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.

PURPOSE:
To review common complications noted with LASIK.

METHODS:
Review of personal experience of the author with the procedure and work published in the literature.

RESULTS:
The most common complications of the LASIK procedure include flap irregularities, epithelium and other materials within the lamellar interface, irregular astigmatism, regular astigmatism, regression, and overcorrection. Infections are a rare but potentially serious complication.

CONCLUSIONS:
LASIK has impressive potential for the correction of myopia and hyperopia. Surgeons who perform the procedure must be familiar with recognition and treatment of potential complications of LASIK.

HIS NOTE:
There are relatively few publications in peer-reviewed journals devoted to the complications of LASIK.

Flap abnormalities are the most feared of LASIK complications and have the potential for serious visual loss. They range from catastrophic to insignificant. In a recent study by Stulting et al. of 1,013 consecutive eyes that underwent LASIK, 2.7% had intraoperative flap complications. Another 4% of eyes in this study had postoperative flap complications.

The surgeon should mark the surface of the cornea for orientation before beginning the procedure, so he knows where to replace the flap.

Stop the whole procedure immediately if a bad or irregular flap cut occurs. Use a Soflens 66 F/M base curve lens on the eye for 3 days. Redo the LASIK in 3 months, and there should be no problem.

The most serious risk is human error in placing the plate-controlling depth of the cut. Newer microkeratomes, including the Chiron Hansatome, have a fixed depth plate, which will significantly reduce the incidence of serious LASIK complications.

Again, the Chiron Hansatome is the best device to use these days, NOT the ACS.

A thin or donut-shaped flap can occur if inadequate suction or loss of suction occurs during passage of the microkeratome head. In either case, the irregular flap should be returned to its original position without laser treatment. This is easily done if the surgeon marked the surface of the cornea for orientation before beginning the procedure. After about 3 months the procedure can be repeated in most cases. Dr. Wilson suggested using the pneumotonometer (Mentor Ophthalmics, Santa Barbara, CA), and the Chiron Hansatome, that automatically stops if suction is broken during passage of the microkeratome head.

He goes into more details about having to do no-touch PRK if problems develop in the lamellar surfaces, or for central corneal scars. It works best if the patient was 8-12 diopters to begin with.

Sometimes the cap will completely come off, so look for it; it may be in the microkeratome head assembly. Replace the cap using the orientation marks.

Postop flap misplacement can be more easily avoided if about five minute's duration is allowed for the flap to adhere to the bed. The central cornea should be kept moist and the periphery dry to facilitate adhesion to the bed.

To decrease risk of postop flap misplacement, use of a Soflens 66 (Bausch and Lomb) F/M base curve contact lens, without patching, on all eyes for the first 24 h after LASIK. This will prevent the eyelid from encountering the edge of the flap until the epithelium has closed.

The upper lid seems more likely to generate a flap displacement, so use of superior hinges may decrease this complications.

Flap wrinkling may occur during the procedure and may not be detectable with the operating microscope. Some surgeons inspect the flap at the slit lamp immediately after surgery to insure flap wrinkles are not present.

Sometimes the wrinkling is done by the patient rubbing the eye, perhaps while asleep. Every effort should be made to eliminate flap wrinkling or misalignment as soon as it is identified so that permanent irregular astigmatism can be prevented. The flap should be lifted, profusely irrigated and smoothed with strokes of a rounded spatula or a wet sponge. In some instances, it may be impossible to eliminate flap wrinkles. In these cases, it may be necessary to fit a gas-permeable contact lens to improve vision.

It is best to treat the wrinkling within one week postop.

Epithelial growth within the lamellar interface can produce significant morbidity (disease/problems) associated with LASIK. Some doctors seem to have more incidences of this problem than other doctors do. Dr. Wilson only had one incident in 200 LASIK procedures, and that was associated with a donut-shaped flap.

Reusing a blade for multiple flaps may increase the likelihood that this will occur since the blade will become dull. If cells are left between the surface, they may grow and nest there, or may continue to expand and may produce more significant complications. Sometimes the cells grow into the interface from the periphery, or from a donut-shaped flap.

To help prevent this situation, and prevent a reflux of tears, epithelial debris, and surface mucus from the fornix, irrigate the flap and bed with BSS (Balanced Salt Solution). Follow this by sweeping the bed and flap with lint-free sponges, starting from the center, and working outwards. Follow with another BSS irrigation.

The two common complications are that the growth may infringe on or cover the pupil. More commonly, however, the epithelium lifts the flap and produces irregular astigmatism.

For enhancements, do not use a spatula to break open the interface. It may be preferable to break the interface open with a probe, grasp the far edge of the flap with 0.12 forceps, and gently peel the flap back.

