Posted on January 15, 2018
Laser surgery for vision correction surgery, also called refractive surgery, refers to any surgical procedure used to fix vision problems using an advanced laser device. Recent years have seen huge advances in this field. Laser vision correction surgeries reshape the cornea, which is the clear, dome shaped, front part of your eye which is then able to focus light rays properly on the light sensitive part of the eye, called the retina. Other procedures for laser vision involve the placement of a lens inside the eye, or the replacement of the eye’s natural lens, and these are clubbed under the broad category of lens implants.
Each one of the currently available laser refractive procedures promise crystal-clear eyesight without glasses, despite the fact that each of these laser eye surgeries is different. All of these are indicated for the correction of nearsightedness, farsightedness and astigmatism. Each of them has their own distinct advantages and disadvantages, as well as an optimal patient profile. The final decision as to which type of refractive surgery is appropriate for your needs and eye condition will be decided after a thorough evaluation by your ophthalmic surgeon, in consultation with you.
The most popular options are described here in order to assist you in an informed decision making.
- LASIK: LASIK, or laser in-situ keratomileusis, involves the use of a sophisticated, mechanized knife called keratome which creates a corneal flap. This flap is lifted to expose the underlying tissue of the cornea called the stroma. The Excimer laser then ablates the stroma, reshaping using a sophisticated computer guided technology, to eliminate the refractive error. The corneal flap is then repositioned and reattached. This is the most common kind of refractive laser vision correction, and is known to safe and effective in eliminating the need for glasses and contact lenses.
- Wavefront-guided LASIK: This is a newer more technologically advanced form of LASIK in which a three dimensional computer generated image of the cornea is generated. This modulates and controls the reshaping of the cornea with the Excimer. This makes it very much a customised treatment, individualized to the needs of the particular eye under treatment, using the image of the cornea as a guide. Wavefront technology can measure very small abnormalities in the surface of the cornea, and takes as many as 200 measurements, to achieve more effective and safer vision correction than conventional LASIK.
- Contoura Vision Topography Guided LASIK: Contoura vision is the latest FDA approved LASIK eye surgery available in the U.S, and other parts of the world. Dr. Sanjay Chaudhary at Eye7 hospital has been the pioneer of this advanced laser vision correction, and is credited with the first surgery in Delhi. It measures 22,000 points on the cornea, while the currently available wave front-guided LASIK measures around 200 points on the cornea. This implies that the vision correction on a plethora of data points regarding the corneal surface, shape and optics, while other types of LASIK only rely on the current glasses or contact lens prescription. This means that the visual results achieved with this technology are unprecedented in clarity and precision
- Blade-Less Lasik (Femto Lasik, i Lasik, Intralase Lasik, All Laser Lasik, Z Lasik): Bladeless Lasik is yet another innovation of laser vision correction which involves the use of two lasers – first is the Femtosecond Laser, which is used to create an ultra- thin flap in cornea instead of the manual keratome in conventional LASIK. The second Excimer Laser is used to reshape the cornea as in conventional LASIK. No blades are used at any time in the whole procedure. Eye7 hospitals were the first to introduce Femto Blade – Less LASIK in India. The latest acquisition for the group is the Alcon’s Wavelight Refractive Suite which includes the Femtosecond Laser FS200 and EX500 Lasik Laser system delivering the highest standards in precision and visual outcomes.
- SMILE: Small incision Lenticule Extraction or Relex Smile is a variant of the Femtosecond Bladeless Lasik. In this, the Femtosecond laser cuts a slice of corneal tissue, which is then pulled out through a peripheral partial corneal flap. This reshapes the surface of the cornea resulting in correction of certain types of refractive errors.
- PRK (photorefractive keratectomy): In PRK, the corneal flap is not raised. Instead, the outer most covering of the cornea called the epithelium is completely removed to expose the underlying stromal tissue. The laser then reshapes the cornea as in LASIK. The epithelial heals itself in around four days and the patient is provided with a soft contact lens to protect the cornea till the healing is completed. PRK, LASEK, EpiLASEK, and Supra or touchless LASIK are all called advanced surface ablations, ASA, ablations in which no corneal flap is raised.
- LASEK: LASEK, or laser epithelial keratomileusis, is a lot like PRK. In this also, a very thin flap of the corneal epithelium is created, and the underlying stroma is reshaped using the laser. After that, the thin flap is placed back, and kept in place with a bandage contact lens to facilitate healing.
- Epi LASEK: EpiLASEK (which uses a special microkeratome, the Epi-keratome, to remove the epithelial flap, which is replaced at the end of surgery) and SupraLASIK or touchless LASIK (which is surface laser procedure that uses a technologically advanced excimer laser to remove the surface cells before performing the reshape of the cornea) are all ASAs and have the same inherent disadvantages. The obvious drawbacks are the duration of healing, postoperative discomfort, risk of corneal haze and infections. They were considered a better option for patients with thin corneas, but with advent of advanced technology like femtosecond LASIK, and the latest Contoura Vision Topography Guided LASIK, they are becoming less relevant clinically