What is the Purpose of Lasik Eye Surgery?

Laser-assisted in situ keratomileuses (LASIK) is a type of eye surgery done to correct any refractive errors that result in blurriness or hamper the ability to see objects at certain distances. LASIK reshapes the cornea so your vision improves.

Laser eye surgery

The cornea is a clear, dome-shaped tissue that covers the front of your eye. Its purpose is bending or refracting light rays as they enter the eye. This refraction permits light rays to focus exactly on your cornea which is located at the rear of your eye, so you are able to see clearly and sharply.

A refractive error can happen when the cornea is abnormally shaped, an eyeball is too long or short, or an ageing lens. The refractive error does not let rays be properly focused on the cornea, making your vision blurry.

The three main refractive errors corrected by LASIK are:

• Nearsightedness (myopia): when an individual can only see objects that are near clearly (objects in a distance is blurry)
• Farsightedness (hyperopia): when an individual can only see objects that are at a distance clearly (objects that are close by are blurry)
• Astigmatism: when images are blurry no matter whether they are close by or far.

LASIK doesn't correct a refractive error that is presbyopia. This condition causes ametropia and happens because0020of the natural hardening of the lens with age.

LASIK is not a medically necessary procedure. Rather, it's an elective procedure for those who do not want to wear eyewear or lenses.

Criteria and Contraindications

Even if you've been diagnosed with shortsightedness, ametropia, or astigmatism, there are chances of you not being a good candidate for LASIK.

• The basic criteria for going through LASIK surgery include the following:
• You should be of eighteen years and abo
• Your refractive error should not be very large
• Your refractive error should be stable for a minimum of one year (this implies that your eyeglass or lens prescription has remained the same for a year)   

Reasons for not undergoing LASIK surgery are:

• A thin cornea: this is often necessary as the surgeon cuts and reshapes the cornea when performing the LASIK procedure.
• Any corneal ulcerations
• Cornea is cone-shaped (called keratoconus)
• Dry eye syndrome: if you have dry eye, you should not undergo LASIK as a healthy tear film coating is required for proper healing of the eye after LASIK.
• Certain eye diseases, like blepharitis or allergic disease
• If women are pregnant or breastfeeding
• A significant cataract
• Uncontrolled diabetes mellitus 
• Advanced or uncontrolled eye disease like glaucoma
• An uncontrolled autoimmune disorder (like Sjogren’s syndrome)
• Unrealistic expectations from LASIK

Using some medications, like high doses of a steroid (e.g., prednisone), or actively taking part in contact sports where you can get hit in the eye (e.g., boxing), may disqualify you from getting a LASIK procedure done.

Other potential reasons for not undergoing LASIK surgery include:

• If you have a controlled autoimmune disorder (e.g., lupus or arthritic arthritis)
• History of any abnormal wound healing
• If you have had herpetic keratitis
• Diabetes even if it is controlled
• Glaucoma even if controlled 
• If you have already done a refractive surgery

While it is not an outright reason but women with larger pupils are at high risk for having vision issues, like seeing glares or halos around lights, after LASIK eye surgery is done.

Tests and Labs

During your two- to three-hour pre-op appointment your eye doctor is going to review your medical history and medications. The doctor will then perform many refined tests that may provide them with the data concerning your overall eye health.

In addition to helping in deciding if you're an honest candidate for LASIK eye surgery, the data from the tests can guide the physician once they're performing the surgery.

You should stop wearing soft contact lenses for 2 to 3 weeks and hard lenses for 3 to 4 weeks before your consultation. Contact lenses can for a brief period alter the form of your cornea which can affect your analysis.

The surgical tests for LASIK typically are:

Refraction test: Measurements are done to know your prescription, and your eye professional can dilate your pupils so the test is more accurate.

• Dry eye check to judge the composition and volume of the tear film coating of the eye
• Pachymetry is done to measure the thickness of the cornea
• Wavefront analysis: this is often used to know the distortions and irregularities of the eye, referred to as higher-order aberrations. This information is often useful in surgery because it provides knowledge about a patient’s distinctive sensory systems.
• Corneal topography: A computer-assisted tool creates a map of the shape and form of the cornea. This test is often done to see any corneal abnormalities which is a reason to not undergo LASIK surgery.
• Pupil size measurement: Your pupil size can possibly be measured with a special device referred to as an infrared pupillometer.

Separate medical tests, like laboratory tests or an analysis by a patient's regular physician, aren't usually necessary for LASIK surgery.