Laser in-situ Keratomileusis is a procedure used to correct or reduce moderate to high levels of myopia (between -6 to -15.0 diopters or over +4.5 diopters). In LASIK, the surgeon combines the use of a keratome and the excimer laser to remove a thin layer of tissue from the center of the cornea. By removing the tissue, the central cornea is flattened and myopia is reduced.

First, the surgeon creates a 160 micrometers thick flap in the cornea using a surgical instrument called a microkeratome. Then he uses the laser to remove a micro-thin layer of tissue from the exposed corneal surface. Finally, the flap is replaced without the need for sutures. Usually the operated eye is protected with a contact lense for day or so.

My experience:

January 25, 1999:
Two days ago I was:
OD -11.75, -1.5
OS -12.00, -1.5


Yesterday I had lasik at TLC Manhattan with Dr. Fox...
Today I'm around 20/30 or so, and 20/20 if I douse my eyes with eye drops... the vision is there, just not the crispness. (I still have some surface irritation, so that's clouding things a bit.)
But ... I can see! Two days ago, I literally could not make out distinct objects beyond about 18 inches, today I walked around Manhattan without glasses and could see street signs from blocks away...
This is way more than I expected... I had been expecting at least a week or so to go by before I felt comfortable driving, and while due to the post-op glare I'm not going to try night driving yet, I'm certainly fine to drive during the day. (Two days ago, sitting in the car without glasses I couldn't see the steering wheel, much less the road.)

February 9, 1999:
My screen is back to 1024x768 and normal fonts, though it's a bit blurry still. Significant ghosting at night -- night driving is not pleasant on unfamiliar roads as signs are unreadable until 2-3 seconds away at 55mph.
Eye chart test says I'm 20/40 left, 20/80 right -- but that fluctuates every day. I am using Bion Tears every hour, and everything clears up quite a bit for a few minutes after putting those in. My Dr says that the surface of my cornea is extremely dry and not smooth and that is causing the blurriness. I'd have to say he's right, considering I can see nearly 20/20 for a few minutes after using eye drops. He says that as long as I keep using the drops for a few more weeks, the roughness will go away. My flaps were completely invisible by 1-week postop, with no wrinkles.

June 26, 1999:
Post-surgery:
OD plano, -0.50
OS plano, -1.00


Post-correction (same MD, 30 June 1999):
OD plano, 0
OS plano, 0


I've had serious problems with healing due to dry eye and my vision has been consistently cloudy. My co-manage eye doctor says my eyes are gunked up with sloughed-off epithelial cells. Dry-eye is made worse by my eyelids not closing all the way at night.

Although my eyes are technically zero sph/cyl, I get about 20/40 OD and 20/80 OS on the Snellen. Problems with photophobia since the June correction -- I need to wear sunglasses outside even in very overcast weather.

At no time since the original procedure in January has my vision been better than 20/40 for more than a day or two.

The dry-eye is treated with lots of drops (celluvisc) during the day, and Refresh PM at night with eyes taped shut. I've had significant improvement in the past week or so since I've started taping my eyes shut at night, but still no better than 20/40 or so.

My night vision is worse than 20/100.

December 28, 2000:
I wear glasses again. Thin ones, granted, and I don't always have to wear them -- in fact, sometimes I forget to put them on, and don't realize so until hours later...

... but wasn't the point of LASIK to not have to wear glasses?

I think the technology still has a ways to go before it's ready for primetime.

I still have absymal night vision.

April 2001:
If I could go back in time and undo my LASIK, I would.

June 2002:
No change in my opinion.

March 2004:
Still no change in my opinion.

October 2007:
Still no change in my opinion.

My Experience:

May 9, 2001

I'm a bit afraid. I've read dmd's wu above, and what if it happens to me? I'm only about 3 diopters down.

May 10, 2001

The big day. I go to Mass Eye and Ear Infimary, and, after jumping through the check-in hoops, go to the Morse Laser Center. The nurses are great - they offer to take custody of my convertible, since I won't be able to drive with the top down for a week or two.

They give me valium. It'll peak in six hours, but the operation is in one hour. I figure out later this is so I can go home and sleep it off.

