Does Lasik Reduce Axial Length Of Eye

No, LASIK does not reduce the axial length of the eye. 

LASIK (Laser-Assisted in Situ Keratomileusis) is a procedure that reshapes the cornea to correct refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. The axial length of the eye, which refers to the distance from the anterior surface of the cornea to the retina along the eye’s optical axis, remains unchanged after LASIK.

To understand why this is the case, it’s essential to explore the purpose, methodology, and effects of LASIK, as well as the role of axial length in vision and eye health.

What is Axial Length and How Does it Affect Vision?

Axial length is a critical measurement in ophthalmology, as it plays a significant role in determining the refractive status of the eye. A normal axial length typically ranges from 22mm to 25mm in adults. Any deviation from this range can result in vision problems:

• Myopia (Nearsightedness): Usually occurs when the axial length is longer than average, causing light to focus in front of the retina instead of directly on it.
• Hyperopia (Farsightedness): Can result from a shorter-than-average axial length, where light focuses behind the retina.
• Axial-Related Pathologies: Highly elongated axial lengths (e.g., greater than 26mm) are associated with conditions like myopic maculopathy, retinal detachment, and glaucoma.

It’s important to note that axial length is a structural feature of the eye that develops during growth and typically stabilises by adulthood. While various treatment methods address refractive errors caused by abnormal axial length, the axial length itself is not directly altered through these interventions.

What Does LASIK Do?

LASIK aims to correct vision by reshaping the cornea—the eye’s transparent front surface—so that light entering the eye focuses directly on the retina, providing clearer vision. The procedure involves the following key steps:

1. Creation of a Corneal Flap: A thin flap is created on the outer corneal surface using a femtosecond laser or a microkeratome. This flap is lifted to expose the underlying corneal tissue.
2. Laser Reshaping: An excimer laser is used to remove microscopic amounts of corneal tissue, reshaping the cornea to correct the refractive error. For myopia, the cornea is flattened; for hyperopia, it’s steepened; and for astigmatism, irregularities are smoothed out.
3. Flap Repositioning: The corneal flap is repositioned, acting as a natural bandage while the eye heals.

While LASIK dramatically improves visual acuity for many patients, it achieves this by altering the corneal curvature rather than the axial length of the eye. The procedure’s success depends on changing the refractive power of the cornea, not on modifying the eye’s structural length.

Why Can’t LASIK Change Axial Length?

There are several reasons why LASIK does not and cannot alter the axial length of the eye:

1. LASIK Targets the Cornea, Not the Eye’s Internal Structures

Axial length is determined by the overall size and shape of the eye, including the length of the vitreous cavity and the position of the retina. LASIK, on the other hand, exclusively addresses the cornea at the front of the eye. The procedure’s laser treatment does not penetrate deep enough to affect the internal structures that determine axial length.

2. Impact on Vision Does Not Require Changes to Axial Length

LASIK achieves its intended outcome—clearer vision—by refining how light enters the eye and focuses on the retina. Correcting the refractive error through corneal reshaping eliminates the need to change the axial length, which is a far more complex and invasive alteration.

3. Axial Length is a Fixed Measurement in Adults

By adulthood, axial length typically reaches a stable size as the process of eye growth concludes. Altering axial length would require invasive interventions involving the sclera, the vitreous cavity, or even the retina. Such procedures could risk complications far greater than those associated with LASIK and are not advisable for cosmetic or refractive purposes.

Alternative Methods of Addressing Axial Length-Related Issues

While LASIK does not affect axial length, other treatments and technologies are relevant if an abnormal axial length leads to vision problems or ocular health concerns:

For Myopia and Hyperopia

• Orthokeratology (Ortho-K): Specialised contact lenses worn overnight temporarily reshape the cornea to address refractive errors. Like LASIK, this method does not change axial length.
• Phakic IOLs (Implantable Contact Lenses): These intraocular lenses are surgically implanted, providing high-quality vision correction without modifying axial length.
• Refractive Lens Exchange (RLE): Similar to cataract surgery, this procedure involves replacing the eye’s natural lens with an artificial one designed to address refractive errors.

For Associated Pathologies

• Myopia Control: For patients with significantly long axial lengths, treatments like low-dose atropine, multifocal contact lenses, or orthokeratology help slow the progression of myopia in children.
• Vitreoretinal Surgery: For complications like retinal detachment or myopic maculopathy, advanced surgical techniques address the resulting damage, though they do not change axial length.

Research on LASIK and Axial Length

Several studies have confirmed that LASIK does not reduce axial length. Instead, it alters the corneal curvature to provide refractive correction. For instance:

• A study published in the Journal of Cataract and Refractive Surgery (2010) measured axial lengths before and after LASIK procedures, finding no significant changes post-surgery. The study reinforced that LASIK’s effects were limited to the anterior corneal surface.
• Further investigations in clinical settings have ruled out any correlation between LASIK’s refractive outcomes and alterations to axial length, confirming its targeted impact on the cornea.

It’s worth mentioning that patients undergoing LASIK should be assessed for axial length beforehand, especially in cases of high myopia or where axial-related complications may pose surgical risks. Accurate preoperative measurements ensure better customisation of the LASIK procedure to achieve optimal results.

Key Takeaways

LASIK is a highly effective procedure for correcting refractive errors and improving visual clarity, but it does not affect the structural dimensions of the eye, including axial length. Understanding this limitation helps set realistic expectations for patients and guides eye care professionals in recommending suitable interventions.

For individuals with extreme axial lengths or related complications, other treatments may be more appropriate and should be discussed with a qualified ophthalmologist. Whether you’re an eye care professional or a curious patient, the key to superior outcomes lies in personalised care and informed decision-making.

If you’re considering LASIK or would like to explore alternative treatments crafted to suit your unique needs, consult with your eye care provider to discuss the best options for your vision and eye health.