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All about Lasik eye surgery

 

Lasik stands for laser in-situ keratomileusis, is a type of refractive surgery that reduces nearsightedness and farsightedness by reshaping the cornea to achieve clear vision without contact lenses or spectacles. Lasik is a surgical technique which has found its way into many forms of entertainment in films and TV shows, but also it can improve people’s lives.

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 Lasik eye surgery involves two procedures:

-The procedure to treat nearsightedness is called photorefractive keratectomy (PRK). In this procedure, a laser is used to remove some of the clear corneal tissue and reshape the cornea.

-The procedure for farsightedness is called laser-assisted in situ keratomileusis (LASIK). LASIK uses an instrument called a microkeratome to make a flap in the corneal tissue. A laser is then used to remove tissue from underneath the flap and finally the flap is replaced in its original position. 

The whole operation takes about 20 minutes per eye with local (topical) anesthesia. The duration of the procedure varies with the surgical method and with the condition of the cornea. The patient’s vision is usually corrected immediately after surgery. 

Why Is LASIK Done?

LASIK surgery may be an option for a single correction, or it may be combined with another procedure. Over 10 million people worldwide have now had LASIK.

 

LASIK is done to treat myopia (nearsightedness) and astigmatism, conditions which are corrected by changing the shape of the cornea; hyperopia (farsightedness), which is corrected by flattening the cornea; and presbyopia (a loss of focusing power in older age), which is corrected by changing the position of the eye's lens. LASIK may also be used to correct a condition known as keratoconus, which causes progressive thinning of the cornea and severe nearsightedness. 

How Is LASIK Performed?

LASIK is usually done as an outpatient procedure. Before the operation, a topical anesthetic is applied to the eye to numb it. The patient then lies on his or her back and looks up at a machine (called a laser) that uses a highly focused beam of light to reshape the cornea. This powerful beam can cut tissue without touching it, leaving very fine incisions. The entire procedure takes 20 minutes and is done under local anesthesia by placing numbing drops in your eye; you will be awake and able to see during the operation, but you will not feel pain during LASIK surgery since there are no incisions on the cornea itself. 

What Happens After LASIK Surgery?

The patient may resume normal activity immediately after surgery, although some people experience discomfort and redness of the eye. Some patients are able to drive within hours after LASIK surgery, while others must take an extra day off work. Discomfort can be controlled with pain relievers. Your eyesight will improve quickly after the procedure and most people are able to see well without their glasses or contact lenses within one week. In some cases, your vision will continue to improve for up to three months after the procedure. You should have your first follow-up visit within two weeks of LASIK, but if you’re seeing well, you can go back earlier if you wish. 

Although LASIK is considered safe and effective, complications can still occur. Your doctor will review potential problems before the procedure, but here are some of the most common potential complications:

 

· Over the Edge Flap (OTE) - During LASIK surgery, the flap may be created over too great a portion of the edge of the cornea. This leads to a condition called over-the edge flap that can cause unclear vision, glare and halos from light sources.

 

· Infection – Rarely, infections affect patients after they have had LASIK. Symptoms include redness, swelling or other discharge from one or both eyes; decreased vision may also be experienced.

 

· Under the flap (epithelial ingrowth) – LASIK surgery results in damage to the epithelium, which is the top layer of cells in the cornea. In rare cases, this damage can cause cells from the cornea to grow under the flap, resulting in a condition called epithelial ingrowth. The symptoms of epithelial ingrowth after LASIK are pain and redness; vision may also decrease.

 

· Undercorrections or Overcorrections – In rare cases, LASIK can result in undercorrecting or overcorrecting vision. In undercorrecting, you may still be able to see clearly without glasses or contact lenses but close objects appear blurry. In overcorrecting, you may need glasses or contact lenses in order to see well.

 

· Dry Eyes – Dry eyes are a common side effect of LASIK, which can last for months after surgery. Your doctor can prescribe artificial tears to help relieve dry eye symptoms.

 

Many people have found that LASIK has improved their lives by enabling them to live without wearing glasses or contacts, and others find the procedure has brought back their ability to participate in activities they couldn’t enjoy before LASIK, such as driving at night or playing sports. 

