{"id":18545,"date":"2026-09-25T11:36:09","date_gmt":"2026-09-25T11:36:09","guid":{"rendered":"https:\/\/www.eyecliniclondon.com\/blog\/?p=18545"},"modified":"2026-09-25T11:36:24","modified_gmt":"2026-09-25T11:36:24","slug":"icl-vs-smile","status":"publish","type":"post","link":"https:\/\/www.eyecliniclondon.com\/blog\/icl-vs-smile\/","title":{"rendered":"ICL vs SMILE: What\u2019s the Difference?"},"content":{"rendered":"

If you want to reduce your dependence on glasses or contact lenses, you may come across both ICL and SMILE when researching vision correction. Although both procedures aim to improve your unaided vision, they work in very different ways. ICL involves placing an additional lens inside your eye, while SMILE uses a laser to change the shape of your cornea.<\/p>\n

These differences can affect who may be suitable, the prescriptions that can be treated, your recovery and the risks involved. You do not usually need to decide between ICL and SMILE before your consultation. Your prescription, age, lifestyle and eye health can help your surgeon explain which options may be appropriate for you.<\/p>\n

What Are ICL and SMILE?<\/h2>\n

ICL stands for Implantable Collamer Lens and involves placing a lens inside your eye while your natural lens stays in place. SMILE uses a femtosecond laser to create and remove a small piece of corneal tissue called a lenticule, reshaping your cornea.<\/p>\n

The key difference is that ICL works inside your eye, while SMILE changes the shape of your cornea. Both aim to reduce your dependence on glasses or contact lenses, but your eye measurements and prescription help determine which may be suitable for you.<\/p>\n

How Does ICL Surgery Correct Your Vision?<\/h2>\n

ICL works somewhat like a contact lens, but it is placed inside your eye rather than on its surface, leaving your natural cornea largely unchanged. Your surgeon takes detailed measurements to check whether there is enough space for the lens and calculates the appropriate lens power for your prescription.<\/p>\n

During surgery, the folded ICL is inserted through a small corneal incision and positioned behind your iris and in front of your natural lens. Once in place, it becomes part of your eye\u2019s optical system and helps focus light more accurately, reducing your dependence on glasses or contact lenses.<\/p>\n

How Does SMILE Correct Your Vision?<\/h2>\n

SMILE corrects your vision by reshaping your cornea rather than placing a lens inside your eye. A femtosecond laser creates a precisely shaped lenticule within the corneal tissue, which your surgeon removes through a small opening. This changes the curvature of your cornea and how it focuses light.<\/p>\n

Unlike LASIK, SMILE does not require a large corneal flap, making it a flapless laser vision correction option. The corneal tissue removed during SMILE is not restored, although your eyes can still change naturally with age and your prescription may change over time.<\/p>\n

What Is the Biggest Difference Between ICL and SMILE?<\/h2>\n

The biggest difference is where each procedure corrects your vision. ICL adds an implanted lens inside your eye, while SMILE reshapes your cornea to change how it focuses light. This means SMILE requires suitable corneal thickness, shape and health, whereas ICL requires enough space and healthy structures inside your eye for the implant.<\/p>\n

ICL may sometimes be considered when your prescription or corneal characteristics make laser treatment less suitable. Neither option is automatically better, as your eye measurements, prescription and overall eye health help your surgeon determine which procedure may be appropriate for you.<\/p>\n

ICL vs SMILE at a Glance<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Factor<\/strong><\/td>\nICL<\/strong><\/td>\nSMILE<\/strong><\/td>\n<\/tr>\n<\/thead>\n
How vision is corrected<\/td>\nAdditional lens implanted inside the eye<\/td>\nCorneal tissue removed to reshape the cornea<\/td>\n<\/tr>\n
Natural lens<\/td>\nRemains in place<\/td>\nRemains in place<\/td>\n<\/tr>\n
Corneal reshaping<\/td>\nNo significant central corneal reshaping<\/td>\nYes<\/td>\n<\/tr>\n
Higher myopia<\/td>\nOften considered for stronger prescriptions<\/td>\nSuitability also depends on corneal thickness and treatment range<\/td>\n<\/tr>\n
Corneal thickness<\/td>\nDoes not determine the refractive correction in the same way as SMILE, although corneal health is still assessed<\/td>\nImportant for safe treatment planning<\/td>\n<\/tr>\n
Internal eye measurements<\/td>\nEssential<\/td>\nLess central than for ICL<\/td>\n<\/tr>\n
Dry-eye considerations<\/td>\nAvoids corneal tissue removal<\/td>\nTemporary ocular-surface changes can occur<\/td>\n<\/tr>\n
Can the correction be removed?<\/td>\nLens can usually be removed or exchanged surgically<\/td>\nRemoved corneal tissue cannot be restored<\/td>\n<\/tr>\n
Main additional risks<\/td>\nCataract, pressure changes, endothelial-cell loss and lens-related complications<\/td>\nDry-eye symptoms, residual prescription, visual disturbances and rare corneal complications<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Who May Be Suitable for ICL?<\/h2>\n

