ICL surgery is a vision-correction procedure in which an Implantable Collamer Lens is placed inside the eye to correct myopia, with toric versions also available for certain levels of astigmatism. Unlike laser vision correction, the procedure does not correct the prescription by removing corneal tissue.
Instead, the ICL is positioned inside the eye while your natural crystalline lens remains in place. If you are considering this procedure, you can learn more about ICL as a vision-correction option on our ICL treatment page.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Where Is the ICL Placed?
The ICL is a type of phakic intraocular lens. It is designed to sit in the posterior chamber of the eye, behind the iris and in front of the natural crystalline lens.
Once positioned correctly, the lens changes how light enters the eye so that it focuses more accurately on the retina. The natural lens is not removed during ICL surgery.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
This is one of the main differences between ICL implantation and procedures such as cataract surgery or refractive lens exchange.
What Happens Before ICL Surgery?
The surgical process begins well before the day of implantation. A detailed eye examination is performed to determine whether the procedure is appropriate and to select the correct lens.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Depending on your individual circumstances, the evaluation may include:
- Detailed measurement of your glasses prescription
- Confirmation that the prescription is stable
- Measurement of the anterior chamber depth
- Assessment of the size and anatomy of the eye
- Corneal measurements
- Corneal endothelial cell count
- Measurement of eye pressure
- Assessment of the anterior chamber angle
- Examination of the retina and other internal eye structures
Does the ICL Need to Be Sized for Each Eye?
Yes. ICL selection is individualized. The surgeon uses your eye measurements and refractive prescription to select the appropriate lens.
The goal is for the implant to sit securely and maintain the intended position without causing unwanted contact with surrounding structures.
For a Toric ICL, which is used to correct certain levels of astigmatism along with myopia, the surgeon also needs to account for the required axis orientation of the lens.
Is an Iridotomy Needed Before ICL Surgery?
This depends on the type of ICL being implanted. Older ICL models required peripheral iridotomies to create an additional pathway for fluid movement through the eye and reduce the risk of pupillary block.
Modern EVO/EVO+ ICL models have a central port that allows aqueous fluid to pass through the lens, so preoperative peripheral iridotomies are generally not required for these models. The exact preparation therefore depends on the specific lens being used and the applicable surgical protocol.
What Happens on the Day of ICL Surgery?
ICL surgery is usually performed as an outpatient procedure. The exact sequence can vary slightly according to the surgeon, lens model, and individual patient.
Step 1: The Eye Is Prepared
Eye drops are used to prepare the eye for surgery, and the pupil is generally dilated before the procedure. The area around the eye is cleaned carefully to reduce the risk of infection. The patient is positioned comfortably under the operating microscope.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Step 2: Anesthesia Is Given
ICL surgery is commonly performed using local anesthesia, often with numbing eye drops. Additional anesthesia or sedation may be used depending on the patient and surgical approach. You remain awake during the procedure, but the eye is numbed to minimize discomfort.
Step 3: A Small Corneal Incision Is Made
The surgeon creates a small incision in the clear peripheral portion of the cornea to provide access to the inside of the eye. Additional small openings may also be created to allow the surgeon to introduce instruments and manipulate the lens safely.
Step 4: The Eye Is Filled With a Viscoelastic Material
A clear ophthalmic viscosurgical device, commonly called a viscoelastic, is introduced into the anterior chamber. This helps maintain the appropriate space within the eye and protects delicate structures during lens insertion.
Step 5: The ICL Is Inserted
The folded ICL is loaded into a specialized injector and introduced through the small corneal incision. Because the lens is flexible, it can be inserted through a relatively small opening and then allowed to unfold inside the eye.
Step 6: The Lens Is Positioned Behind the Iris
Once inside the eye, the ICL is carefully positioned behind the iris and in front of the natural crystalline lens. The surgeon ensures that the lens is properly centered and that its supporting portions, called haptics, are appropriately positioned.
For a Toric ICL, particular attention is given to the lens axis because its cylindrical correction needs to remain appropriately aligned with the patient's astigmatism.
Step 7: The Viscoelastic Is Removed
After the ICL has been positioned correctly, the viscoelastic material used during the procedure is removed from the eye. This step is important because retained viscoelastic can temporarily increase eye pressure after surgery.
Step 8: The Eye Is Checked Before the Procedure Is Completed
The surgeon checks the position of the ICL, the condition of the eye, and the surgical incision before completing the procedure. The small incision used for modern ICL implantation generally does not require routine suturing.
How Long Does ICL Surgery Take?
The actual implantation procedure is relatively short. Patient information provided for EVO ICL describes the procedure as usually taking approximately 20 to 30 minutes or less.
However, the total time spent at the surgical facility can be longer because it includes preparation, anesthesia, postoperative assessment, and instructions for going home.
The procedure is generally performed one eye at a time, although the timing between treatment of the two eyes depends on the surgeon's approach and the patient's circumstances.
What Happens Immediately After ICL Surgery?
After the procedure, your eye is examined and you may be given eye drops or ointment. A protective shield may also be used depending on the surgeon's instructions.
Because your vision may be temporarily blurred and your eye may be sensitive immediately after surgery, you should arrange transportation rather than driving yourself home.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Postoperative medications and activity instructions will depend on your individual surgery and surgeon's recommendations.
What Is Checked After ICL Surgery?
Follow-up is an important part of ICL care. The surgeon checks the eye to make sure it is healing appropriately and that the lens remains correctly positioned.
Eye pressure is particularly important to monitor in the early postoperative period. An increase in pressure can occur after intraocular surgery and may require prompt treatment.
Follow-up examinations may also assess:
- ICL position and vault
- Eye pressure
- Inflammation
- Visual acuity
- Corneal clarity
- Overall eye health
What Is ICL Vault and Why Does It Matter?
Vault refers to the space between the back surface of the implanted ICL and the front surface of the natural crystalline lens.
The ICL is designed to sit at an appropriate distance from the natural lens. During follow-up, the surgeon may evaluate this relationship to make sure the implant is positioned appropriately.
Vault can vary between individuals because eye anatomy differs from person to person. This is one reason accurate preoperative measurements and appropriate lens sizing are important.
Can the ICL Be Removed After Surgery?
An ICL is designed for long-term implantation, but it can generally be removed or exchanged if medically necessary.
However, removal requires another intraocular procedure and should not be viewed as a simple or routine reversal of the original surgery.
The decision to remove or exchange an ICL depends on the reason, the condition of the eye, and the surgeon's assessment.
The Bottom Line
ICL surgery involves inserting a carefully selected Implantable Collamer Lens through a small corneal incision and positioning it behind the iris and in front of the natural lens. The natural crystalline lens remains in place.
The procedure involves several important steps: detailed preoperative measurements, eye preparation and anesthesia, creation of a small incision, insertion and positioning of the ICL, removal of the viscoelastic material, and postoperative monitoring.
Although the implantation itself is relatively quick, careful planning and follow-up are essential. Lens selection, positioning, eye pressure, and overall eye health all contribute to the safety and visual outcome of ICL surgery.
