Short answer: For high short-sightedness, the evidence generally favours an implantable contact lens (ICL) over laser eye surgery. A Cochrane review of randomised trials found that, for prescriptions of about −6 to −20 D, lens implants were safer than excimer laser at one year: fewer eyes lost best-corrected vision, contrast sensitivity appeared better, and patients preferred them (Barsam & Allan, 2014). The American Academy of Ophthalmology notes that laser results are less predictable in high myopia (AAO, 2022). For low to moderate prescriptions, laser eye surgery remains the usual choice.
At Focus Vision we perform both ICL and laser eye surgery (LASIK, TransPRK and CLEAR), so the recommendation follows your eyes rather than the equipment we have. This guide explains why the balance shifts as prescriptions rise, the risks of each option, and who suits which.
What counts as a “high” prescription?
Short-sightedness (myopia) of about −6 D or more is usually called high. The Cochrane review looked at −6 to −20 D (Barsam & Allan, 2014), and an American Academy of Ophthalmology assessment found that from about −8 D, lens implants may give a better visual outcome than laser (Huang et al., 2009).
The prescription isn’t the only factor: corneal thickness and shape, dry eye and the depth of the front of your eye all matter. At Focus Vision, ICL is typically recommended for short-sightedness beyond −6.00 D, and suits myopia up to approximately −18.00 D, as well as long-sightedness and astigmatism (ICL page).
Why laser gets harder as the prescription rises
Laser eye surgery corrects short-sightedness by removing corneal tissue, and the higher the prescription, the more tissue it removes.
- A thinner cornea and ectasia. Ectasia is a rare but serious weakening and bulging of the cornea after laser surgery. Patients who developed it after LASIK were more short-sighted and had thinner corneas and less untouched corneal tissue left behind (Randleman et al., 2008). When LASIK alters 40% or more of the corneal thickness, the risk rises sharply (Santhiago et al., 2014). Modern screening keeps ectasia rare (AAO EyeWiki), but deeper treatments use up the safety margin.
- Less predictable results. Laser results are less predictable for high myopia than for low to moderate myopia (AAO, 2022), so the final prescription is more likely to be off target.
- Quality of vision. Correcting high myopia with LASIK may carry a greater risk of decreased quality of vision in some patients, such as glare and halos at night (AAO EyeWiki), because larger treatments change the cornea’s optical shape more.
Why an ICL suits high prescriptions
An ICL is a thin, flexible lens placed inside the eye, in front of your natural lens and behind the iris. It corrects your prescription without reshaping the cornea.
- No corneal tissue removed. The cornea keeps its full thickness and strength, so a high prescription doesn’t use up corneal tissue.
- Reversible. The lens can be removed or exchanged if needed (AAO; AAO EyeWiki).
- Less dry eye. Because corneal nerves aren’t cut, an ICL is associated with less dry eye than laser procedures (AAO).
- Strong evidence at high prescriptions. In the Cochrane review, lens implants led to significantly less loss of best spectacle-corrected vision at 12 months, appeared to give better contrast sensitivity, and scored higher on patient satisfaction (Barsam & Allan, 2014). In the three-year US trial of the current EVO ICL (629 eyes, average −7.62 D), 90.7% of eyes were within ±0.50 D of target (Parkhurst et al., 2025).
What the evidence says, in fairness to both
| Evidence | What it found |
|---|---|
| Cochrane review, −6 to −20 D (Barsam & Allan, 2014) | Lens implants safer than excimer laser at one year; better contrast; patients preferred them. Three small trials, older technology, one-year follow-up |
| AAO technology assessment (Huang et al., 2009) | From about −8 D, lens implants may give a better visual outcome than laser |
| Newer comparisons with SMILE (meta-analysis, 2022; Cao et al., 2021) | Vision similar; ICL ahead on safety index early, with the gap narrowing beyond six months; halos more common after ICL |
So the advantage of an ICL is clearest at the top of the range and in eyes with thinner corneas or dry eye. For moderately high prescriptions with healthy, thick corneas, modern laser, including flap-free CLEAR and TransPRK, can also be a good option.
The risks of an ICL
An ICL avoids corneal tissue removal, but it is surgery inside the eye, with its own risks:
- Cataract. Older ICL models were linked to cataract forming in front of the natural lens. With the current central-port design, rates of this cataract and of pressure problems are reduced (Packer, 2018); in the three-year EVO trial, 1 eye in 629 (0.16%) developed it (Parkhurst et al., 2025).
- Loss of corneal endothelial cells, the inner layer that keeps the cornea clear: an average fall of 6.7% at three years in the EVO trial (Parkhurst et al., 2025). This is monitored at your check-ups.
- Lens sizing (“vault”). If the lens sits too high or too low, it may need exchanging: 2 eyes in 629 (0.32%) in the EVO trial (Parkhurst et al., 2025).
