If you are tired of wearing corrective lenses to improve your vision, consider laser eye surgery. This procedure reshapes your cornea to help it focus light better on your retina, the light-sensitive part of your eye. But not everyone can have laser eye surgery. One factor that determines your eligibility for this surgery is your corneal thickness.
You measure the cornea's thickness in microns. One micron is one-thousandth of a millimeter. The average cornea is 540 to 560 microns thick.
You can use different methods to measure corneal thickness, including ultrasound pachymetry, optical coherence tomography, or specular microscopy. These methods measure the distance between the front and back of your cornea using sound waves, light waves, or images.
Laser vision correction makes a thin flap in your cornea and uses a laser to remove some tissue from under the flap. This changes how your cornea bends light. The flap then goes back to its place and heals by itself.
Your vision problem determines how much tissue the laser removes. If it removes too much, your cornea might become weak and unstable. This can cause problems like ectasia, irregular astigmatism, dry eyes, or poor vision quality.
Having enough corneal tissue for the flap and the laser is best. A good LASIK candidate usually has a cornea that is 500–600 microns thick. This is good because:
For example, you cannot see far if you have -6.00 diopters of nearsightedness. So, you need to have at least 206 microns of tissue left after the surgery (110 + 16 x 6 = 206). Before the surgery, your cornea should be at least 316 microns thick (206 + 110 = 316).
If you have thin corneas, you might not be able to have regular LASIK surgery. But you still have other options for laser vision correction. These options depend on your specific case. Some of them are:
PRK (Photorefractive Keratectomy)
This surgery does not make a flap in your cornea. Instead, it peels off the cornea's outer layer, called the epithelium, and allows it to heal naturally. This saves more tissue and lowers the risk of ectasia. But PRK takes longer to heal and hurts more than LASIK.
SMILE (Small Incision Lenticule Extraction)
This new surgery uses a special laser to make a small piece of tissue, called a lenticular, inside your cornea and take it out through a small cut. This also saves more tissue and does not make a flap. However, SMILE cannot correct farsightedness; it can only correct nearsightedness and astigmatism.
ICL (Implantable Collamer Lens)
This surgery does not change your cornea at all. Instead, it puts a thin, flexible lens inside your eye, between your iris and natural lens, to fix your vision. This option is for people with terrible vision or very thin corneas that laser eye surgery cannot treat. But ICL has more risks and complications than laser eye surgery, such as infection, inflammation, cataracts, or glaucoma.
Corneal thickness is an important consideration when you decide whether to have laser vision correction. You might not qualify for regular LASIK surgery if you have thin corneas. You still have alternative choices to help you see properly without glasses or contact lenses.
For more on laser vision correction, visit Laser Vision Delaware at our Wilmington, Delaware, office. Call 302-656-2020 to schedule an appointment today.