High myopia can make everyday vision heavily dependent on glasses or contact lenses, especially when the prescription is strong. For some people, ICL surgery may offer another way to correct significant nearsightedness without removing corneal tissue.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
However, having a high prescription does not automatically mean you are a candidate for an Implantable Collamer Lens (ICL). Candidacy depends on several factors, including your age, prescription stability, eye anatomy, corneal and retinal health, and the results of a detailed eye examination.
What Is Considered High Myopia?
High myopia is generally defined as a spherical equivalent refractive error of -6.00 diopters or more myopic. The exact prescription range considered suitable for ICL surgery depends on the specific lens and its approved indications.
People with high myopia may sometimes be considered for phakic intraocular lens surgery because the procedure corrects the refractive error using a lens placed inside the eye, rather than reshaping the cornea.
Who May Be a Candidate for ICL Surgery?
There is no single prescription or age that determines eligibility. Instead, an ophthalmologist evaluates several factors together.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
1. You Have Moderate to High Myopia
ICL is commonly considered when the level of myopia is significant and the prescription falls within the correction range of the selected lens.
For example, current U.S. FDA labeling for the EVO/EVO+ ICL includes correction of myopia from -3.0 D to -15.0 D and reduction of myopia greater than -15.0 D up to -20.0 D, subject to other eligibility requirements. Approved ranges can differ by lens model, country, and regulatory authorization.
This means that having a very high prescription does not automatically rule out ICL, but the exact prescription must be assessed against the appropriate lens specifications.
2. Your Prescription Has Been Stable
A stable prescription is an important part of ICL candidacy. Significant changes in your glasses or contact lens prescription may indicate that your refractive error is still changing.
For the FDA-approved EVO/EVO+ ICL indication, the refractive history is expected to have remained stable within 0.5 diopters for the year before implantation.
3. You Are Within the Appropriate Age Range
Age is considered because ICL surgery is generally performed in adults whose refractive prescription is stable and whose eyes are suitable for the implant.
Current U.S. FDA labeling for EVO/EVO+ ICL was expanded in 2025 to include patients from 21 through 60 years of age. Regulatory indications can vary between countries and lens models, so age alone does not establish candidacy.
4. Your Eye Has Enough Space for the Lens
Before ICL surgery, the ophthalmologist measures the internal dimensions of the eye to determine whether there is sufficient space for the implant.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
One important measurement is the anterior chamber depth (ACD), which describes the distance between the cornea and the front surface of the natural lens. The dimensions of the eye help determine whether the selected ICL can be positioned appropriately.
For the current FDA-approved EVO/EVO+ ICL indication, an anterior chamber depth of at least 3.00 mm, measured from the corneal endothelium to the anterior surface of the crystalline lens, is required.
5. Your Cornea Has Adequate Endothelial Cell Health
The cornea contains a delicate inner layer called the corneal endothelium. These cells help maintain the cornea's clarity by regulating its fluid balance.
Because an ICL is placed inside the eye, the health and density of these cells are assessed before surgery. An endothelial cell count that is below the required level may make ICL surgery unsuitable.
6. Your Eye Is Otherwise Healthy Enough for the Procedure
A high glasses prescription is only one part of the evaluation. The ophthalmologist also examines the overall health of the eye. This may include assessment of:
- Corneal shape and health
- Anterior chamber anatomy
- Eye pressure
- Natural lens health
- Retina and optic nerve
- Anterior chamber angle
- Corneal endothelial cell density
This assessment is particularly important in people with high myopia because a strong prescription can be associated with structural changes in the eye that need to be identified before elective refractive surgery.
Why High Myopia Does Not Automatically Mean You Need ICL
ICL is a refractive option, not a treatment that removes the underlying structural effects of high myopia. People with high myopia can have an increased risk of certain retinal and other eye problems. Therefore, an examination before refractive surgery should look beyond the prescription itself.
The goal is not simply to determine whether an ICL can correct the number on your glasses prescription. The evaluation also considers whether placing a lens inside the eye is appropriate for the health and anatomy of your particular eyes.
What Tests Are Used to Determine ICL Candidacy?
A comprehensive evaluation may include several measurements rather than a standard eye-power test alone.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
- Refraction: Determines the current glasses or contact lens prescription.
- Prescription history: Helps establish whether the refractive error has remained stable.
- Corneal evaluation: Assesses corneal shape and other characteristics.
- Anterior chamber measurements: Help determine whether there is adequate space for the ICL.
- Biometry: Provides important measurements of the eye.
- Endothelial cell count: Assesses the health and density of corneal endothelial cells.
- Eye pressure measurement: Helps identify conditions such as glaucoma or ocular hypertension.
- Retinal examination: Checks the back of the eye for abnormalities that can be associated with high myopia.
- Anterior chamber angle assessment: Determines whether the angle anatomy is appropriate for the implant.
The exact tests can vary according to the patient's eyes, the lens being considered, and the surgeon's evaluation protocol.
Can Someone With Very High Myopia Have ICL Surgery?
In some cases, yes. ICL is often considered for people with higher degrees of myopia, including prescriptions that may fall outside the practical range of some corneal laser procedures.
However, there is no single prescription at which ICL automatically becomes the right choice. Very high myopia still requires assessment of the eye's anatomy, retinal health, corneal endothelial cells, prescription stability, and the approved power range of the available lens.
For particularly high prescriptions, the surgeon may also discuss other refractive options or explain why refractive surgery may not be appropriate.
The Bottom Line
ICL surgery can be considered for some people with high myopia, but a strong prescription is only the starting point. Candidacy depends on factors such as age, stable refraction, the power range of the selected lens, internal eye measurements, corneal endothelial health, and the overall condition of the eyes.
If you are considering ICL for high myopia, a detailed examination can help determine whether an implantable lens is an appropriate option for your individual eyes rather than relying on prescription strength alone.
