About Lasik and Laser eye surgery procedures
The field of ophthalmology has seen great progress in the last few years and there has been a lot of talk about the different eye surgeries – how they have improved, become more and more painless, quick and effective. So much so that terms like LASIK have become part of the everyday lingo. But do we really understand what these terms that have been floating around so carelessly actually mean?
Like any good health professional will advise you, any medical prescription, suggestion or opinion needs to be verified with a trained practitioner before being adhered to. In case of LASIK or any other procedure, we are actually talking about vision correcting surgeries. Just like a Paracetamol may not be apt for curing a stomach ache, LASIK is not the panacea of all vision related problems.
Before getting into corrective surgeries, let us understand the working of the eye, the problems and then the corrective procedures.
As any good eye care professional in Kolkata or elsewhere will tell you, the human eye works like an extremely sophisticated camera. The light rays enter the human eye through the cornea, which acts like a window for the eye. The entire light coming to the cornea is bent due to the refractive power of the cornea at certain angles, so as to enter through the pupil located in the iris. The iris can be thought of working like a shutter in the camera, allowing only the correct amount of light to enter. In the normal working conditions, as light passes through this camera like arrangement an image of the object is formed on the retina, which is known as seeing the object.
The most important part of this entire complicated arrangement is the correct refraction of light by the cornea. If this first step has issues, there will be problems in seeing the objects. For example – if the light rays are refracted in a way that the image is formed before reaching the retina, a person will not be able to see far off objects.
The vision related issues are generally because of some or the other aberration in the curvature of the cornea. The most commonly known issues are
- Myopia (Short sightedness – image is formed before the light reaches the retina)
- Hyperopia (Far sightedness – image is formed behind the retina)
- Astigmatism (Asymmetric curvature of the cornea)
- Presbyopia (Aging of the lens)
Since most of the vision related problems are related to the curvature of the cornea, the corrective eye surgeries involve correcting the curvature of the cornea. Most common surgeries for correcting the curvature of the cornea include making incisions to the cornea. These incisions were earlier made using diamond scalpels or other instruments.
With the advance in the laser technology and its extremely precise nature, this has become a popular choice for making incisions in eye as well as other surgeries. Some of the corrective eye surgeries for refractive errors using laser are as follows
- Laser in-situ keratomileusis (LASIK)
The most recent and one of the most popular surgical methods LASIK is the biggest reason for the increase in the number of people ready to undergo corrective eye surgery. Also, LASIK can be used to treat a greater range of problems like myopia, hyperopia as well as astigmatism.
Before going for LASIK, the advanced method of wavefront guided LASIK actually measures the optical distortions in the patient’s eye. This helps the surgeon to get a precise idea of the corrective measures required. During the surgery, two critical tools are used – computer controlled excimer cold laser and femtosecond laser.
With their help, the surgeon cuts a flap in the cornea and removes a thin layer of tissue depending on the optical distortion. The flap is then replaced without stitches and it reattaches to the cornea within minutes. Due to its precise nature, it is very less painful and has faster recovery time. Hence, LASIK has replaced many previous refractive eye procedures.
- Photorefractive keratectomy (PRK)
It is similar to LASIK with the major difference being the amount of incision made. In PRK, tissues are removed only from the outer surface of the cornea. It is hence performed for treating mild to moderate myopia.