What is Photorefractive Keratectomy (PRK)?
All laser vision correction surgeries work by reshaping the cornea, or clear front part of the eye, so that light traveling through it is properly focused onto the retina located in the back of the eye. There are a number of different surgical techniques used to reshape the cornea. During PRK, an eye surgeon uses a laser to reshape the cornea. This laser, which delivers a cool pulsing beam of ultraviolet light, is used on the surface of the cornea, not underneath a flap on the cornea, as in LASIK.
Only an ophthalmologist can confirm that you qualify for PRK eye surgery by conducting eye exams to test your corneal thickness, measure your refractive errors, and check for other vision problems that could prevent you from being a suitable candidate for treatment. Patients who are not good candidates for LASIK surgery are often good candidates for PRK surgery. Since PRK does not require the creation of a corneal flap, this procedure is often preferable for patients who have a difficult time sitting still or those with inadequate corneal tissue.
To be a good candidate for PRK, you should:
Be at least 18 years old. This ensures that the eye has matured and developed properly.
PRK surgery cost in Iran start from $300.
prk cost in iran
The PRK procedure differs from the LASIK procedure, in that, no flap is created in the PRK procedure. The procedure includes the following steps.
Please Note: During this procedure, scalpels are not used and neither are any incisions made.
3. The surgeon will carefully remove the complete upper layer of your cornea (epithelium) and then use targeted laser or excimer laser to correct and reshape the cornea.
Please Note: The epithelium regenerates within 3 to 5 days.
4. After the surgery, a clear contact lens which acts like a bandage will be placed over your eye for 4-6 days.
5. The same process is repeated with your other eye.
PRK surgery is performed to correct myopia (nearsightedness), hyperopia (farsightedness) and astigmatism. This surgery is considered to be ideal for people with thin corneas.
Following the procedure, there could be irritation in the eyes, coupled with watering for at least 3-4 days.
Other side-effects can include infections, inflammations, scarring, and dry eyes, within the first week after the surgery, when the cornea is healing. These conditions can be treated with antibiotic drops.
Though highly rare, occasionally, in some patients irregular astigmatism may occur after PRK surgery. This can be treated with an additional minor procedure.
Another side effect that may occur is overcorrection or undercorrection of eyesight. When overcorrection occurs nearsightedness gets altered to farsightedness, and it is vice versa for undercorrection. These residual power error conditions can be corrected through enhancement or retreatment surgeries. If however, your cornea is too thin or steep the surgeon will advise you to not go in for additional surgeries and will instead prescribe you glasses or lenses to correct your vision.
Corneal haze is another complication that can arise after a PRK surgery. This condition usually resolves itself as the eye heals, but can take from 6 months to one year, therefore doctors prefer to treat it with medication or more laser treatment.
A more aggressive complication which is uncommon, but can occur post a PRK surgery is corneal ectasia. Corneal ectasia is an umbrella term for a group of eye disorders characterized by abnormal corneal thinning or irregular thickening from the centre of the cornea to the periphery. The most common among these disorders is keratoconus.
Corneal ectasia can occur if the cornea is too weak.
It has been observed that corneal crosslinking treatment helps to arrest conditions such as keratoconus. In this procedure, custom-made riboflavin drops saturate the cornea, which is then activated by ultraviolet light. According to studies, this increases the amount of collagen cross-linking in the cornea thus strengthening the cornea.
This method, however, is not currently FDA approved.
Unlike LASIK surgery, after the PRK surgery, there are no flap-related complications.
Prior to going for an evaluation by an ophthalmologist, it is recommended to stop using contact lenses for four weeks and switch to wearing glasses. Wearing contact lenses over a long period of time changes the shape of the cornea. The cornea then takes a long time to assume its natural shape. It is similar to how a watchband leaves an imprint on the hand when worn for a long time. Therefore, an evaluation and surgery based on the cornea which has not assumed its natural shape can have negative implications.
During the evaluation you need to discuss in depth with your doctor about whether you are a good candidate for PRK surgery, what are the alternative surgeries you can opt for, what are the risks and complications involved, what can you expect after the surgery, and what are the pre and post surgery guidelines.
On the day of the procedure do not wear any jewellery, and do not apply any cream, and make-up, or use any perfume. You may be asked by the doctor to frequently scrub your eyelids and lashes gently, 2-3 days before the surgery, to get rid of any accumulated oil or debris.
You need to discontinue any cold or allergy medicines at least 4 days prior to the surgery. If you take any blood thinners you need to check with the doctor whether you need to stop taking them for some time prior to the surgery.
You will need to stop smoking and drinking alcohol 48 hours before and after the surgery.
On the day of the surgery, you should not take insulin if you are a diabetic. You will need to arrange for a driver to take you home after the surgery.
not rub your eyes.
avoid any form of strenuous exercise, such as heavy lifting, or swimming, that could result in eye injury for at least a month
avoid driving till your vision is absolutely clear.
wear sunglasses for a week after the surgery, even while indoors. (Ideally, glasses should be worn for the first six months after the surgery to avoid UV rays and avoid haze formation.)
avoid applying any makeup or lotion on the face
avoid any situation involving dirt for 7-10 days.
not to get face wash or soap in your eyes while washing your face, or showering (In fact, you need to keep water and shampoo away from your eyes for at least 7 days after the surgery.)
avoid swimming and hot tubs for at least a month after the surgery.
apply eyedrops in your eyes at regular intervals as prescribed by the doctor.
The initial vision recovery period could take up to 4 days during which you will also experience mild discomfort in the eye.
You might experience sensitivity to light, which is accompanied by the feeling of tearing, or at times the feeling of a foreign body in the eye. This is the period when the epithelial layer of the cornea is regenerating. The discomfort vanishes by the fourth day. The vision, however, remains cloudy.
It may take 4-6 weeks for your vision to become clear so that you can start performing finer activities or detailed tasks.
After a period of six months, the vision stabilizes and becomes absolutely clear.
It usually takes 3 - 6 months to completely recover from a PRK surgery and achieve clear vision.
In most cases, a PRK surgery is sufficient for vision correction. However, in some cases a person might not achieve the desired optimal result from the surgery, in such cases, the doctor may advise a second PRK procedure to further enhance the results.
The PRK procedure permanently corrects the shape of the cornea, however, this does not stop the natural vision abnormalities that occur with aging.