LASIK and Advanced Surface Ablation

LASIK and Advanced Surface Ablation by Hampton Roy, M.D.

2005-10-03T20:55:00.000-07:00

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Chapter 7- Dry Eyes and Refractive Surgery

2005-10-04T04:03:00.000-07:00

Dry eyes are very common after LASIK and Advanced Surface Ablation. In a normal eye this can occur for about two months following surgery. For an eye already dry before surgery, treatment must be undertaken to help the dry eyes situation. The following is a discussion of the causes and treatment of dry eyes.

CAUSES

1. EVAPORATION —omit air blowing across your eyes from a ceiling fan or CPAP machine.

2. HUMIDITY —humidify the air with a room humidifier. Heaters are also a cause of dry eyes.

3. BLINK RATE —if you blink less, your eyes may bother you more, as when using the computer.

4. MEDICATIONS —medicines for allergy, sinus, stomach, bladder, depression, high blood pressure, hormone supplements (Premarin, Estrogen) and oral contraceptives (birth control) can reduce tear production.

TREATMENTS

DRY EYES

1. DROPS —over the counter preservative free drops, such as GenTeal, Systane, Tears Again or Refresh Endura. Use one drop as frequently as needed during the day when the eye is dry.

2. OINTMENTS and GEL —over the counter preservative free preparations, such as GenTeal Gel or Tears Again gel at bedtime to lubricate the eye when asleep.

3. THERATEARS NUTRITION —a capsule of flax seed oil, vitamin E, and fish oil. 120 capsules cost $13.00/month at Walgreen’s, Target, K-Mart, Eckard Drug, Wal-Mart and others. Dosage is four capsules every morning.

4. PUNCTUM CLOSURE —each eyelid has two openings to the nose, one above and one below. Most of the tears exit through the lower punctum. A temporary lower lid plug lasts for several weeks. If this is beneficial, permanent closure can be completed with a cautery in the office.

5. Restasis 0.5% (cyclosporine ophthalmic drops) --Stimulates the lacrimal (tear) gland and oil glands of the lids. It is used twice a day and may take one to two months to see results. This medicine is used with severe, chronic, symptomatic dry eye without relief. The cost is $50.00 per month.

INFECTIONS

1. LID SCRUBS —removes the oil and bacteria from the lid margins.

2. DOXYCYCLINE —an antibiotic used with eyelid infections such as meibomianitis. Dosage is 50 mg twice a day for 14 days.

3. ANTIBIOTICS —such as Zymar (gatifloxacin) or Vigamox (moxifloxacin) for eye infections.

ALLERGIES

1. NON-STEROIDAL DROPS —can be used such as, Alocril (nedocromil sodium ophthalmic solution) , Zaditor (ketotifen fumarate ophthalmic solution) , Patanol (olopatadine hydrochloride ophthalmic solution) , or Elestat ( epinastine HCI ophthalmic solution). The symptoms are usually itching and may be accompanied by conjunctival edema and papillary conjunctivitis.

2. STEROID DROPS —these drops can cause glaucoma, cataracts, and enhance infections of the eye. Low-dosage with infrequent usage can be valuable in treatment of dry eye associated with allergy. Such eye drops are Alrex (loteprednol), Vexol (Rimexolone Ophthalmic Suspension) , or FML (fluorometholone) .

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Chapter 4- Complications of Advanced Surface Ablation

2005-10-04T03:17:00.000-07:00

1. Haze of the cornea can occur after Advanced Surface Ablation. It occurs more in higher levels of nearsightedness (over -8.00 diopters). With nearsightedness over -8.00 diopters, treatment with Mitomycin C is advised. This is applied for 2 minutes on the cornea with a sponge after the laser treatment. The eye is then irrigated. Another method to avoid haze is to cool the contact lens and drops used, in ice. Cold solutions and cold drops help avoid haze.

2. Infection is always a concern following eye surgery. Zymar (Gatifloxacin), a potent 4^th generation fluoroquinolone antibiotic is used 2 days before surgery and until the contact lens is removed. The eyelid is scrubbed with Betadine preoperatively to kill bacteria.

