LASIK, an acronym for Laser-Assisted In Situ Keratomileusis, is a surgical procedure that enhances vision. This outpatient refractive surgery precisely reshapes the cornea, the clear, dome-shaped front surface of the eye. Its goal is to change how light enters the eye, allowing it to focus accurately onto the retina. By correcting the eye’s focusing power, LASIK aims to reduce or eliminate the need for glasses or contact lenses, offering improved visual clarity.
Vision Problems LASIK Addresses
LASIK is effective in correcting common refractive errors that cause blurred vision by altering the cornea’s curvature. These conditions include nearsightedness, farsightedness, and astigmatism. Each of these refractive errors stems from an imperfect eye shape that prevents light from focusing directly on the retina.
Nearsightedness, or myopia, occurs when distant objects appear blurry because light focuses in front of the retina. For myopia, the cornea is typically too steeply curved or the eyeball is too long. LASIK addresses this by using a laser to subtly flatten the cornea, redirecting light rays to focus correctly on the retina, thereby sharpening distance vision.
Conversely, farsightedness, known as hyperopia, causes nearby objects to appear unclear, as light focuses behind the retina. This happens when the cornea is too flat or the eyeball is too short. LASIK corrects hyperopia by carefully steepening the central curvature of the cornea. This adjustment enables light to converge on the retina, improving clarity for close-up tasks.
Astigmatism causes blurred vision at all distances due to an irregularly shaped cornea, which is more football-shaped than spherical. This uneven curvature causes light to scatter rather than focus to a single point on the retina. LASIK smooths these irregular corneal curves, creating a more uniform surface that allows light to focus properly, reducing visual distortion.
Vision Problems LASIK Does Not Address
While LASIK effectively corrects various refractive errors, it does not provide a solution for all vision impairments. Certain eye conditions are not related to corneal shape and thus fall outside the scope of this procedure.
Presbyopia, which is age-related farsightedness, is a common condition that LASIK does not correct. This condition occurs as the natural lens inside the eye stiffens and loses flexibility, making it difficult to focus on close objects, usually starting around age 40. Since LASIK reshapes the cornea and does not affect the eye’s natural lens, it cannot reverse this age-related change. Some specialized approaches, such as monovision LASIK, aim to address presbyopia by correcting one eye for distance and the other for near vision.
LASIK is also not designed to treat severe vision loss or blindness caused by underlying diseases unrelated to refractive error. Conditions such as advanced glaucoma, cataracts, or severe retinal diseases require different medical or surgical interventions. For instance, cataracts involve clouding of the eye’s natural lens, a problem LASIK cannot resolve. Similarly, diseases affecting the optic nerve or retina are beyond the capabilities of corneal reshaping.
Certain corneal conditions, like keratoconus, where the cornea progressively thins and bulges into a cone shape, are contraindications for LASIK. Performing LASIK on such eyes could worsen the condition. Severe dry eye, if not managed, can also complicate healing and outcomes after LASIK, making it unsuitable until adequately treated.
Who is a Candidate for LASIK?
Determining suitability for LASIK involves evaluating several factors beyond simply having a refractive error. A thorough eye examination and medical history review are necessary to ensure the procedure is safe and effective. These criteria help identify individuals who are most likely to achieve successful outcomes.
Most candidates are 18 years or older, with some specialists recommending waiting until at least the mid-20s. This age requirement ensures that the eyes have reached ocular maturity and that the vision prescription has stabilized. A stable prescription, meaning no significant changes for at least one to two years, is important for lasting results.
Overall eye health is important. Candidates should have healthy eyes free from active infections, severe dry eye syndrome, or progressive eye diseases. Adequate corneal thickness is important, as the procedure involves removing a small amount of corneal tissue to reshape it. If the cornea is too thin, LASIK may not be an appropriate option.
General health plays a role in candidacy. Certain systemic health conditions, such as uncontrolled diabetes or autoimmune diseases like rheumatoid arthritis, can impair healing and increase the risk of complications. Pregnancy and nursing are also temporary contraindications due to hormonal fluctuations that can affect vision stability.