The first eye is terrifying. I lie down on operating table, which will swing under the laser. They tape my eyelids out of the way, and then pin them in place with a monocle. A suction device drops onto the eye, and my vision goes black. I hear a whirring, sort of like a Lilliputian skilsaw.
My vision comes back, and I can see the opthamologist pull the cornea away. My vision goes all blurry, and I hear the technician say, "20 seconds." I hear a clicking for, you guessed it, 20 seconds. The cornea is folded back into place, and he starts moisturizing it with a small squeegee.

That's it. Twenty minutes later, he checks that eye, and then does the other. Twenty minutes after that, I'm free to go.

I can see. I don't have halos. No haze. My left eye isn't perfect - it's 20/30 - but my right eye is dead on.

May 11, 2001

I wake up in the middle of the night - I can see the clock that sits across the room - it's been twenty years since I could do that. I can see the stars, and the moon, and blades of grass. Dayenu - If I go back to being blind, this alone was worth it.

I saw the doc this morning - he says I can drive if I want to, so I do. I go to the Galleria and buy sunglasses - my first pair in a decade that don't have a prescription. As I walk in, I revel in the feel of wind against my eyelashes - I haven't felt that in ages. My vision is so sharp I want to cry with joy. Is this how everyone else sees the world?

May 12, 2001

My parents come down from Vermont today to make sure everything was all right. The four of us went to the Skywalk at the Prudential Center, and I went around and arouns watching all the people and things in Boston and Cambridge. (I could see people playing tennis at MIT!)

May 14, 2001

I'm back at work. I can make half the room queasy by describing the surgery, but a lot of folks are envious. Vision in my left eye seems to be improving, and the dryness in my right eye is lessening.

May 17, 2001

It's been one week since eye surgery. I have 20/20 vision in both eyes. I can see!

October 14, 2001

It's been 5 months, and I can still see fine. My eyes are drier than before, so I have to use eyedrops about once a day. No biggy. But I've discovered the joy of polarized sunglasses!

History

LASIK is the acronym for laser in situ keratomileusis, sometimes referred to as laser assisted in situ keratomileusis. The name refers the use of a laser to reshape the cornea without invading the adjacent cell layers. In situ is Greek for "in the natural or normal place." Medically, in situ means confined to the site of origin without invasion of neighboring tissues. Kerato is the Greek word for cornea and mileusis means "to shape."
Dr. Stephen Trokel published the first paper on laser assisted corrective surgery in 1983. In 1985, the first phototherapuetic karatectomy surgery was performed, and in 1987 the first photorefractive keratectomy (PRK) was performed, accidentally, on a blind patient by one Dr. McDonald. After performing trials on the patient, the patient's vision was miraculously restored to 20/20 and stayed there for years. In 1988, McDonald performed the first PRK on a patient with sight, during an FDA approved trial. Since then, the emphasis has changed from PRK to Lasik, which is very similar, even the laser is the same, except Lasik uses the laser to create a fold in the epithelium of the eye(mentioned several times above) in the eye, whereas in PKR, the laser is used to simply scrape off the epithelium. Both techniques are still in use today.


How well does Lasik perform versus various eye problems?

93% of patients with Myopia (near-sightedness) received 20/40 vision or better. 50% achieved 20/20 or better.

Patients with High myopia (really bad near-sightedness) experiences a higher incidence of regression and complications. Consult with physician.

Patients with Hyperopia (far-sightedness) will experience slightly more regression, but can expect basically the same results as those with Myopia.

Once again, people with High hyperopia can expect similar results to those with High myopia.


Possible Complications

Because the same basic Lasik procedure is used on all patients, those who heal faster or slower than the average may experience a slight over or under correction. Also, they may experience some regression because of changes in the shape of the cornea.

In about 1% of cases, DLK (Diffuse Lamellar Keratitis), a non-infectious inflammation under the cornea, may occur after 1 to 3 days. Doctors have several hypotheses, but are ultimately unsure of the causes. You will not feel the symptoms, and only a doctor will notice DLK. If caught early, DLK can be fixed easily and no vision-loss will occur. It is therefore imperative to keep up your scheduled visits to the doctor.