LASIK is also an excellent alternative for those who have had less than optimal results from contact lenses. If you are tired of shopping for new glasses, tired of cleaning your glasses and tired of having them slip down your nose and can’t imagine living without your favorite sunglasses, LASIK may be the right choice for you. 

You can compare a few benefits and Risks of LASIK surgery:

Benefits of LASIK surgery:

· No need for glasses or contacts 

· Quick procedure that takes 20 minutes per eye and is performed in the doctor's office with local anesthesia (numbing drops) 

· Immediate improvement in vision, with visual accuracy usually seen within 1 week after surgery. Many patients notice continued improvement up to 3 months. 

· Retain the ability to see better at night and in dimly lit areas. This is a benefit of reduced need for reading glasses or bifocals. Although some patients do still use reading glasses after LASIK, they are able to choose different styles than they could before, such as ones with thinner lenses. 

· Cannot be easily removed 

These benefits lead to a high point of self-perception and improved quality of life. Individuals are no longer embarrassed by wearing glasses or contact lenses or have to worry about an excuse not to wear their glasses or contact lenses.

Since LASIK surgery is considered a cosmetic procedure, it is covered by medical insurance in some cases. There are some restrictions on the amount that insurance will pay for, but many insurance companies are willing to provide coverage for the procedure if the patient has already been paying out-of-pocket for their previous eye prescription. LASIK surgery is also included in Medicare. 

Risks of LASIK surgery:

· Eye infection rarely occurs, with just over one percent of cases having an infection after the procedure. An infection can lead to scarring and swelling of the cornea, which can cause permanent vision loss. 

· The flap that is created by LASIK may be pulled back or sewn together incorrectly. If this happens during your LASIK surgery, it usually happens during the first two hours after the procedure has been performed. The poor result is not a complication that cannot be repaired, but it does require a second surgery for corrective measures. This has led to a complication rate of approximately 2 percent. 

· Dry eyes usually persist for 12 months after LASIK; although this is only a 50 percent increase over preoperative levels, it can be bothersome for some patients. Artificial tears are often used to relieve dry eye symptoms. 

· In rare cases, eyes heal poorly from the procedure and vision may not be as good as predicted by your doctor before surgery. As a result, additional surgery is required to improve the results of LASIK. The most severe risk of poor healing is inflammation at the flap edge, which may lead to scarring or poor healing of corneal tissue that can cause permanent loss of vision. Other risks of poor healing include infection, possibly due to improper excision of the flap. 

· The epithelium that is destroyed during the LASIK procedure may not heal well after surgery, resulting in a condition known as epithelial ingrowth. This condition can result in pain and eye redness. 

· Flap misalignment (sub-optimal refractive correction) is an uncommon complication; this occurs when the flap does not conform precisely to the topography of the cornea or misshapes at its leading edge. It is usually corrected during your follow-up visits 2–3 weeks and 6–8 weeks after surgery. 

· Decrease in night vision perception, which may be corrected with the addition of glasses or contact lenses.

 

Complications from LASIK are rare and do not occur with every patient. Some patients have even reported that permanent side effects from their surgeries have actually improved their quality of life. For example, patients with extreme myopia have suffered from severe eye fatigue due to having constant nearsightedness. After the procedure has been performed, these individuals experience no more eye fatigue and can now read for extended periods of time without experiencing painful headaches. These side effects go beyond dry eyes, but there are treatments to help relieve dry eyes and avoid dry eyes altogether if necessary. 

LASIK has become the most commonly performed type of refractive surgery in the United States. In 2010, LASIK was performed on over 780,000 eyes; by 2015, it had increased to over 900,000. In Europe and other parts of the world, the incidence is steadily increasing as well. This trend is expected to continue as more people become aware of this type of procedure and are able to afford access to it.

LASIK eye surgery cost:

In the United States, LASIK costs approximately $3,400 per eye at a price comparable to other ophthalmic surgical procedures. In Europe and Australia, the LASIK price may range from €2,000 to €6,000 per eye. Prices in Mexico range from approximately $1,100 to $1,600 per eye (USD).