Treatment is that the flap should be lifted and the epithelium removed by scraping from the bed and flap with a scalpel or spatula, followed with BSS irrigation and cleaning with a sponge. If you have to do this more than two times, laser all over the flap, bed, and periphery to ensure it's all gone.

Other foreign materials may also be introduced beneath the flap during the LASIK procedure. These include mucus or oil from the tear film, metal shavings from the microkeratome blade, filaments from a sponge, lashes, and other foreign materials. Typically, if the materials are in the periphery and not associated with keratitis or corneal vascularization, they can be left.

Irregular astigmatisms and associated loss of best spectacle-corrected acuity are one of the most common complications of LASIK, including irregular flap cuts, flap misalignment, and epithelial growth within the interface.

The VisX is the best machine available to prevent it (4-99).

Following are other factors.

CENTRAL ISLANDS may be related to the higher correcteds (higher diopters) that are attempted with LASIK, where effluent debris redeposits in the center of the ablation. Water on the surface may increase the incidence of central islands, so combat this tendency by wiping the surface of the bed with a sponge every 40-50 bursts. The VisX laser has anti-island software. Central islands tend not to resolve spontaneously, thus they may be treated within a few months after the primary procedure. To a large extent, treatment of islands is an art. The doctor should be conservative in reapplying the laser.

DECENTRATION can result in severe irregular astigmatism overlying the entrance pupil and cause glare, monocular diplopia, and halo phenomenon. To some extent, this can be remedied by performing the ablation under the lowest illumination possible so that the patient can see the fixation target. Pupil tracking becomes very difficult once the flap is lifted. Correction is very difficult and again is more art than science. Until better treatments, the best is prophylactic and the surgeon should strive to insure that the primary ablation is centered overlying the entrance pupil.

Studies show... that 3% irregular astigmatism occurs after LASIK, loss of two or more lines of best spectacle-corrected visual acuity at one-year follow-up.

Irregular astigmatism may be the most significant complication that limits the efficacy and safety of LASIK. The best treatment is prevention. In some cases, a rigid gas-permeable contact lens must be fitted to restore vision. If the irregular astigmatism is associated with scarring, for example, with a small central irregular cap, a penetrating keratoplasty may be required to restore vision.

Astigmatism may be corneal or retinal, so do your eye surgery based on that.

Changes in regular astigmatism are common after LASIK. It is reduced when the Chiron Corneal Shaper is used to generate the flap with a nasal hinge. AK still has a role in correction of astigmatism after LASIK.

Our preference is to correct myopia with LASIK (and if necessary, LASIK enhancement) and then to use AK to correct residual astigmatism once there appears to be no future need to raise the flap.

The VisX is the best LASIK machine to use for astigmatism (4-99).

It had been thought there was no regression after LASIK. This followed from the erroneous belief that there was no wound healing associated with LASIK. Recent studies, however, conclusively demonstrated that wound healing does occur after LASIK.

Fortunately, regression following LASIK can be easily treated by lifting the flap and ablating with the excimer laser. Flaps have been successfully lifted as long as 18 months after primary LASIK. Some surgeons prefer to cut a new flap; this is easily done, but the risk of a flap complication must be considered. We have not resorted to cutting a new flap in >100 LASIK enhancements.

Nonsteroidal agents (NSAIDs) should probably be avoided when LASIK is performed because there is weak evidence that regression and interface haze may be associated with these medications.

Transepithelial PRK can be applied to correct a small amount of myopia in some cases, but care should be taken in generally applying this PRK enhancement method until more cases have been studied.

Overcorrection is disappointingly common after LASIK. A number of patients were referred with 1-3 D of overcorrection. The best treatment is prophylactic. Fortunately, many cases will have regression during the first year after surgery. Thus, the patient is best monitored for at least 6-12 months. Some cases, however, will be permanently overcorrected to clinically significant hyperopia.

Currently, treatment for these complications is sub-optimal. A number of eyes that had overcorrection after LASIK performed outside the United States had holmium-YAG laser treatment for hyperopia. The eyes that were treated with this technique and examined by the author had initial correction followed by instability and regression.

Probably the most promising modality is the use of hyperopic ablation beneath the flap. This treatment is not currently available in the United States but should be within the next year. Use of hyperopic ablation is facilitated by having a large flap (9.5 - 10.5 mm) unless there is significant peripheral pannus before surgery.

While awaiting spontaneous regression or FDA approval of hyperopic ablation, correction can be given with a soft contact lens, such as the Soflens 66 (Bausch and Lomb). This lens typically fits without decentration, bubbles beneath the lens, or other problems that are frequently seen with other soft contact lenses.

Is rare if appropriate precautions are taken. It is very important for the patient to apply fluoroquinilone antibiotic 4 times per day for 5-7 days after surgery.

