Laser in Situ Keratomileusis is a procedure that employs the use of a laser under a corneal flap to reshape the cornea i.e. the transparent layer covering the eye. The position under a corneal flap is referred to as ‘in situ’, while the reformation of the cornea is keratomileusis. A specialized excimer laser is used and the procedure is applied to treat refractive errors and enhance vision to do away with the need for eye lenses. Ioannis Pallikaris is widely recognized for the advancement of LASIK in 1991, although the excimer laser had been used in previous years.
The LASIK surgery is an elaborate procedure in which the surgeon first creates a corneal flap with the use of a micrkeratome. This slight flap is opened to reveal the corneal tissues, after which the cornea is restructured into a predetermined pattern that is unique for each individual using an excimer laser. The corneal flap is then replaced on the corneal tissues.
Refractive errors occur in the eye when the power of the cornea and that of the lens are not compatible with the physical length of the eye, and this surgery is used to correct these occurrences.
a) Short-sightedness/Myopia – In these cases, the refractive error causes distant objects to appear blurry and out of focus while closer objects remain more apparent.
b) Long-sightedness/Hyperopia – The refractive error in these cases causes objects that are close to the eye to be blurry and out of focus, while those at a distance remain clearer.
c) Astigmatism – Thos refers t the disfiguration of either the cornea or lens shape. This results in multiple images appearing on the retina, and objects appear blurry whether they are near or far. It is common for people to have a blend of myopia or hyperopia with astigmatism.
The Effects of Spectacles and Contact Lenses
Eye lenses are employed to bend light rays in a bid to recompense for the refractive error involved. They are not corrective measures, and eye surgery is purposed to eliminate the need for such lenses.
Aging and its Effect on Vision:
When we are young, our eyes can alter their shape and power so that we can focus on close objects naturally as our eye lens changes power. With age, the lenses of our eyes stiffen and their aptitude to change shape and power is reduced, resulting in a condition referred to as presbyopia. This gives rise to the need for spectacles designed for reading, and doing other activities that require us to see objects that are nearer to the eye. While LASIK cannot be used to treat presbyopia, some other techniques can work e.g. monovision, which treats one eye to see closer objects better while the other is treated to see distant objects better.