- Halos at night, more often than after SMILE (Cao et al., 2021).
- Infection inside the eye, rare: about 1 in 6,000 implants in an international survey (Allan et al., 2009).
An ICL also needs regular check-ups for life, to monitor eye pressure, the lens position, your natural lens and the corneal cells. See Are implantable contact lenses safe? for the long-term evidence.
Laser has risks too: dry eye, glare and halos, under- or over-correction and, rarely, ectasia (AAO EyeWiki). See Types of laser eye surgery and dry eye, glare and halos after LASIK.
Who suits which?
| Your eyes | Usually suits |
|---|---|
| Low to moderate short-sightedness, healthy corneas of good thickness | Laser eye surgery: LASIK, TransPRK or CLEAR |
| High short-sightedness (beyond about −6 D) | Often an ICL, especially as the prescription rises; laser may still suit if the cornea is thick and healthy |
| Very high short-sightedness, thin corneas or significant dry eye | ICL |
| Front of the eye too shallow, or low corneal cell counts | Not an ICL: a minimum anterior chamber depth (3.00 mm in the US label) is needed (FDA, 2022) |
| Needing reading glasses as well (usually from the 50s) | Often refractive lens exchange |
Your surgeon recommends one option after measuring your eyes at your assessment.
Cost
All-inclusive prices per eye at Focus Vision (costs page):
| Procedure | From, per eye |
|---|---|
| ICL, including the anaesthetist | $7,000 |
| LASIK and Ray Tracing LASIK | $4,250 |
| CLEAR lenticule extraction | $4,250 |
| TransPRK | $3,500 |
Prices cover pre-operative assessments, the procedure and a year of follow-up appointments, with no surcharge for higher prescriptions; prescribed medications and eye drops are extra. After an ICL, laser fine-tuning, if needed, is free for two years under our enhancement policy. Medicare doesn’t cover ICL or laser surgery done to correct your prescription.
To find out which option suits your eyes, book a free optometrist assessment or call (07) 3239 5005.
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. doi:10.1002/14651858.CD007679.pub4. cochranelibrary.com
- American Academy of Ophthalmology. Refractive Surgery Preferred Practice Pattern. Ophthalmology. 2022. pubmed.ncbi.nlm.nih.gov/36543604
- Huang D, et al. Ophthalmology. 2009;116:2244-2258 (American Academy of Ophthalmology technology assessment of phakic intraocular lenses). pubmed.ncbi.nlm.nih.gov/19883852
- Randleman JB, Woodward M, Lynn MJ, Stulting RD. Risk assessment for ectasia after corneal refractive surgery. Ophthalmology. 2008;115(1):37-50. pubmed.ncbi.nlm.nih.gov/17624434
- Santhiago MR, et al. Association between the percent tissue altered and post-laser in situ keratomileusis ectasia in eyes with normal preoperative topography. Am J Ophthalmol. 2014;158(1):87-95. pubmed.ncbi.nlm.nih.gov/24727263
- American Academy of Ophthalmology. Ectasia After LASIK. EyeWiki. eyewiki.org/Ectasia_After_LASIK
- American Academy of Ophthalmology. LASIK for Myopia and Astigmatism: Safety and Efficacy. EyeWiki. eyewiki.aao.org
- American Academy of Ophthalmology. Implantable Collamer Lens (ICL). EyeSmart. aao.org/eye-health/treatments/implantable-collamer-lens-icl
- American Academy of Ophthalmology. Implantable Collamer Lens. EyeWiki. eyewiki.org/Implantable_Collamer_Lens
- Parkhurst G, Brinton JP, Faulkner A, et al. Clin Ophthalmol. 2025;19:3237-3248 (three-year US clinical trial of the EVO ICL). doi:10.2147/OPTH.S537739. pmc.ncbi.nlm.nih.gov/articles/PMC12420917
- Meta-analysis of SMILE versus the central-port ICL for myopia. J Refract Surg. 2022. pubmed.ncbi.nlm.nih.gov/35686713
- Cao K, et al. BMC Ophthalmol. 2021;21:450 (meta-analysis of ICL versus SMILE for myopia). doi:10.1186/s12886-021-02206-9. doi.org/10.1186/s12886-021-02206-9
- Packer M. The Implantable Collamer Lens with a central port: review of the literature. Clin Ophthalmol. 2018;12:2427-2438. pubmed.ncbi.nlm.nih.gov/30568421
- Allan BD, Argeles-Sabate I, Mamalis N. J Cataract Refract Surg. 2009 (international survey of endophthalmitis after ICL implantation). sciencedirect.com
- U.S. Food and Drug Administration. EVO/EVO+ Visian Implantable Collamer Lens – P030016/S035. 2022. fda.gov