As was mentioned in some of the previous w/us, wrinkles can occur in the fold that is created by the procedure. Usually they cause no problems and can be ignored, but about 1 in 100 of patients experience one that causes a vision problem, and has to have it corrected. This wrinkling can be caused be rubbing your eyelid before the fold has a chance to fully reattach, poor positioning of the fold, and can also be caused by unknown causes. This occurs more frequently in patients with high myopia than other types.

Yet another complication can be caused by epithelial (skin) cells growing under the flap. This complication varies from doctor to doctor, so you should ask your doctor personally about the incidence he sees. One study reported a whopping 14% with this problem, while others may see only 3 or 4 in a thousand. Sometimes this complication doesn't need to be opperated on, but this isn't always the case. Doctors can prescribe eye drops to minimize the incidence of this happening.

Something that EVERY person who looks into Lasik should be aware of is that while your eye chart vision (ie 20/20, etc) may be much improved, you could very well experience a loss in contrast, night vision, and low-light sensitivity (dmd experienced this).

We have found two independent studies that note subjective reports of reduced night vision. First assessed 174 eyes that were treated between November 1997 and October 1998. Of them, 29% reported reduced night vision - however, it's important to note that 97% of patients indicated they would decided to have LASIK again.9 The second involved questionnaires sent to 50 patients; 8.8% reported difficulty with nighttime driving.10 Again, 98% noted overall satisfaction with their outcomes. The "Summary of Safety & Effectiveness Data" required by the US FDA tabulates the subjective reporting of glare, halos and difficulty with nighttime driving pre-operatively and post-operatively at various time intervals

Lastly, dry eyes after the opperation is a common occurence. 50% of people reported dry eyes at some part of the day 3 months after surgery. It has been noted by a few doctors that while other complications have been decreasing in frequency, dry eyes is increasing.

Technology

Lasik is done using an excimer laser, and the procedure itself has been described above. Two types of lasers are used, broad beam and scanning. Scanning is further subdivided into slit scanning and spot scanning. Most patients wouldn't notice a difference between any of the types. A description is provided by Dr. Stanley Teplick:
  • Broad beam Laser - A broad beam laser uses a relatively large beam diameter (from 6.0 to 8.0 millimeters) that can be manipulated to ablate the cornea. The broad-beam laser results in the shortest procedure time. This speed creates less likelihood of overcorrection and decentration — a complication caused by movement of the pupil. A disadvantage is an increased possibility of center islands — a complication related to ablation. However, ophthalmologists have learned to decrease the incidence of center islands by using several short laser pulses to ablate the cornea instead of one longer one.
  • Slit Scanning Lasers - A slit scanning laser uses relatively small beams linked to a rotational device with slit holes that can enlarge. During surgery, the laser beam scans across these holes to gradually increase the ablation zone. A uniform beam and potentially smoother ablations characterize slit scanning lasers. Disadvantages include a slightly higher propensity for decentration and slightly greater risk of overcorrection.
  • Spot Scanning Lasers - These systems have the potential to produce the smoothest ablations and use radar technology to track the eye's movement. They also have the potential to treat irregular astigmatism and link to topography. These lasers must be linked to eye tracking to ensure proper centration.

Finding the Right Doctor

Find out how many operations your doctor has performed, they really do get better over time. You will probably NOT want to go to a newbie doctor. Check to see the type of laser your doctor uses, some may use lasers not approved by the FDA, or even bought cheaply on the black market. This is important. Make sure your doctor is informative and courteous.

Conclusion

Remember that the doctors are messing with your eyes, the windows of the soul. Research every single thing you can find so you can make an informed decision. Don't be afraid to look around at different doctors, just because they do the same procedure does not mean that the results will always be the same. Be aware that even if the doctor does a perfectly fine job, things can still go wrong, complications beyond anyone's control can still occur, and you may still end up unsatisfied with your surgery. In the end, it's a decision you have to make.
Sources:
  • http://www.northdallaseye.com/lasikhistory.html
  • http://www.fda.gov/cdrh/LASIK/what.htm
  • http://www.lasikinstitute.org/technology.html

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