3. The epithelium may not heal down properly. This frequently is due to dry eyes. Dry eye treatment consists of providing extra moisture for the eye. If dry eye is recognized before laser treatment, dry eye treatment is carried out. (See dry-eye chapter 7)

4. The treatment ablation may be decentered. This condition can occur with both LASIK and Advanced Surface Ablation. The newer Excimer lasers have pupil trackers which align the center of the pupil during the treatment. This complication should be a complication of the past. With wavescan treatment parameters, decentered ablations can be treated with the newer algorithms.

5. The incidence of night glare and halos are reduced with the newer Excimer lasers treatments, whose treatment zones extend to 8 mm. Some patients with a pupil size in the dark of eight or more millimeters are not good candidates for laser surgery.

References

Buratto,L. and Brint, S.: Custom LASIK: Surgical Techniques and Complications. Thorofare, N.J.Slack. 2003 p161-287. [book]

Linebarger EJ, Hardten DR, Lindstrom RL. Diffuse lamellar keratitis: diagnosis and management. J. Cataract Refract Surg. 2000; 26: 1072-1077. [pubmed]

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Chapter 2- Complications of LASIK Surgery

2005-10-04T02:52:00.000-07:00

This will not be a complete discussion of all complications of LASIK or their management.

Thin corneal flaps and button holes- this complication is most often caused by inadequate microkeratome suction, poor microkeratome blade quality, steep cornea or microkeratome malfunction. The best treatment is to stop the procedure, replace the flap and in three to four months perform a new keratectomy using a thicker plate.
Free corneal flap- the cornea is completely cut off, rather than a hinge being present. The cornea is replaced after the laser treatment and the cornea is air-dried to allow it to stick. The lids are taped shut and the patient is examined the next day.
Flap displacement- sometimes after LASIK surgery in an accident or forcible rubbing of the eye, the flap can displace. There are no blood vessels in the flap so as long as three years following LASIK, flap displacement can occur.
Recurrent epithelial ingrowth – the top layer of the cornea (epithelium) may grow under the flap. Usually it is self-limited but can grow under the flap into the pupil. If the epithelial ingrowth disturbs vision, the flap can be lifted and the epithelial cells removed. This condition can reoccur.
Microbial keratitis- an infection under the corneal flap is rare. Factors such as lid infections, history of herpes of the eye, and long-term steroids on the eye can increase the risk of the infection. The infections can be bacterial or fungal. Prevention is the best avenue with meticulous sterile surgical technique. Treatment is with a variety of topical fortified antibiotics.
Corneal melting. The flap can melt with systemic diseases as rheumatoid arthritis or if local disorders of the cornea are present. Steroids, corneal lubricants and a contact lens can help the corneal surface heal.
Diffuse lamellar keratitis (DLK)- an unusual inflammation between the flap and cornea. The causes are multiple including debri under the flap and bacterial endotoxins. The treatment consists, in the early stages, of frequent topical corticosteroids. Later, the flap is lifted and treatment with steroids and antibiotics are used.
Decentered ablations- the treatment area not being centered can occur in LASIK and Advanced Surface Ablation. The newer Excimer lasers have trackers which help to center the pupil and keep it aligned during the treatment. This complication should be a complication of the past. With wavescan treatment parameters, decentered ablations can be treated with the newer algorithms.
Corneal ectasia- thinning of the cornea can occur weeks, months or years after the corneal treatment. The causes of this complication are hard to delineate. One factor may be the residual stromal thickness. After treatment the bed thickness needs to be at least 250 to 300 microns thick. Many surgeons will not operate on a cornea less than 500 microns. Some surgeons utilize Advanced Surface Ablation to prevent corneal ectasia.
Night glare and halos- Night glare and halos have been reduced with the newer Excimer lasers whose treatment zone extends to 8 mm. Some patients with a pupil size in the dark of eight or more millimeters are not good candidates for laser surgery.

Reference

Buratto,L. and Brint, S.: Custom LASIK: Surgical Techniques and Complications. Thorofare, N.J.Slack. 2003 p161-287. [book]

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Chapter 11- Options for Presbyopia

2005-10-04T04:50:00.000-07:00

Presbyopia is a condition in which the lens inside the eye can not change power and allow the person to see well at near. This usually occurs in individuals over the age of 40.

There are several options for the treatment of presbyopia, and they are as follows:

Glasses-

If you see well at distance you can use readers for close. You could use glasses that are bifocals with the distance lens not having any power and the near lens having the power.
If you need glasses for distance, you could have one pair for distance and a second pair for near. Another option is to wear one pair of glasses that are bifocal with a distance and near correction.