If an infiltrate is noted, it should be treated as infectious until proven otherwise. Consultation with a cornea and external disease specialist is advised. Cultures are mandatory and should include tests for bacteria, fungus, and Acanthamoega. Initially, fortified antibiotics should be applied at least every hour around the clock until the infection is controlled. It may be necessary to retract the flap with sutures to gain sufficient penetration of the antibiotics in some cases.

Several surgeons reported lamellar keratitis after the LASIK procedure. In this condition, several infiltrates at the level of the lamellar interface may be noted. These cases have been responsive to topical corticosteroids. We speculate that epithelial debris that was not washed from the interface could trigger such a response in some eyes. This is a bad problem, and occurs 1-3 days after LASIK. The cause may be toxic substances on the microkeratome, using a new soap to clean the machine equipment, or materials of tears, debris, and cytokines.

LASIK is a procedure with the potential to correct low to high myopia and hyperopia safely with outstanding visual performance of the eye. Undoubtedly, improvements will be made in microkeratomes and lasers that will further decrease the incidence of complications after this procedure. Unfortunately, however, the LASIK surgeon will always need to be adept at handling an impressive array of complications that may occur with this procedure. Many of these complications are independent of the microkeratome or laser used in performing the procedure.

Dr. Wilson has done LASIK 3 years, and has performed over 1000 procedures.

Topographic screenings are very important, but are NOT perfectly reliable.

Do NOT wet the eye until after ablation or else it may change the laser effects (like the sunlight shining through glass to burn an ant).

Make your patient selection based on their personality, as you'll be "living" with the patient for a year or two.

Soft lens wearers may be able to have LASIK 2 weeks usually, or 3-6 weeks tops, after removal.

Rigid lens wearer's average time span before having LASIK is 3 months, but range from 1 to 12 months. Rigid lens wearers had more corneal abnormalities. They can wear soft lenses to replace their rigid to decrease the time until LASIK is performed.

Rigid lens wearers may NEVER have the quality of vision as with their lenses because the rigid gives the best vision results.

LASIK is NOT recommended for those who do extremely fine work, such as jewelry or watch repair.

Female hormones DO effect the eyes with pregnant and lactating women, but doctors are unsure why. (Note Dr. Zaidman mentions the same thing at the end of his article.)

After the lenses are removed to prepare for LASIK, eyes may change one diopter, so it's imporatant for the cornea to stabilize prior to surgery.

If the contact lens rides too high or low, it takes more time for the cornea to return to normal shape and stabilization (it took 8 months for some people).

Contact lenses may cause warpage of the cornea, structural changes, and cell death.

"Drying time" after doctors replaced the flap started at 5 minutes, then 3 minutes, and now some do 2 minutes.

He puts his postop patients STAT into a large soft lens for safety to keep the flap flat just the first night.

Keratoconus (a "drooping" of the cornea) rules out having LASIK. It occurs in 5.7% in contact lens wearers, and less than 1% without contact lenses.

A doctor can lift the flaps up to one year after LASIK.

LASIK and PRK enhancements can cause problems when suction is put on the eye.

LASIK surgery is like no other. At one extreme it calls on the otherwise normal and well trained physician/surgeon to be a highly technical computer and machine operator, while at the other an extremely patient, supportive but wise psychologist. There is no room for any error or variation in calculation or delivery of surgical technique, and the devotion to the patients support and comfort must be complete.

Performing the procedure is scary for new surgeons even if they are veterans of radial keratotomy and other anterior segment procedures. Adoption of this product line has been a daunting task for most opthalmology groups including my own. Acquisition of formally trained subspecialists to be leaders and teachers within our group continues to make the education and training process of others more sure and confident. In this way a second tier of intramurally recruited anterior segment surgeons can be trained so that they can also effectively and safely deliver the procedure.

Despite diligent educational and training efforts, early problems include: failure to consult with associates in difficult cases, misinterpretation of computerized videokeratography, inaccurate calculation, incomplete flap creation, decentration of the surgical bed, failure to dry bed as needed during laser application, early and late flap movement. Despite these difficulties, all cases accomplished by the subspecialists and second tier surgeons have been successful resulting in good vision in mostly happy patients. Long range planning is important to the successful implementation of the new surgery within the practice. Especially critical is the recruitment of additional surgeons and associated staff prior to undertaking delivery of the procedure.

When he did RK, he had an "enhancement" rate of 50%, but his enhancement rate for LASIK currently is only 4% (excellent news for his LASIK patients!).

Dr. Davison WAS doing enhancements by slipping a scapula under the flap, and pushing it back and forth and in and out around the edge to loosen it up. He learned during this meeting the best way to do enhancements is to grab the flap opposite the hinge, and gentle pull it back; it does so easily. While pushing a device back and forth under the flap, one can introduce bacteria, bugs, extra unnecessary cellular debris, etc. onto the site, which can cause future complications.

