minimum count of corneal lining cells [2]. How high an ICL sits above the natural lens (the "vault") is related to chamber depth, corneal width, lens thickness and age [14]. ANTERION readings of chamber depth and lens thickness were repeatable in 74 healthy eyes [15]. In 848 eyes, a sizing model based on ANTERION scans predicted vault to within a quarter of a millimetre in 81.7% [13]. The surgeon chooses the lens and its size.
• The retina. For very short-sighted eyes, a thorough examination of the back of the eye before lens surgery is advised [16].

Checks after surgery

After an ICL, our optometry team checks vision, eye pressure, the clarity of your natural lens, and the vault. Too much or too little vault has been linked with raised pressure, cataract and loss of corneal lining cells [3]. Vault can be measured on ANTERION scans [13]. In the approval trial it averaged about half a millimetre during the first six months [2].

After lens replacement, the checks match those after cataract surgery. The most frequent problems are clouding of the capsule behind the implant, a result that is off target, and swelling at the macula [8]. In the under-61 study, 92% of retinal detachments occurred within 3.6 years, so retinal checks continue well beyond the first few months [11].

The optometrists at Rose Optometry, 37 Lake Road, Frankton, Hamilton can take these measurements and discuss whether referral makes sense for you.

Choosing a surgeon: in Hamilton, lens replacement and ICL surgery are offered by Dr James McKelvie and his colleagues at Eye Surgeons NZ and by the surgeons at Laser Eye Centre. Hamilton Eye Clinic and Eye Institute also offer lens replacement. You are free to choose any of them, or another surgeon, and we will send your results to whoever you choose.

This article is general information and does not replace an eye examination.

Care at Rose Optometry is provided by our optometrist team: Jagrut Lallu, Jacqueline Rowe, Emilie Lawson, Jason Shen, Jessica Wood, Stella Wong and Anjali Hira.

References

1. Barsam, 2014, Cochrane Database Syst Rev. DOI PubMed 24937100
2. Packer, 2022, Clin Ophthalmol. DOI PubMed 36510599
3. Packer, 2018, Clin Ophthalmol. DOI PubMed 30568421
4. Kisiel, 2024, J Cataract Refract Surg. DOI PubMed 38194352
5. Cao, 2021, BMC Ophthalmol. DOI PubMed 34961514
6. Chen, 2025, BMC Ophthalmol. DOI PubMed 41068684
7. Alio, 2014, Surv Ophthalmol. DOI PubMed 25127929
8. Baur, 2024, Klin Monbl Augenheilkd. DOI PubMed 39146574
9. Maldonado, 2026, Arch Soc Esp Oftalmol (Engl Ed). DOI PubMed 42476410
10. Passaro, 2025, Br J Ophthalmol. DOI; correction published 1 March 2026, Br J Ophthalmol 110(3):e1 PubMed 40015940
11. Laube, 2017, PLoS One. DOI PubMed 28859157
12. de Silva, 2016, Cochrane Database Syst Rev. DOI PubMed 27943250
13. Zéboulon, 2026, J Cataract Refract Surg. DOI PubMed 40827890
14. Zhang, 2024, BMC Ophthalmol. DOI PubMed 38360631
15. Ruíz-Mesa, 2020, Expert Rev Med Devices. DOI PubMed 32425075
16. Srinivasan, 2016, Asia Pac J Ophthalmol (Phila). DOI PubMed 27898449

This article is general information, not personal medical advice. Most sources were checked against the full published papers in October 2026.