corrective eye surgery

[Guest guest]

Since Lyssa had her eye surgery there has been lots of interest. I came

across these articles this a.m. The last is a " first hand account " . I

found it interesting, this has been a dream of mine for a long time. It is

very long so you might want to print it...

enjoy...

Cheryl

Laser Eye Surgery Comes of Age

, Medical Writer

It's one of the most popular medical procedures in the United States today.

According to a spokesman for the American Academy of Ophthalmology, over

800,000 Americans had laser vision correction surgery during 1999. Operations

to correct vision impairments have existed for decades. But the old

procedures involved physically shaving parts of the eye, which was a much

less precise and more hazardous operation. Now, through the use of lasers,

vision correction surgery has been transformed into a more routine procedure

with less recovery time and better results.

Laser vision correction surgery works by reshaping the cornea. The cornea is

the clear covering of the eyeball, which, among other jobs, is responsible

for most of the focusing of the light that enters the eye. According to Dr.

Barrie Soloway, co-director of Vision Correction at the New York Eye and Ear

Infirmary, it's helpful to think of the cornea the same way you would a

magnifying glass.

" It's strictly the shape of the cornea that accounts for its power, " says

Soloway. " Just like any magnifying glass--when you have a glass that's too

steep, it focuses very close--if it's very thick, so to speak. When a

magnifying glass is not quite as steep, it is more for distance. "

In a near-sighted person, the problem is that the cornea is too steep and

therefore too powerful. As a result, the near-sighted person can only see

objects in focus when they are close up. To fix this problem, surgeons use a

laser to flatten the cornea. Because the lasers are so precise, they can

vibrate targeted molecules in the center of the cornea, causing individual

hydrogen, carbon and oxygen molecules to fall off with each laser pulse.

According to Soloway, laser eye surgery works on the same premise as a more

common vision correction technique.

" If somebody uses contact lenses, [the cornea] is where they're putting the

contact lens on, " he says. " And [the surgery] is very similar to that in that

contact lenses provide a different shape to the front of the eye. And the

laser basically changes the shape of the front of the eye to be the

equivalent of what a contact lens would be. "

Lasers were more recently approved for surgery on far-sighted

individuals--these are people who generally do not need glasses early on, but

eventually need them for reading and distance. Soloway says this procedure is

slightly more difficult than surgery for near-sightedness.

" The problem primarily with far-sighted treatment, " he says, " is that the

laser needs to work on the peripheral part of the cornea or the edges to

steepen it basically. It removes tissue from the peripheral part in order to

create a steepness in the center. We can't add tissue or add cornea with

the... laser. "

A total of 100 million Americans wear prescriptions for visual disorders that

can be corrected with lasers.

The laser eye surgery itself lasts about 30 minutes. Most patients are able

to see well enough to walk immediately after the surgery and the majority are

able to drive by the next day.

A total of 100 million Americans wear prescriptions for visual disorders that

can be corrected with lasers. But Soloway warns that before patients rush to

their doctors demanding laser vision surgery, they need to realize that the

procedure is not perfect. " You do need patients to really understand that it

is surgery, " he says. " There are certain risks to surgery, even under the

best of all possible conditions. "

" We weed out patients that we don't think will end up with a good

result--people with a large pupil, people with a thin cornea. And again,

expectations do play a role. If somebody comes into my office, sits down and

says, 'I want to see 20/20 and I never ever want to wear glasses again,'

they're probably not going to be a great candidate. Their odds are that

they're gonna do well, but you certainly cannot guarantee that anybody is

going to see 20/20. "

Jan.2000

is a staff member of CBSHealthWatch by Medscape.

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PRK vs. Lasik Eye Surgery

Q: What is the difference between PRK laser eye surgery and LASIK surgery?

A: Photorefractive keratectomy (PRK) and laser-assisted in-situ

keratomileusis (LASIK) are both laser-assisted therapies intended to correct

near-sightedness (myopia). Both procedures can also correct a vision defect

called astigmatism. LASIK was also recently approved for correcting

far-sightedness (hyperopia). Both therapies use a special laser that produces

a narrow beam of invisible, ultraviolet light to remove tissue from the

cornea, the transparent circular part at the front of the eyeball. PRK uses

the laser to directly reshape and flatten the middle part of the cornea's

outer surface by removing microlayers of tissue. The flattened, reshaped

cornea allows light to focus more accurately on the retina, the

light-sensitive tissue at the back of the eye. PRK can be used on people with

up to 7 diopters of myopia. In clinical trials of this technique, most people

could see 20/40 or better (only slightly nearsighted), and about two-thirds

had perfect 20/20 vision after treatment. But it may take several months for

vision to clear completely and become stable.

