Myopia, commonly known as nearsightedness, is a vision condition where distant objects appear blurry, while close objects remain clear. This widespread refractive error can significantly impact daily activities. Laser eye surgery offers a modern and effective solution for correcting this common vision impairment. This surgical approach aims to reduce or eliminate the need for corrective lenses.
Understanding Myopia
Myopia occurs when the eye does not focus light correctly onto the retina, the light-sensitive tissue at the back of the eye. This typically happens because the eyeball is too long from front to back, or the cornea, the clear front surface of the eye, is too steeply curved. As a result, light focuses in front of the retina instead of directly on it, causing distant images to appear blurred.
Myopia is a common condition, affecting approximately 30% of the global population. This number is projected to increase, with estimates suggesting nearly 50% of the world’s population could be myopic by 2050. The condition often begins in childhood and can progress through adolescence.
Methods of Laser Vision Correction
Modern laser eye surgery offers several distinct methods to correct myopia, each with unique characteristics. The most commonly performed procedures include LASIK (Laser-Assisted In Situ Keratomileusis), PRK (Photorefractive Keratectomy), and SMILE (Small Incision Lenticule Extraction). These techniques reshape the cornea to improve vision, differing in how they access the tissue.
LASIK is a widely recognized procedure where a thin, hinged flap is created on the cornea’s surface using a laser or a microkeratome. This flap is then gently lifted to expose the underlying corneal tissue. Once reshaped, the flap is repositioned, allowing for rapid healing.
PRK, an older but still effective method, involves removing the outermost layer of the cornea, known as the epithelium. Unlike LASIK, no flap is created; the laser works directly on the corneal surface. The epithelium then regenerates naturally over a few days to weeks.
SMILE is a minimally invasive technique that differs from both LASIK and PRK by not creating a large flap or removing the surface layer. Instead, a femtosecond laser creates a small, lens-shaped piece of tissue, called a lenticule, inside the cornea. This lenticule is then removed through a tiny incision, typically less than 4 millimeters, reshaping the cornea.
How Laser Surgery Works
The fundamental principle behind laser eye surgery for myopia involves precisely reshaping the cornea to alter how light enters the eye. An excimer laser is the primary tool used in most of these procedures. This specialized laser emits a cool ultraviolet beam that removes microscopic amounts of corneal tissue.
In the case of myopia, the excimer laser flattens the central part of the cornea. This change in curvature allows incoming light rays to bend correctly and focus directly onto the retina, rather than in front of it. The precise amount of tissue removed is determined by detailed measurements of the individual’s eye, ensuring a customized correction.
Altering the cornea’s shape adjusts the eye’s focusing power. This allows for clear vision without the need for glasses or contact lenses.
Who is a Candidate
Determining suitability for laser eye surgery involves a comprehensive evaluation of an individual’s eye health and general medical history. Generally, candidates must be at least 18 years old, as vision tends to stabilize in early adulthood. A consistent vision prescription for at least one to two years, with no significant changes (typically less than 0.5 diopters), is also an important requirement.
Sufficient corneal thickness is another important factor, as the procedure involves reshaping this tissue. Specific corneal thickness requirements vary by procedure and prescription. A minimum of 250 microns of residual stromal thickness must remain after the procedure to ensure corneal stability.
Certain health and eye conditions can affect eligibility. Individuals with uncontrolled autoimmune diseases, such as rheumatoid arthritis or lupus, or those with severe dry eye, may not be suitable candidates due to potential healing complications or worsening symptoms. Eye conditions like glaucoma, cataracts, or keratoconus also typically disqualify a person from undergoing laser eye surgery. Pregnancy or breastfeeding also typically mean delaying the procedure due to hormonal fluctuations affecting vision and the potential impact of medications.
Life After Laser Surgery
Following laser eye surgery, patients can expect a relatively quick recovery, though the full healing process can extend over several months. Immediately after the procedure, vision may be blurry or hazy, and some temporary discomfort, such as itching, burning, or a gritty sensation, is common. These initial symptoms usually subside within a few hours to a day or two.
Most individuals experience significant vision improvement within the first week, often being able to drive and return to work within 24 hours after LASIK. Dry eyes are a common temporary side effect, but symptoms typically improve within weeks or months as the eyes heal. Lubricating eye drops are often prescribed to manage this.
Some patients may also notice glare or halos around lights, especially at night, during the initial healing period. These visual disturbances are generally temporary and diminish as the cornea fully adjusts and swelling subsides, usually within one to three months. Attending all scheduled follow-up appointments and adhering to post-operative instructions are important for optimal outcomes.