You may be considered for ICL if you want to reduce your dependence on glasses or contact lenses and your prescription and eye anatomy meet the treatment criteria. It can be particularly relevant for moderate to high short-sightedness, including prescriptions where laser treatment may require removing too much corneal tissue.<\/p>\n

Your eyes also need to be healthy, and your prescription should generally be stable before treatment. Your surgeon will assess your eye measurements, corneal health, eye pressure and internal structures to determine whether ICL is suitable for you. Age and the specific lens being considered can also affect your eligibility.<\/p>\n

Who May Be Suitable for SMILE?<\/h2>\n

\"\"<\/p>\n

You may be suitable for SMILE if you have short-sightedness, with or without astigmatism, and your cornea is healthy and suitable for laser vision correction. Your prescription also needs to fall within the treatment range of the laser technology being used.<\/p>\n

Your surgeon will assess your corneal thickness, shape and overall eye health before recommending treatment. A stable prescription is also usually required, and conditions affecting your cornea or other parts of your eye may mean that another vision correction option is more appropriate for you.<\/p>\n

Which Procedure Can Treat Higher Prescriptions?<\/h2>\n

ICL can often treat stronger levels of short-sightedness than corneal laser procedures such as SMILE. If you have a higher prescription, you may be offered ICL when the amount of corneal tissue needed for laser treatment is a concern. However, the approved treatment range varies between lens models, laser technology and countries.<\/p>\n

SMILE can also correct a broad range of short-sighted prescriptions, but your corneal thickness and shape can limit how much reshaping is suitable. Your surgeon will therefore consider your prescription, corneal measurements and overall eye health to decide which option may be appropriate for you.<\/p>\n

Evidence Note<\/strong><\/p>\n

Comparative research in adults with high myopia suggests that both ICL and SMILE can provide effective vision correction. A systematic review and meta-analysis of five observational studies involving 555 eyes found similar refractive predictability between the procedures. ICL showed higher efficacy and visual-acuity safety indices and a smaller increase in higher-order aberrations, but it was associated with a higher risk of halos. In refractive-surgery research, the \u201csafety index\u201d reflects changes in corrected visual acuity rather than the overall risk of complications.<\/p>\n

Because the evidence was based on observational studies, these findings should not be used to assume that one procedure is better for every person with high myopia.<\/p>\n

How Do Corneal Thickness and Shape Affect the Decision?<\/h2>\n

Corneal thickness and shape are particularly important when you are considering SMILE because the procedure removes a calculated amount of corneal tissue. Your surgeon will measure and map your cornea to check whether it is suitable for laser treatment and whether enough tissue can safely remain afterwards.<\/p>\n

If your cornea is thin, irregular or otherwise unsuitable, SMILE may not be recommended. ICL does not reshape the cornea, so it may be discussed when your corneal measurements limit laser options. However, your surgeon still needs to check the internal space and anatomy of your eye to ensure an ICL can be positioned safely.<\/p>\n

What If You Have Dry Eyes?<\/h2>\n

If you experience dry, irritated or uncomfortable eyes, tell your surgeon during your assessment. You may need to have dry-eye symptoms investigated and managed before vision correction, as SMILE can temporarily affect tear-film stability and corneal sensation.<\/p>\n

ICL does not reshape the central cornea, so it may be worth discussing if dry-eye concerns affect your suitability for laser treatment. However, ICL has its own risks, so your surgeon will assess your eye health and the cause of your symptoms before recommending a suitable option for you.<\/p>\n

Clinical Tip<\/strong><\/p>\n

Dry-eye symptoms should be assessed before either procedure. SMILE disrupts fewer corneal nerves than flap-based LASIK and generally has a relatively favourable ocular-surface profile, but temporary dry-eye symptoms can still occur after treatment.<\/p>\n

ICL may be worth discussing when corneal laser treatment is less suitable, but dry eye alone does not automatically make ICL the better option.<\/p>\n

What Happens on the Day of ICL or SMILE Surgery?<\/h2>\n

ICL and SMILE are both planned vision-correction procedures, but the treatment process is different. Your surgical team will explain what to expect and how to prepare before the procedure.<\/p>\n