There have been a number of research studies on the subject:

LASIK is used for correction of myopia in both children and adults. In children under 12 years old, LASIK can be performed successfully with a safety factor <1.0. In adults over 40, LASIK success depends on the patient's preoperative refractive error and quality of the patient's corneal tissue. 

Laser in situ keratomileusis (LASIK) is an outpatient procedure done under local anesthesia with mild sedation. The surgery is performed in a doctor's office and takes 20 minutes to 30 minutes per eye. The procedure can be done either with or without the use of a blade to create a flap in the cornea. A blade is used when the patient has thin corneas or highly myopic eyes that would be difficult to treat using other methods, such as topography guided treatment (TGT). 

For TGT, the topography of an individual's cornea is examined and mapped before surgery. Using a computerized device that feeds the doctor information on the flap thickness and placement, minor adjustments can be made to improve vision or correct astigmatism. During LASIK surgery, the laser creates a flap in the cornea by removing a part of it.

There are two basic types of LASIK:

One type of LASIK surgery is done with a special flap, called the “keratome”. The keratome has a blade with tiny teeth that is used to cut through the upper layer of the cornea. The flap is then replaced in its place. This type of procedure is sometimes used to correct astigmatism by removing a small piece of cornea, or when an irregular cornea can be fixed by removing a small chunk and leaving behind the rest of the correction.

"Rc-LASIK" surgery also uses a special cutting instrument to segment off some tissue from the top surface of the cornea so as to create a smooth semi-circular flap. 

Photorefractive keratectomy (PRK) is a low risk, non-invasive procedure that uses a refractive power of only 4 diopters. Acrysofaine is used as the excimer laser to reshape the cornea into its final shape. There are no stitches or skin incisions made during this procedure, and patients feel little pain or discomfort after the procedure. In contrast, TK (tissue-based) LASIK requires two significant surgery procedures. The first procedure uses an excimer laser to create a small flap in the cornea. The second procedure can be done with a blade, however it is more commonly done using an instrument called the microkeratome. After creating another flap in the cornea, a hinge is folded in and placed on top of the cornea to hold the flap in place. As opposed to TK LASIK, PRK does not require anesthesia and patients can go home on the same day as their procedure.

 

In both procedures, there is no tightening or suturing of muscles required; hence, it is less invasive than other types of surgery. PRK also has a shorter recovery period when compared to TK LASIK surgery. In addition, the patient's eyesight is fully functional after the procedure, unlike TK LASIK, which requires a 5-day recovery period.

The primary benefit of PRK surgery is that it does not require patients to get used to glasses or contacts again, which can lead some patients to still prefer LASIK surgery for cosmetic reasons. The body's natural healing processes will take care of all the complications associated with PRK.

Most studies indicate that PRK provides no more postoperative improvements in visual acuity than those of TK LASIK. In other words, both types of procedures have similar vision after surgery and there is no reason to choose one over the other. 

The visual results of the surgery are dependent on the type of procedure used, along with various other factors. The most common postoperative complaints after LASIK surgery include: 

LASIK and PRK are used to treat myopia and hyperopia. These procedures create a corneal flap, which can move forward (front-folds) and backward (back-folds). The surgeon uses instruments to measure the corneal thickness for flap creation. This is crucial for achieving the best possible outcome by performing either LASIK or PRK. If the excimer laser cannot be focused upon the stromal bed, the surgeon must adjust the flap thickness prior to treatment.

 

LASIK surgery can be performed with a technique that leaves the corneal flap in place (T-shaped, or torsional) – known as monovision LASIK – with the intention of obtaining only one prescription for each eye. For example, if someone has 20/20 vision before the surgery, after LASIK surgery one eye are achieve perfect distance vision (e.g., 20/20), and their other eye will have near-perfect vision (e.g., 20/30). Consequently, some patients may prefer to get one eye corrected for far-range vision and the other corrected for near-vision needs (one eye may require a +2.00 or +3.00 correction, and the other eye may require +1.00 or +2.00 correction). To obtain this with PRK, a patient must undergo three procedures, which is inconvenient and very expensive. Some patients are considering laser eye surgery as a more cost-effective option than fusing their eyes together in an attempt to correct astigmatism and get near perfect vision in both eyes (e.g., Zeiss Eye Surgical System).

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