Today’s technology allows for many alternatives to correcting refractive errors than simply wearing glasses. Patients with myopia, hyperopia, astigmatism, presbyopia, and even keratoconus have more options than ever to maximize their vision. Where glasses and contact lenses are certainly the most common means of vision correction, there are many other options that may apply.
LASIK (Lasar Assisted in Situ Keratomileusis)
Lasik surgery, sometimes called refractive surgery or laser vision correction, has become the most popular and most frequently performed elective surgery in North America. Laser surgery is used to correct the most common refractive errors including myopia, hyperopia, and astigmatism.
How Lasik works
Lasik procedures are conducted by ophthalmologists, medical doctors who specialize in surgery of the eye. The surgeon will create a protective flap to access the inner corneal tissue. Once the tissue is able to be accessed, the inner layers of the cornea are reshaped by computer controlled pulses of laser light. The reshaping of the cornea improves, and often eliminates the need of a corrective prescription. Once the tissue is reshaped, the surgeon replaces and aligns the flap to its original position.
Lasik procedures are not correct for everyone, but there are several different types that may better suit a patients needs. Custom Lasik is the most popular and desirable Lasik procedure. By using Wavefront Technology, the specific manner of which light travels is detected and mapped. This technology provides information about the specific characterizations of your eye. This data can then be used by your surgeon to increase your success rate and enables optimal results.
Bladeless Lasik offers a full customization of all aspects of your Lasik procedure, including creating a custom flap during procedure in order to provide optimal results.
LASEK (Laser Assisted in-Situ Epithelial Keratomileusis)
Sometimes referred to as epi-LASEK, this procedure is ideal for candidates who had previously been turned down for Lasik procedures due to thin or irregular corneas.
How Lasek Works
During a LASEK procedure, your surgeon will remove the top layer of the cornea as a flap-like (or epithelial) sheet before reshaping the inner tissue of the cornea with computer controlled lasers. The flap is then replaced and the patient is given soft contacts after the procedure in order to protect the cornea. LASEK differs from LASIK by means of procedure. In a normal Lasik surgery, a flap is created by the surgeon using a microkeratome. In Lasek, the flap is created by loosening the tissue covering the cornea and allowing it to heal after the procedure.
PRK (Photorefractive Keratectomy)
PRK is an elective surgery to corrective for refractive errors. Previous to the development of Lasik, PRK was the most popular option for vision correction. PRK surgery involves reshaping the surface curvature of the eye to improve or eliminate the need for prescriptions. PRK is ideal for patients with thinner corneas or with vocational or sports-related limitations where the corneal flap is contraindicated.
How PRK Works
PRK differs from Lasik in that the surgeon does not create a flap. Custom PRK uses Wavefront Technology to map aberrations in the eye and allows the surgeon most data to make PRK successful. PRK surgery is preformed with no incisions; instead a calibrated laser removes the epithelium layer and allows the surgeon to access the inner tissue of the cornea. Once that tissue is accessible, the lasers will reshape the curvature of the eye. Deeper layers of the cornea remain untouched and the epithelium layer will regrow in about 5 days.
Healing time from PRK procedures tends to be slower than with Lasik, and can cause some discomfort and vision impairment while healing.
CK (Conductive Keratoplasty)
Conductive Keratoplasty is a procedure using radiofrequency (RF) energy to reshape the cornea. CK is ideal for patients with presbyopia or farsightedness over the age of 40. CK procedures can improve your near vision, allowing you to decrease your dependency on reading glasses.
How CK Works
CK works by reshaping the surface of the eye, changing how light is focused. By shrinking corneal tissue with controlled release of RF energy, light is redirected to the retina. This reshaping technique steepens the cornea and allows for the correction of near vision. This RF energy is released in the form of a tiny probe that circles around the cornea to shrink small areas of corneal tissue.
Implantable Collomer Lenses (ICL) and Phakic Intraocular Lenses (IOL)
Ideal for patients who have very high prescriptions that are not able to be corrected with refractive surgery, ICLs are implantable contact lenses that are surgically implanted into the eye and allows for additional focusing power without removing any tissue. Unlike cataract surgery, the natural lens is preserved. ICL offers permanent vision correction.
Intraocular Lens (IOLs) are implanted after refractive lensectomy (removal of the natural lens) in order to correct for many prescriptions that are not able to be corrected with other refractive surgeries. Phakic IOLs are inserted in the eye and allow light to be directed properly onto the retina. An incision is made onto the eye, and the Phakic IOL is placed directly behind the iris.
Vision Correction – Non Surgical
Orthokeratology (ortho-k) is a non-surgical procedure that can reverse the effects of nearsightedness on your vision. Basically, your eye doctor fits your eyes for special contacts made to exactly balance the specific error in your vision. By using a special machine, your eye doctor will “map” the surface of the cornea and use that data to fit you for a type of contact called a gas permeable lens. These lenses are harder, more rigid, and made out of a material that allows more oxygen to pass through the lens to the eye than the average soft lens. The rigidity of the lens is what makes this procedure more permanent than the normal contact lens fitting. The harder lenses actually alter the shape of the cornea, for a limited amount of time, so that you can actually go without them and still be able to see clearly. The procedure is done slowly, with incremental adjustments of the prescription, until the shape of the cornea is more like a normal, healthy eye, and contacts are no longer necessary. It is important to wear them frequently, however, because the reshaping of the eyes is temporary. They will revert back to the irregular shape that causes less-than-perfect vision if you are not diligent about wearing your lenses.
Generally, vision is improved and clear for about a day without the lenses, and after that the eyes will need to be re-shaped. New technological findings in the realm of contact lenses have made it possible for gas permeable lenses to be suitable for overnight wear, so ortho-k has surged in popularity as of late. Patients are now able to wear their contacts while they are sleeping and remove them during waking hours, living unbothered by some of the inconveniences of contact lenses.
The ideal candidate for ortho-k is a nearsighted person with a refractive error of less than -4 or -5, and little to no astigmatism. This procedure is not probably adequate for someone who wants to eliminate contacts altogether—he or she may be looking for LASIK surgery—but it is great for someone who cannot or is unwilling to pay for LASIK, but would like to achieve some of the benefits of lens-free vision.