Yes, LASIK (Laser-Assisted in Situ Keratomileusis) removes a small amount of corneal tissue to reshape the cornea and correct vision problems.
By doing so, it helps improve how light is focused on the retina, thus enhancing clarity in vision.
Understanding LASIK and Its Purpose
LASIK is a popular vision correction surgery that has transformed the lives of millions. It is primarily used to treat refractive errors, such as:
- Nearsightedness (myopia) – Difficulty seeing distant objects clearly.
- Farsightedness (hyperopia) – Trouble focusing on close objects.
- Astigmatism – Blurry or distorted vision caused by uneven corneal curvature.
The procedure is highly precise, utilising advanced laser technology to reshape the cornea, the clear tissue covering the eye. By altering the corneal shape, LASIK ensures that light entering the eye is focused correctly on the retina, reducing or eliminating the need for glasses or contact lenses.
How Does LASIK Remove Tissue?
LASIK employs a laser to remove microscopic layers of corneal tissue. Let’s break this process into clear steps to help you understand:
1. Creating the Corneal Flap
The surgery begins with the creation of a thin flap in the outer corneal layer. This step is necessary to access the underlying corneal tissue. The flap is typically created using:
- A microkeratome, a small handheld mechanical device that uses a blade.
- A femtosecond laser, which offers greater precision and a blade-free method.
The flap acts like a hinge, allowing the surgeon to fold it back gently and expose the stromal layer underneath. Importantly, this flap can later be replaced without stitches, as it naturally adheres back to the rest of the cornea.
2. Reshaping the Cornea
Once the flap is lifted, an excimer laser is used to remove pre-calculated, microscopic amounts of corneal tissue. The excimer laser emits ultraviolet light to vaporise tissue without heating or damaging surrounding areas.
The amount of tissue removed depends on the individual’s vision prescription. For instance:
- To treat nearsightedness (myopia), the cornea is flattened by removing tissue from the centre.
- For farsightedness (hyperopia), the edges are reshaped to make the cornea steeper.
- For astigmatism, the laser smooths the irregularities to ensure a more uniform corneal surface.
This tissue removal is what enables light to focus properly on the retina, eliminating vision errors.
3. Repositioning the Flap
After the corneal reshaping is complete, the surgeon repositions the flap back into its original position. No sutures are needed, as the flap naturally adheres due to the cornea’s properties. The healing process begins immediately post-surgery.
Why Does Tissue Removal Matter?
Corneal tissue removal is central to the success of LASIK because it directly impacts how the light enters and focuses within the eye. Here’s why that matters:
1. Precision in Vision Correction
LASIK removes tissue in micrometre (one-thousandth of a millimetre) increments. This fine precision allows surgeons to create a smoother corneal surface tailored to your exact vision needs.
2. Long-Lasting Results
By permanently reshaping the cornea, LASIK offers stable and long-lasting correction for refractive errors. Many patients report improved vision for decades following the procedure.
3. Minimally Invasive
The procedure requires removing only minimal tissue—just enough to achieve the desired visual correction. This retains the structural integrity of the cornea, ensuring durability and safety.
How Much Tissue Is Removed in LASIK?
The amount of tissue removed varies depending on the individual’s prescription. Here’s a breakdown:
- For mild corrections, around 10-15 micrometres of tissue may be removed. For context, the total corneal thickness averages around 500-550 micrometres.
- Higher prescriptions (stronger corrections) may require the removal of more tissue, but surgeons carefully assess your corneal thickness beforehand to ensure safety.
Only as much tissue as is necessary is removed, preserving the cornea’s strength while improving vision. This balance is achieved through preoperative screening and state-of-the-art technology.
Factors That Affect Tissue Removal
Several factors influence how much tissue is removed during LASIK:
1. Current Vision
Higher refractive errors—whether severe myopia or hyperopia—may require more tissue removal to achieve the ideal shape.
2. Corneal Thickness
The procedure’s success hinges on having a sufficiently thick cornea. Surgeons ensure enough tissue remains to maintain corneal stability and avoid complications.
3. Pupil Size
Larger pupils may demand a broader area of the cornea to be reshaped, meaning slightly more tissue may need to be removed.
4. Pre-Surgery Measurements
Comprehensive mapping using diagnostic tools such as corneal topography and pachymetry allows precise calculation of the amount of tissue to be removed.
Is Tissue Removal Safe?
Yes, LASIK is considered a highly safe procedure, particularly when performed by experienced surgeons using modern technology. The tissue removal process is meticulously planned to minimise risks and ensure favourable outcomes. However, eligibility plays a significant role in safety. Not everyone is a suitable candidate for LASIK.
Surgeons conduct thorough evaluations to assess your suitability, including:
- Corneal thickness
- Overall eye health
- Prescription stability
- General medical history
If LASIK isn’t suitable, alternative vision correction options such as PRK (Photorefractive Keratectomy) or implantable contact lenses may be recommended instead.
Does Removing Tissue Affect Corneal Strength?
While some strength is inevitably lost due to tissue removal, LASIK is designed to preserve the structural integrity of the cornea. Surgeons carefully calculate the depth of tissue removal to ensure that the cornea remains stable post-surgery.
For most patients, this slight change in corneal strength is imperceptible in daily life. Those with naturally thin corneas may be deemed ineligible for LASIK or advised to consider other procedures.
Benefits of Tissue Removal in LASIK
The carefully controlled removal of corneal tissue through LASIK offers several significant advantages:
- Clearer Vision: Improved focusing ability leads to sharp and stable vision.
- Quick Recovery: Most patients experience noticeable vision improvement within 24-48 hours.
- Long-Term Results: The cornea retains its reshaped form, delivering a durable correction.
- Customised Treatment: Each procedure is tailored to the individual, ensuring optimal outcomes.
Myths About Tissue Removal in LASIK
Despite LASIK’s popularity, misconceptions about tissue removal persist. Below, we debunk some common myths:
- Myth: Too much corneal tissue is removed.
Fact: Only tiny amounts (measured in micrometres) are removed, ensuring safety.
- Myth: LASIK weakens the eye excessively.
Fact: Corneal integrity remains strong with proper screening and modern tools.
- Myth: Removing tissue is risky for future surgeries.
Fact: Surgeons account for future considerations, such as cataract surgery, during LASIK planning.
Final Thoughts
Does LASIK remove tissue? Yes, but in a highly controlled and precise way. The procedure carefully reshapes the cornea by removing microscopic layers of tissue, enabling correct light focus and significantly improving vision. This minimally invasive method ensures safety, effectiveness, and long-lasting results, making it a trusted choice for millions worldwide.
If you’re considering LASIK, speak with a qualified eye surgeon to discuss your options and suitability. Understanding how tissue removal works can help you make an informed decision about enhancing your vision.