LASIK is similar to PRK in that it reshapes and flattens central corneal

tissue. But in this technique, the surgeon makes an incision on the edge of

the cornea, creating a flap to split the cornea. The surgeon then removes

corneal tissue, just as with PRK, and then replaces the flap on the reshaped

cornea. The incision heals on its own and doesn't require stitches. LASIK is

approved for correcting up to 7 diopters of myopia, although the technique

has been tried on people with up to 12 diopters. Most people have 20/20

vision after the surgery, but repeat treatments are sometimes needed in

people with poor eyesight (more than 5-6 diopters). Just as with PRK, a

person's vision may take several months to clear completely. LASIK has both

advantages and disadvantages compared with PRK. It is generally less painful,

leads to generally sharper vision, and can treat more severe myopia. However,

because of the added step of creating a corneal flap, there are potential

additional complications relating to the flap.

If you are considering laser corrective eye surgery, ask your ophthalmologist

which procedure is best for you. .

This information, prepared by physicians at Beth Israel Deaconess Medical

Center (BIDMC), Harvard Medical School, is not medical advice and should not

replace consultation with your doctor. Staff at BIDMC provide Ask an Expert

responses to consumers for educational purposes only. Always consult your own

doctor about any opinions or recommendations with respect to your symptoms or

medical condition.

Jun.2000

Reviewed for medical accuracy by physicians at Beth Israel Deaconess Medical

Center (BIDMC), Harvard Medical School. BIDMC does not endorse any products

or services advertised on this Web site.

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I Can See Clearly Now

Glynna Prentice, Medical Writer

Laser eye surgery to correct vision, especially myopia (near-sightedness), is

an increasingly popular procedure. In May 1998, after 30 years of wearing

glasses, I decided to try it.

My glasses had always bothered me. Because I am severely myopic, the lenses

were thick and heavy, and I'd never been able to wear contact lenses

successfully. My eyes were too sensitive, my myopia too severe, for the

solutions available.

Then I heard about photorefractive keratotomy (PRK). The US Food and Drug

Administration had just (in March 1998) approved its use for those with

moderately severe myopia (between -7 and -12 diopters). Those of us in this

group had never had an option before. Would it work for me? I eagerly began

to research the topic.

The Options

In fact, I now had two options: PRK and a related procedure, laser in situ

keratomileusis (LASIK). (See the sidebar for details.)

The prospect of LASIK frankly appalled me. Cut open my eye? Not happening.

Epecially as the patient is awake during the procedure!

I visited several doctors to inquire about laser eye surgery, but basically

I'd already decided to have PRK. I felt I understood the risks and was ready

to face them. To protect myself, however, I bypassed the clinics with

promotional offers. I chose instead an ophthalmologist who consistently

participated in the clinical trials and who had performed hundreds of PRK and

LASIK procedures. An eye surgery was no time to economize.

The First Eye

My doctor advised that we do one eye at a time, beginning with my left.

Doctors calculate carefully how much tissue should be removed from the

cornea. But the more severe your myopia, the less precise the calculations

can be. In addition, each patient responds differently to the procedure,

further affecting the end result. My doctor felt it wiser to see how my first

eye responded before operating on the second.

The surgery lasted about 15 minutes, including preparation time. The laser

itself operated for only about a minute, stopping and starting as they

recalibrated it to correct my astigmatism. While the laser ran, I had to

stare fixedly at a red dot on the underside of the machine.

Time is relative. It was an extremely long, nerve-wracking minute. But when I

sat up after the procedure, my vision, previously so poor that I could barely

count my fingers at arm''s length, was now about 20/70. The next day (after

an extremely painful night), it was 20/40.

But the more severe your myopia, the less precise the calculations can be.

We expected the eye to continue to improve slightly, though not to 20/20. The

doctor had deliberately undercorrected, as this was my reading eye. Being

slightly nearsighted in the reading eye is one way to avoid needing bifocals.

And though I hadn't needed them yet, I was at the dangerous age when we begin

to lose visual acuity close up.

Now Farsighted?

The doctor was thrilled at the results, and so was I. But a week after the

surgery, I was slightly farsighted. The doctor frowned, and checked my eye.

No, his calculations were correct: He'd corrected precisely 8 diopters, and

the eye was healing beautifully.

At the next checkup, a week or 2 later, I was even more farsighted. I was

panicked. This was a disaster. The doctor waved it off and grunted, " Dry

eyes. " My eyes had become very dry since the surgery, and this was affecting

the healing. He told me to take lubricating eye drops every 4 hours.

A month after the surgery I was still farsighted in the operated eye, and the

dryness made it ache and itch madly. My doctor turned me over to his partner,

who strongly believed in treating dry eyes. We finally settled on using eye

drops constantly, and on plugging up the tear drainage ducts with temporary

collagen plugs. (I couldn't tolerate the permanent plugs.) This slowed down

tear loss and kept my eye lubricated.

Focusing Difficulty

And so things continued for 3 months. I visited the doctor almost weekly.

During this time I worried about how we'd operate on the second eye, which

was even more myopic. And I was also trying to hold down a job with two eyes

that simply wouldn't focus together.

I could use my left eye, now slightly farsighted, for negotiating the subway

and the city streets. Fortunately, living in New York, I didn't need to drive

a car to work, as that would have been impossible. But business trips were

out of the question.

