ABLATION: When the area is lasered; the act of lasering.

APOPTOSIS: Normal cell death due to aging, or to be replaced by healthier cells.

ASTIGMATISM: The refraction of a ray of light spreads over a diffuse area rather than being sharply focused on the retina. It's due to the differences in the curvature in various meridians of the cornea and lens of the eye. Causes the "halo" effect, I believe.

REGULAR ASTIGMATISM: Astigmatism that one has naturally.

IRREGULAR ASTIGMATISM: As a result of visual mechanical alteration.

BSS: Balanced Salt Solution, a solution that is similar to normal human eye water.

CYTOKINES: Not cells, but factors of them that occur when something happens to a cell.

ECTATIC: Capable of being stretched.

HYPEROPIA: Far-sightedness. Not a candidate for LASIK. Can be a bad result of over-correction via LASIK.

INTRAOPERATIVE: During the operation.

LAMELLAR: The cut area put back together. Like "layer".

KERARTITIS: Inflammation of the cornea.

KERATOCONUS: Conical protrusion of the center of the cornea without inflammation. In lay-woman's terms, it means the center of the cornea sags down, like a big beer belly does. NOT an indication for LASIK.

MEAN TIME: The number where half of the numbers are above it, and half are below it.

MICROKERATOME: The device used to slice the cornea before lasering away the excess cornea.

MONOCULAR DIPLOPIA: Seeing double out of one eye.

MYOPIA: Near-sightedness.

NONSTEROIDAL DRUGS: Same as NSAIDs: NonSteroidal Anti-Inflammatory Drugs: Aspirin, salicylates, fenoprofen, ibuprofen, naproxen, indomethacin, ketorolac, prioxicam (Feldene) and more.

OZ: Optic Zone, or the area of the cornea which is used directly for sight.

PACHYMETRY: The thickness of whatever it is you're talking about (for LASIK = cornea).

PANNUS: Newly formed superficial vascular tissue over the peripheral cornea. The area is cloudy, and its surface is uneven because it is covered with a film of new capillary blood vessels. It may cover the entire cornea.

PERIOPERATIVE: The period immediately before and after surgery, and during the surgery.

PMMA: (16-rigid polymethylmethacrylate); a type of rigid contact lens.

PRE-OP CONSIDERATIONS:
Corneal size: Normal is 11 to 11.5 mm
Small corneas protrude more through the suction ring yielding a larger flap.
Large corneas protrude less through the suction ring yielding a smaller flap.
Steep corneas yield a larger but thinner flap.
Flat corneas yield a smaller but thicker flap.
Thick corneas yield thicker flaps.
Thin corneas yield thinner flaps.
Thin and steep, plus ACS microkeratome could produce a very thin or perforated flap, therefore, have different microkeratomes available to accommodate different situations.
When treating myopia, calculate pre-op not to produce corneas flatter than 36.00 to avoid irregular astigmatism.
Calculate your pre-op pachymetry and remember that 250 microns of untouched corneal bed is not the only parameter for a happy ending.
OZ (optical zone), pupil diameter and amount of ablation are of paramount importance.
Will do LASIK when patient out of soft contacts in two weeks.
Will do LASIK when patient out of hard contacts in three weeks.

TRANS-OP CONSIDERATIONS:
I demand a new blade for each case, and I keep the registration number of the blade in my chart.
I drape lashes and use a peri-limbal sponge in some cases.
Learn to recognize ring suction failures: Use your finger to note the eye pressure, and the tonometer.
Mark, mark, mark before microkeratome passes.
I irrigate interface in some cases and I don't in others. I will continue to do the same.
I used to be furious about interface debris, I am more furious about it now.
None of my laser microscopes' lights make me happy; I'm trying to find a light source to find the debris before I send the patient out.
Debris does not disappear with time.
Use your better judgement to lift or not to lift, depending on the patient, the debris and your mood.
Flap folds don't disappear with time; iron them immediately.

POST-OP CONSIDERATIONS:
I examine my patients before leaving the clinic and later in my office the same day.
If there is any staining by day three, suspect a dry cornea, or worse, you could have epithelial in-growth.
When to re-treat and how much, remains the artistic paradigm.

Purpose or background:
To identify complications, separate them in microkeratome related, laser related, patient related and surgeon related and offer recommendations on prevention and management.

