REFRACTIVE ERRORS- AND THEIR TREATMENT
The cornea and lens of the eye focus light like a camera lens to form an image on the retina. The cornea, where light first enters, provides about two thirds of the eye’s focusing power, and the lens inside the eye provides the other third. Variations in the shape of the eye are perfectly natural, although degrees of variation affect how well we see.
Laser vision correction can be used to treat three of the most common focusing problems: myopia (nearsightedness), hyperopia (farsightedness), and astigmatism.
Myopia (nearsightedness) – Myopia, or nearsighted vision, results when the eyeball is too long or when the front and center surface of the eye (cornea) is curved too much. Light will focus in front of the retina, causing blurred vision.
Hyperopia (farsightedness) – Hyperopia, or farsighted vision, occurs when the eyeball is too short or the corneal curvature is too flat, causing light to focus behind the retina. Hyperopia is sometimes confused with presbyopia, an age-related change in vision causing the need for reading glasses.
Astigmatism – Astigmatism occurs when the eyeball is oblong (oval). In this condition light cannot be focused properly anywhere. Astigmatism is often present along with myopia and hyperopia.
Presbyopia – Patients over 40 to 45 years of age may have difficulty with their reading vision, while their distance vision is clear. This happens as the natural lens loses its ability to change the eye’s focus from distance to near. Use of reading glasses helps the eyes to re-focus after LASIK, PRK, or Epi-LASIK.
What is Refractive Surgery?
The term refractive surgery describes various procedures that modify the refractive error of the eye. Most of these procedures involve altering the cornea and are collectively referred to as keratorefractive surgery.
Refractive surgery may be considered when a patient wishes to be less dependent on spectacles or contact lenses, or when there are occupational or cosmetic reasons not to wear spectacles. Refractive surgery is an elective procedure. Speak to our ophthalmologists for the best refractive surgery option for your eyes!
What is Refractive Surgery for Myopia?
The most commonly performed procedures for low to moderate myopia utilize the excimer laser, which was first approved for this purpose by the United States Food and Drug Administration (FDA) in 1995. Photorefractive Keratectomy (PRK) was the first procedure performed; subsequently, laser in situ keratomileusis (LASIK) has become the most commonly performed keratorefractive surgery. Other keratorefractive procedures to correct low to moderate myopia currently include laser epithelial keratomileusis (LASEK or Epi-LASIK).
What is LASIK?
LASIK, which means Laser In Situ Keratomileusis, is a surgical procedure in which a hinged flap consisting of corneal epithelium and superficial stroma is created. After the corneal flap is created, a tissue-ablating excimer laser is used to reshape the exposed corneal stroma, and the flap is repositioned. The anterior corneal surface can be altered to modify a patient’s refractive error by varying the degree of corneal tissue removal beneath the flap. The corneal tissue has natural bonding qualities that allow effective healing without the use of stitches.
What is Photorefractive Keratectomy or PRK?
In PRK, the epithelium is removed either mechanically, chemically, or by laser. After removal of the central corneal epithelium, the excimer laser is used to remove corneal stroma over the entrance pupil. The laser can alter the anterior corneal curvature to modify a refractive error by varying the ablation pattern.
High myopia is less likely to be fully corrected by keratorefractive surgery than low to moderate myopia. Because of the greater functional impairment experienced by highly myopic patients, however. A good option for high myopia is the Phakic Intraocular lens.
Ask your surgeon about the FDA approved Implantable Collamer lens (ICL)
With over 700,000 procedures completed worldwide, be the next to break free from the hassles of glasses! Think of it as an implantable lens that works with your natural eye to correct your vision. The premium lens material, Collamer, creates options for a much wider range of prescriptions that can free you from glasses and contact lenses.
Speak to our ophthalmologists to know the best refractive surgery option for your eyes.
