how does laser eye surgery improve vision?
Question:
Answers:
LASIK is used to cut thin flaps in the cornea and alter its shape thus improving ones vision.
The operation is performed with the patient awake and mobile; however, the patient typically is given a mild sedative (such as Valium or diazepam) and anesthetic eye drops. The surgeon operates the lasers, which make all of the incisions. A computer system tracks the patient's eye position 4,000 times per second, redirecting laser pulses for precise placement. A flap is cut in the cornea using a blade (called a microkeratome) or a femtosecond laser. A hinge is left at one end of this flap. The flap is folded back, revealing the stroma, the middle section of the cornea.
Then an excimer laser (193 nm) is used to remodel the corneal stroma. The laser vaporizes tissue in a finely controlled manner, without damaging adjacent stroma. The layers of tissue removed are tens of micrometers wide.
Other Answers:
I believe it reshapes the lens of your eyes..
It flattens out the cornea or lens of the eye so if you were nearsighted you have 20/20 vision afterwards.
Do a search on Lasik (laser surgury for the eye) complications and you will hear horror stories where people want to commit suicide after having it done because they see three or four or five multiples of everything like if there is a can of soup on the table they will see five cans of soup. There is no way to correct this and they would rather be blind it is so horrible.
Or they can't go out at night at all because the glare from headlights and other lights is like a knife peiercing their brains.
Or their tear ducts are damaged so that their eyes are always so dry that they have to put eyedrops in them eight times a day and get up every hour at night and do it.
It alters the shape of your lens so that the light passing through the lens focuses on the back of the eye (on the retina) more precisely allowing the brain to generate a crisp image.
Be warned though, there is a risk of long term damage to your vision through progressive scarring of your retina, which could with time impinge on your vision. For this reason very few opthamologists have the precedure perfomed. Very few are likely to either until there is at least 30 years of good data to draw upon to confirm it is safe in the long term.
Laser Eye Surgery
The surgery reshapes the cornea
The surgery is intended to reduce a person's dependency on glasses or contact lenses.
Doctors use a laser to permanently change the shape of the cornea, the clear covering over the coloured iris, and the lens, which is just behind the pupil of the eye.
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What does the surgery entail?
The surgery is done as an out-patient procedure and takes about an hour.
Local anaesthetic drops are placed in the eye being treated.
A knife is used to cut a flap in the cornea.
A hinge is left at one end of this flap.
The flap is folded back to reveal the middle part of the cornea. Pulses from a laser vaporise a portion of this and the flap is replaced.
An eye patch is usually worn over the treated eye for 24 hours.
How does this improve vision?
People need to wear glasses for different reasons. Some people are said to be short-sighted or myopic. This is due to the cornea being too steeply curved or the eye longer than normal.
Therefore, light rays fall in short of the retina - the area at the back of the eye that interprets the image - and results in blurred distance vision.
Other people are long-sighted or hyperopic because their cornea is too flat or the eye is too short. This means that the light rays focus too far beyond the retina.
Others have a condition where the cornea is oval shaped rather than spherical, called astigmatism. This produces two different focal points which can blur images at all distances.
Laser surgery to reshape the cornea can help to correct these problems.
Will it help with age-related vision loss?
No.
Laser surgery will not be able to cure age-related presbyopia and the need for reading glasses that people often develop in their mid-40's.
This is because presbyopia is not to do with a problem with the cornea. Instead, it occurs when the lens becoming less flexible with age.
Where can I get it?
Private treatment usually costs £1000-1500 per eye and is available at some NHS hospitals.
What are the risks?
Complications occur in less than 5% of cases, according to the Royal College of Ophthalmologists.
Some people have a problem with dry eyes in the months after surgery and artificial tear supplements might be needed in the long term.
Many patients have experienced glare or halo effects when night driving, particularly just after treatment. This is more likely the higher the correction that has been made, but is rarely severe.
In rare cases, excessive thinning of the eye wall can cause the shape of the eye to be unstable after treatment. Severe loss of vision is very unusual, but some patients could require corneal surgery or hard contact lenses to restore vision, it said.
Can both eyes be done on the same day?
Yes, but your consultant should outline the risks. In order to reduce the risk of cross contamination should complications arise, each eye should be treated as separate procedure.
How long will it take me to recover?
Most patients have a reasonably comfortable period after surgery and are back at work within a few days to a week.
Depending on the vision correction attempted, driving may be unsafe for one to two weeks. Tinted glasses with ultraviolet protection are needed when out in the sun for the first three months.
Source(s):
http://news.bbc.co.uk/2/hi/health/medical_notes/4649079.stm
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