Posted on December 12, 2017
LASIK (laser in-situ keratomileusis) is the most commonly performed laser surgery for freedom from glasses. It is safe and effective not only for correcting nearsightedness, but also far sightedness and astigmatism.
Nearsightedness, called myopia by your doctor, is an error of refraction in which the rays of light entering the eye are not focused on the retina, which is the light sensitive part of the eye. The parallel rays of light fall short of the retina, as the eye ball is elongated. Your vision, therefore, is perfect for near objects, but is blurred for distance. This may be because your eyeball is longer than normal or when the curve of the cornea is too sharp.
To remedy this, your doctor asks you to use concave lenses, or lenses with a negative dioptric power to focus the light on to the retina again. These lenses can be either in your spectacles, or contact lenses.
For those patients who want better vision with using either glasses or contact lenses, there are several surgical options available. The most popular refractive eye surgery, for removal of glasses, is called LASIK.
Having a refractive surgery means no more dependence on spectacles or corrective lenses. LASIK surgery has a very good track record in this especially because complications are rare, and most patients are more than happy with the visual results.
What is LASIK:
During LASIK, your surgeon will make a small flap in the cornea, the dome shaped, transparent part of the eye. This may be done using a manual keratome, or by laser as in blade free LASIK surgery. After this, the surgeon ablates a part of the cornea during the next part which is the actual laser procedure itself. This laser flattens the cornea, without damaging any surrounding tissue, using a sophisticated computer guided program, to make it such that all light rays are focused directly on the retina.
There are several variations in the technologies available for laser vision correction, including techniques in which a very thin flap is raised or no flap is raised, or the flap is raised using a laser. Each of these has a unique set of advantages and disadvantages.
Are you eligible for LASIK:
If you’re tired of wearing eyeglasses or contact lenses, you may want to discuss the possibility of laser vision correction with your doctor.
Before answering that question, your doctor will need to evaluate your eyes comprehensively. These include measurements of the refractive power of the eye, and a detailed dilated evaluation of the retina, as well a measurement of your corneal curvature and thickness.
Your doctor will also want to look at your previous prescriptions of spectacles to insure that your vision has been stable for at least a year. Since the refractive power of the eye changes during the growing years, patents less than eighteen years of age are not considered suitable for LASIK.
As a rule of the thumb, LASIK is most appropriate for people who have a mild to moderate degree of nearsightedness and astigmatism.
In case of the following disorders of the eye, you may not be eligible for LASIK:
- Keratoconus, which is a progressive eye disease which results in corneal thinning and protrusion.
- Keratitis that is, any corneal infection.
- Uveitis, which is an inflammation of the brown/ blue part of the eye.
- Eye injuries or lid disorders.
- Dry eyes, if severe.
- Large pupils, especially if large in dim light.
- Glaucoma, since the surgical procedure can raise your eye pressure, which can make glaucoma worse; and also because the eye pressure measurement after LASIK is less reliable during serial follow up.
Your eye surgeon will also want to rule out certain general health concerns which may have an adverse effect on visual results after LASIK.
- Pregnancy and breast-feeding may cause temporary fluctuations in the refractive power of the eye, and consequently in your vision. Your doctor will advise you to wait until around six months after stopping breast feeding before considering LASIK.
- Any autoimmune diseases and connective tissue disorders like rheumatoid arthritis, lupus etc.
- Immuno-suppression due to HIV infection or any disease that requires immuno-suppressive therapy.
- Diabetes, especially if uncontrolled.
That said, LASIK is one of the most effective and safe refractive eye surgeries in the world, and the evolving current technologies have made it even more efficacious. Your doctor is the best judge for deciding which variant of laser refractive surgery will be best suited to your eyes, and will be happy to explain his or her reasons for choosing one over the other.