Spectacles are an aid to see better, however, not everyone needs it. It is required because the dimensions of the eye do not
bring the rays of light entering the eye to a clear focus on the retina.
This could be because of the length of the eye, longer eye causes myopia or short sightedness or need for “minus” power glasses, shorter eye causes hyperopia or long sightedness or “plus” power glasses. The plus or minus power is called spherical power. The eye is like a ball, but not a perfect sphere, so there is a curvature and variations in it causes astigmatism or “cylindrical’ power. Many have a combination of either plus or minus spherical power with cylindrical power. While the glasses helps an individual to see clearly it is viewed as a handicap by some, becomes a bane in some professions, is cosmetically unacceptable by many others, or is viewed as a recurrent cost by some. What are the options if a person wants crisp vision and still not want to wear glasses?
Contact lenses :
Time tested, easy to use, daily/fortnightly/monthly disposable options are available, can be bought in colours too for the fashion conscious.
A certain amount of care is required, which if meticulously followed will not give any long term problems.
LASIK : An acronym for the procedure called Laser Assisted in-Situ Keratomileusis. A procedure where the shape of the cornea (the transparent front structure of the eye)
is altered with extreme precision to correct the refractive error and without causing any damage to the nearby structures.
In this procedure a flap is raised of the cornea and the laser (based on numerous calculations) is applied to the bed and the flap is reposited.
The flap is raised with the help of a microkeratome. Recovery is rapid and spectacle free vision can be expected for a life time.
The primary advantage for the use of femtosecond lasers in corneal refractive surgery is the improved safety over microkeratomes in creation of the lamellar flap. Additional advantages includes
- Increased precision
- Ease of surgery
Femtosecond lasers allow for customization of the flap for each patient. In addition to producing reliable flap thicknesses, the flap diameter can be selected to one-tenth of a millimeter. Femtosecond lasers are (state-of-the-art) instruments that offer more surgical precision than current manual techniques. PRK (Photorefractive Keratectomy) It was the original kind and is still sometimes used. It involves gently scraping the surface layer off the cornea and then using a laser beam to re-shape it. The healing takes a few days more than the LASIK procedure described above but in some corneal conditions this is safer and also gives good results. Your eye surgeon is the best person to help you decide which procedure will suit your eyes better. Epi LASIK ( Epithelial Laser-Assisted In-Situ Keratomileusis: EPI LASIK) It is a procedure, which combines the advantages of PRK and LASIK, Epilasik involves the use of an epikeratome, where only the superficial epithelial layer of cornea is removed. Wave front-guided/ Wave front optimised LASIK It is also referred to as custom LASIK or wave front LASIK, is similar to conventional LASIK, except that in addition to treating a patient’s basic refractive error, specific distortion in a patient’s eye (high order aberrations) can also be treated. ICL implantation
There are some eyes which are not suited for any of the above mentioned laser procedures to correct the “power” in them. These patients can undergo ICL (Intraocular Collamer Lens) placement within the eye(s) which is an intraocular procedure unlike LASIK which is a procedure on the surface of the eye. ICL surgeries today have a very high success rate and keep the persons spectacle independent. The added advantage is that the procedure is reversible. Specific tests are needed to confirm the eye is suitable to have an ICL placed within.
This is a procedure where the non-cataractous (crystalline) lens of the eye is removed by phacoemulsification and a multifocal / trifocal / EDOF lens is placed giving spectacle independent vision for all ranges. This is an intraocular procedure and the benefit is that a future cataract surgery will not be required.