Almost every person has faced one or other kind of eye problem in life due to infection or as a result of aging but one problem is very prominent throughout the world and that is the vision related problems like myopia (nearsightedness), Hyperopia (farsightedness), presbyopia (reading problem) and astigmatism. Many people use spectacles to correct their vision and since 1950s, contact lenses has also become popular to correct the vision errors.
When vision correction surgery was introduced, it has its own set of drawbacks but the surgical procedure, tools and techniques have evolved extremely and it has become much safer and affordable. Here we will take a look on what is it and how it works
What is vision correction surgery?
It is a surgical procedure to correct refractive errors and sharpen the vision of the patient. The methods used in this procedure has evolved a lot but the fundamental principal remains the same and that is making alteration in the cornea to adjust the vision with precision to correct vision problems so that the patient can see properly without taking help of visual aids.
The earliest method of vision correction involved making a deep incision in the cornea to weaken it so that alterations can be made for the vision correction. In recent years, vision correction is done by reshaping the curvature of cornea so that alteration can be made in the way light enters into the eyes. Besides that, use of artificial lenses which can be implanted surgically are also used to refocus the light so that vision can be sharpened.
Types, benefits and risks of vision correction surgery
Vision correction has become more safe and convenient over the time period and different kinds of surgical procedures have been utilized. Here is the list of some famous vision correction surgery which is:
Radial Keratotomy (RK) – It has been used in 1980s in the United States and it involved creating spoke like incision to flatten the cornea to mainly correct myopia or nearsightedness.
Benefits – The vision remains normal for some years (12 – 13) but then it started deteriorating. Some patients complained rapid decline of vision after a decade of the surgery.
Risks – High risk of complications like glare, regression, fluctuating vision, ghosting, shadows, blurring, starburst, diminished contrast, depth, night vision problems, dizziness, photophobia, rapid degeneration of eyesight have been registered and now this procedure has become obsolete.
Photorefractive Keratectomy (PRK)
– It is the first laser assisted vision correction procedure and used to remove the tissue directly from the eye surface to change the curvature of cornea. It is also known as surface ablation and introduced in 1980s but outside United States. It has got FDA approval in 1995 and it is still in use besides LASIK which is far more popular.
Benefits – The main advantage of this procedure is that the nerve regeneration in the eye surface is much faster with this procedure as compared to LASIK and therefore the chances of dry eyes and other complications has reduced until the healing is done. In addition, there is no risk of surgical flap complication like flap displacement/dislocation because PRK is a surface procedure and is very safe for patients who have thin cornea.
Risks – the patient might experience mild or moderate pain during the healing process. There may be cloudy vision (corneal haze) during the recovery period but it is very rare complication with PRK and it also depends on the surgical assistance utilized for the procedure. Under and over correction complications can also possible with this procedure and therefore one should take assistance of highly experienced surgeon.
Laser-Assisted In-Situ Keratomileusis (LASIK)
There is very little or no discomfort after the surgical procedure and the patient can get clears vision within 24 – 48 hours. It covers a wide range of vision problems and is the most popular procedure used in vision correction. It involves creation of flap on the eye surface but it goes deeper and reaches the stromal layer of the cornea.
Benefits – This procedure is painless, versatile and the recovery period is very short as compared to any other type of vision correction procedure. It has wide range of suitable refraction which ranges from +5.00D to -12.00D and the vision tend to stabilise soon with high correction.
Risks – Although there is no pain during the recovery period but other problems like glare, halos, night vision problem, and dry eyes might be experienced by the patient. The risk of flap complication like flap displacement is always there therefore one should avoid rubbing the eyes vigorously or any activity which can cause eye injury like contact sports (e.g. wrestling, boxing etc.)
Laser epithelial keratomileusis (LASEK)
Like PRK, it works on the Bowman’s layer of the cornea but epithelium is not removed in this procedure. A flap is created to reach the bowman’s layer and after reshaping the cornea with laser, the epithelial flap is placed back carefully over the cornea. After that, a soft contact lens is placed over to protect it during the recovery period.
Benefits – this procedure is suitable for various refractive problems like myopia (nearsightedness), Hyperopia (farsightedness) and astigmatism. It is also suitable for patients with thin corneas and those who have risk of getting facial injury especially eye injury like wrestlers, boxers, baseball players etc. It has fewer complications, less risk of failure and can be performed more than once. It has wide range of refraction which ranges from +4.00D to -8.00D and patients take 3-4 days to recover.
Risks – Patient can experience mild stinging sensation or moderate pain during the first few days of recovery period and corneal haze can also happen. Over and under corrections are also possible with this procedure.
This procedure is very new and used to solve some of the potential complications arise in case of LASIK and LASEK. The procedure is same like LASIK and LASEK means creation of flap but a special cutting tool, a plastic blade called epithelial separator is used to lift the flap.
- Benefits – This procedure is suitable for flatter corneas and less myopia because creating a flap with LASEK is difficult in patients with steeper corneas. This procedure is also suitable for people who have high chances of being hit in the eye like soldiers, police officers, boxers and racquet sports enthusiasts because there is no risk of flap dislocation.
- Risks – The patient might experience some discomfort which is bearable and can be treated with over the counter painkillers. It takes 3-4 days time to recover the vision to normal.
Wavefront LASIK or PRK
– This is the most advanced procedure of vision correction as it utilizes computer generated eye map and gives highest possible sharp vision to the patient. The wavefront analysis can detect and automatically adjust for the vision errors when laser energy is utilized to reshape the cornea.
- Benefits – This procedure is computerized and precisely measures that how light travels through the eyes and where correction is required. It also helps in maintaining contrast sensitivity and reduces the risk of night glare after the surgery.
- Risks – The risks tend to be very rare with this procedure but halos, glare, blurred vision, under or over correction, dry eyes, and infection can happen in some cases.
– This is relatively non invasive procedure and utilizes tiny probe and low heat radio waves to apply “spots” around the periphery of the cornea to steepen it. This procedure is used to correct farsightedness, presbyopia and increase near vision in patients who have undergone LASIK or cataract.
- Benefits – It is relatively non invasive and can help middle age people and the older ones to get rid of reading glasses. It doesn’t involve any tissue removal like PRK or LASIK and takes only few minutes to perform. It is used to correct certain types of astigmatism, improve visual acuity and contrast sensitivity and reduce sensitivity to glare.
- Risks – the near vision benefits of this procedure may not last long but it retains the improved vision without glasses. The patient may experience dry eyes, irritation, light sensitivity, visual problems like starbursts or halos around lights at night time, hazy vision, and double vision.
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