Doctors, remember, some people will heal differently than others. Be aware of it and expect it.

The most common complications he has are related to the hinge/flap.

Don't dry and wipe the cut eye more than once.

Moisten the eye before lasering. (Dr. Wilson said to dry the eye before lasering, or abnormal laser effects may occur.)

Refractive surgery is now a business, as it is elective surgery.

More and more eye docs are going into LASIK because it is so lucrative.

If the prices become too low, too many patients will want to be done, decreasing the quality of patient interaction and care.

One-fourth of his patients were referrals by other patients (very good sign).

This is a wonderful doctor! A really neat guy, truly personable, and fun. I'd let him do me anytime!

What's amazing about his presentation is that he showed videos of his first few LASIK procedures, and they were not successful. A couple times he did not cut the flap completely, and didn't know what to do, so he re-cut it again. (Now that he knows more, if that were to happen, he'll STOP IMMEDIATELY, clean what can be cleaned, and let the eye reheal before trying again.)

One other video showed that the skin of the patient getting caught in the moving gears of the keratome, so that was pinching the patient, and resulted in an incomplete flap.

He said to NEVER be the first or second or so patient of ANY doctor new to LASIK. Always go to the guy with the most successful experiences! And do not do relatives or friends.

Dr. Davidson is well experienced now. He runs the Wolfe Clinic in Iowa since 1994, and has almost 20 eye clinics in the area.

PURPOSE:
The purpose of this prospective study is to evaluate the corneal topography of patients who sought an opinion regarding refractive surgery for the correction of myopia.

METHODS:
Both eyes of 53 patients were evaluated with a topographic modeling system. Forty-two patients wore contact lenses (84 eyes: 36 rigid contact lenses and 48 soft contact lenses). Ten patients (20 eyes) wore glasses alone, and one patient (2 eyes) wore neither glasses nor contact lenses for correction of myopia.

RESULTS:
Thirty-five (33%) of 106 eyes were found to have abnormal corneal topography. Of the 42 patients (84 eyes) who wore contact lenses, 32 eyes (38%) had irregular astigmatism, loss of radial symmetry, or absence of the normal progressive flattening from the center to the periphery of the cornea, consistent with contact lens-induced corneal warpage. Alterations were more frequent and severe in rigid contact lens wearers. Three patients (5.7%) received a diagnosis of definite keratoconus, a higher incidence than has been reported in the general population. Topographic abnormalities in most, if not all, of the eyes would not have been detected by visual inspection of the photokeratoscopic images alone.

CONCLUSIONS:
Appropriate preoperative detection and management of corneal topographic abnormalities are essential steps in every refractive surgical procedure. The overall efficacy and safety of procedures such as radial keratotomy and photorefractive keratectomy likely will be improved once the unpredictable variables of contact lens-induced warpage and occult ectatic disease are eliminated by topographic screening before surgery. Patients with keratoconus may be over-represented in the refractive surgery population due to self-selection.

With some people, their rigid contact lens ride "low" or ride "high" on the eyeball, which changes the shape of the cornea.

38% of those who wore contact lenses had contact lens-induced corneal topographic abnormalities, especially with rigid lenses.

If the cornea appears normal immediately after taking out the lenses, the eyes should still be monitored for any potential future corneal changes, such as every two weeks, to confirm stability.

PMMA (16-rigid polymethylmethacrylate) contact lens wearers have a mean time of 15 weeks (range of 4 - 22 weeks) for the eyes to stabilize after removal for LASIK surgery.

Rigid contact lens wearers have a mean time of 10 weeks (range 4 - 21 weeks) for stabilization of eyes after removal.

"In our experience, topographic abnormalities are most severe in many rigid lens wearers at 2 to 4 weeks after removal of the lenses."

Soft contact lens wearers usually resolve faster, mean time 5 weeks (range 3-6 weeks).

LASIK should not be done on those with keratoconus.

Apoptosis is normal cell death after injury to the cells around the area.

It helps prevent the Herpes Simplex Virus from invading the eye area.

After LASIK and PRK, there is an initial reaction of keratocyic cell death, maximum at 4 hours post op.

There can be 5-10% regression related to keratocytic apoptosis.

It's VIP to clean the flap well during the procedure.

Some eyedrops may be helpful to prevent this apoptosis.

Trials are still on-going regarding the effects and treatment of apoptosis related to LASIK and PRK.

Further research needs to be done on this subject.

The eye is amazing! If the cornea is injured somehow, or susceptible to infection (such as to the herpes virus), a small layer of cells will grow to prevent the infection from spreading deeper into the eye tissue.

But this may become a problem after corneal surgery, because these extra cells may decrease the desired response of the surgery.

There are possibly some pharmacological means to prevent the apoptosis, but this is an all new research project.