Methods:
First 500 cases (Jan. 1996 to Oct. 1997) performed by one surgeon (EZ), were reviewed for incidence of peri-operative and post-operative complications.

Results:
There were 21 cases or 11.85% intra-operative complications, including: free caps, loss of suction, incomplete passes, cap displacement, over-correction, under-correction, interface keratitis, ectasia and epithelial in-growth.

Under-corrections were all due to surgeon shyness, when I was learning my algorithm results.

Incomplete flap in one eye, and loss of suction in two eyes, occurred in the first weeks of doing LASIK, therefore I consider that a learning curve-related incident. Careful ring positioning and checking for proper IOP (interocular pressure) elevation is a must.

A free cap in one patient was due to failing to use the right size suction ring for a small flat cornea.

Cap displacement can be prevented by marking and realigning carefully.

Epithelial in-growth occurred in one eye on a patient that had a thin flap and kept staining with fluorescein in a small area at the entrance of the flap. I recommend, when staining occurs after the first week any place in the cornea, epithelial in-growth should be suspected.

Microkeratome related complications resulted in one thin flap, and interface keratitis in four eyes.

Thin flaps have been reported due to faulty blade, poor suction, and in my case, I believe this was due for failing to choose the right ring for the size and K's of the cornea.

Interface keratitis in four eyes of my cases have been described to have multi-factorial etiology. The etiology was recognized after a very careful investigation to the use of resterilized blades, without my knowledge.

CONCLUSIONS:

106 eyes or 60% of my patients gained lines of vision after LASIK.
159 eyes or 90% ended 20/40 or better.
Nevertheless 70 eyes or 34% lost lines of vision,
And 17 eyes or 10% ended 20/50 or worse. This remains a challenge.

All under-corrections were surgeon related.

All over-corrections were laser related. I recommend learning how to calibrate your laser and knowing the speed at which your laser should ablate.

Surgeon related complications occurred the first weeks of doing LASIK, these were all learning curve related.

Choosing the right suction ring and making sure the IOP elevates properly is most important.

Marking before doing the flap will prevent misalignment.

Strong recommendation of leaving 250 plus microns of untouched corneal bed is mandatory to avoid ectasia.

Microkeratome related complications should not happen. We should demand strict quality control and expect 100% honesty and efficiency from our surgical team.

Complications can be avoided in the pre-op period with careful examination. A good refraction is still, in this high tech scenario, the most important part of the equation.

Abort the procedure if you cannot get proper suction after the second try.

20/50 or worse is undesirable.

Does not favor monovision.

The hardest question of the LASIK surgeon is when to retreat.

Age factors, same refraction on different age groups, male or female, and specifically women over fifty who are being treated with estrogens, react very differently than other patients. One must be aware and inquire before surgery as to the hormonal balance of such patients. Recent birth control use or discontinuance may alter results.

Topography is not very useful after LASIK, especially to check on astigmatism.

Some LASIK doctors are not good at treatment of side effects of LASIK.

"Ghosting": Pupil focuses on center vision, and the periphry focuses on outer vision.

Pupil size DOES matter. One can have 20/20 vision and have ghosting, too.

ICS rings cause problems with peripheral vision.

PRK does not cause the dry eye side effect that LASIK has.

"Rare side effects aren't rare if they happen to you."

Because LASIK is so popular and mostly successful, problems are unusual, and there are doctors that may not know what to do about them.

Blindness can occur from the ACS keratome because the plate was not put in.

The suction device should not be put on more than a few times, or you can lacerate the iris.

Later trauma after LASIK can and DOES happen! For example, he described a case of someone bending down and getting poked in the eye by a cactus thorn. Treat all pokes of vegetation matter with anti-fungal drugs.

Bacterial keratitis is rare. It causes increased photophobia about four days post-op, and inflammation. Treat by lifting the flap, culturing the cells, irrigate, and treat with 30% sulfa.

Steroid drug use changes the effects of LASIK and vision.

Sands of Sahara occurred with a patient after he had an enhancement. He had hazy vision. There were many folds radiating centrally. He needed to have a corneal transplant, the patient is now happy.

Don't do family and friends!

The Mayo Clinic in Minnesota has done LASIK and PRK since August 1998.

Animal wounds heal differently than human wounds.