And I was also trying to hold down a job with two eyes that simply wouldn't

focus together.

Office work was more difficult. For at least 2 of those 3 months, my left eye

could not bring print into focus. And for my right eye, severely myopic, I

needed my glasses for reading. In the end, I papered over the left lens of my

glasses so that I could focus with my right eye, and wore my glasses for

office work. It looked ridiculous, but it worked.

However, I'd never considered the possibility that recovery could take this

long. I'd estimated a week off work, at most--for both eyes. I'd certainly

never contemplated the daily impact it would have on my job.

The Second Eye

After 3 months my eye had finally stabilized exactly where it was supposed to

be. I was now slightly myopic, about 20/40, in my left eye. I also had some

residual astigmatism that made newsprint difficult to read when I was tired.

We were finally ready to operate on my second eye.

Given all the trouble I'd had, the doctor now recommended LASIK in the second

eye. I was terrified of LASIK, but I'd just endured 3 miserable months, and I

still had severe headaches when my left eye became dry. I said yes.

Even now, the concept of LASIK makes me squeamish. And you can't sleep

through it. As with PRK, you remain awake, eyes fixed on the red dot.

However, I barely noticed when the laser operated, as for me the worst--the

incision in the cornea--was already over by then.

And afterward my vision was nearly 20/20. I had very little pain, and my

recovery was rapid. For those who anticipate few complications, LASIK can

seem like immediate gratification: Walk in nearsighted, walk out perfect.

As with the first eye, however, I had to use eye drops to keep my eyes

lubricated. And in the months after the surgery, I did notice my vision

deteriorate. Six months after LASIK, I returned to my doctor for a touch-up

procedure.

This is relatively common with PRK, particularly for those with higher levels

of myopia, but it is rare for LASIK. According to my doctor, only about 2% of

LASIK patients require touch-ups due to vision that is stabilizing.

Again, the touch-up is a squeamish-making procedure, as the flap must be

lifted. But by now I was a hardened veteran. In for a penny, in for a pound,

I thought.

Would I Do It Again? Yes.

I was an unusual patient. I had many complications, which in the end called

for two different solutions. I am a textbook case of problems that can occur

with laser eye surgery.

But the surgeries themselves were also textbook perfect. A steady stream of

visiting doctors always clucked admiringly over my eyes whenever I had a

checkup. And in the end, despite the complications, my vision is almost

exactly what my doctor calculated it would be.

My effective vision in both eyes is now about 20/30. This is about what I was

able to achieve with glasses (I had not corrected to 20/20 for years). I have

good distance vision in the daytime, though I tend to have halos and some

haze at night. This is a common side effect of laser eye surgery.

I do not need glasses to read. And though I have trouble with very fine

print, I hope to avoid reading glasses for years to come.

I still have dry eyes, and I still use eye drops regularly, though much less

frequently than before. I occasionally get severe headaches, perhaps due to

dryness. I was told this would pass as the nerve endings heal. But it has now

been 18 months since the PRK, so I consider the headaches a permanent side

effect.

Would I still have laser eye surgery, knowing what I know now? Yes. I expect

I underestimated the risks, as do most people who have the procedure. I

certainly underestimated the recovery time and its effects on my personal and

professional life. And I never considered that there might be permanent side

effects.

But it is a joy to wake up and be able to see. For those of us who've lived

with poor vision, laser eye surgery can change our lives. It does not seem

like an elective procedure to us, but rather a medical necessity.

The Surgical Options in Detail

Both PRK and LASIK use a cold laser to vaporize tiny portions of the cornea

at the front of the eye. This flattens the cornea and, if necessary, can also

be used to even out irregularities that cause astigmatism. The goal is to

reduce the depth of the cornea so that light entering the eye will now focus

correctly on the retina, at the back of the eye.

In PRK, the laser vaporizes the exterior of the cornea. The procedure is

minimally invasive, and the laser is computer-controlled. However, because

the cornea's surface is scraped clean, the eye is extremely painful for the

first 18-24 hours after the procedure. And vision, while dramatically

improved immediately after surgery, may take weeks or even months to

stabilize.

In LASIK, the doctor first uses a knife-like instrument called a keratome to

slice open the cornea, creating a flap. The flap is peeled back, the

computer-controlled laser vaporizes the interior of the cornea, then the flap

is smoothed back into position. LASIK is a riskier procedure, since it

depends on the skill of the surgeon in cutting the flap. But it is relatively

painless because it affects the interior of the cornea, where there are no

nerve endings. And vision usually stabilizes immediately: You leave the

clinic with the vision you'll have

Advice for the day: If you have a lot of tension and you get a headache, do

what it says on the aspirin bottle: Take two and keep away from children.

[Guest guest]

Cheryl thanks for the info .. I was so thankful I had zippo complications,

now have 20/20 vision, never had any of the dry eye some talk about .. feels

totally normal!

lyssa