Contact lens-

You could wear contacts for the full distance correction and wear readers for near
You could wear a full distance correction for the dominant distance eye and wear a near correction on the non-dominant eye,
You could wear a multifocal contact that corrects for both distance and near.

Excimer laser refractive surgery-

You could be treated for the full distance correction and wear readers for near
You could have a full distance correction for the dominant distance eye and a near correction on the non-dominant near eye.

Intraocular lens- the crystalline lens just behind the pupil can be removed and a plastic lens replacement can be put into the eye.

The lens correction could be set both eyes for distance and wear readers for near.
One eye could be set distance (dominant eye) and the other eye for near (non-dominant eye)
There are three styles of lens implants that allow the person to see distance and near from each eye and are currently approved for use in the U.S. Your doctor will need to discuss with you the issues of multifocal lenses, such as halo and glare. In addition, your doctor will need to discuss the issues of infection, inflammation, retinal detachment and secondary membrane related to the operation of lens removal and intraocular lens placement. This surgery is similar to cataract surgery.

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LASIK and Advanced Surface Ablation

2005-10-03T21:10:00.000-07:00

Hampton Roy, M.D.

Little Rock, Arkansas

Published and distributed by MedRounds Publications, Inc.All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Published in The United States of America.

DISCLAIMER

The following material is intended for licensed physicians trained to practice medicine. The practice of medicine has associated risks and complications. The Authors and MedRounds Publications, Inc. do not intend for this material to replace proper medical and surgical training, and we shall not be liable to any user of our materials or any third person as a result of use of our educational materials.

Although the published material has been reviewed by licensed physicians for accuracy at the time of publication, medicine and the standard of care may change quickly. Physicians are reminded, therefore, that guidelines for care can change and opinions can be controversial. Neither MedRounds Publications, Inc., the sponsors nor contributing institutions, nor the individual authors and editors are responsible for deletions or inaccuracies in information or for claims of injury resulting from any such deletions or inaccuracies. We advise physicians to consult the primary research literature before implementing any new treatments.

The author has no financial interests in the commerical products discussed in this publication.

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2005-10-03T21:25:00.000-07:00

WHAT IS LASIK

COMPLICATIONS OF LASIK

WHAT IS ADVANCED SURFACE ABLATION

COMPLICATIONS OF ADVANCED SURFACE ABLATION

REFRACTIVE WORKUP AND OTHER OPTIONS

POST OPERATIVE CARE AND PAIN MANAGEMENT WITH LASIK AND ADVANCED SURFACE ABLATION

DRY EYES AND REFRACTIVE SURGERY

ENHANCEMENTS AFTER PREVIOUS REFRACTIVE SURGERY

WAVESCAN WITH AVAILABLE EXCIMER LASER

SURGICAL OUTCOMES

OPTIONS FOR PRESBYOPIA

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Chapter 10- Surgical Outcomes

2005-10-04T04:40:00.000-07:00

SURGICAL OUTCOMES USING WAVESCAN ANAYSIS

Nearsightedness- up to -6.00 diopters

98% of eyes are 20/20 or better with one laser treatment .
From -6.25 to-10.00 diopters, 95% of eyes are 20/20 or better.
This assumes the goal is for distance

Farsightedness- up to +4.00 diopters

90% of the eyes are 20/20 or better.
This assumes the goal is for distance.

Reference

Buratto,L. and Brint, S.: Custom LASIK: Surgical Techniques and Complications. Thorofare, N.J.Slack. 2003 p161-287. [book]

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Chapter 9- Wavescan and Excimer Lasers

2005-10-04T04:33:00.000-07:00

WAVESCAN WITH AVAILABLE EXCIMER LASERS

This discussion is limited to Excimer lasers that use wavescan to determine the treatment. Wavescan provides the best treatment. These four systems also have a pupil tracker for accuracy.

Visx is an American company that has been operational since the 1980’s. They have continued to upgrade and add innovations throughout its existence. This is my preference for Excimer laser.
Alcon LADARVision- The literature reports by capable surgeons demonstrate that this instrument and its wavescan component deliver a superb treatment.
Bausch and Lomb Zyoptix system- This system provides a wavescan analysis and Excimer laser. The literature reports that this laser system provides excellent results.
Asclepion- Meditec- This is a fine laser system that I used on a trip to India. The superb results are equal to the other three lasers with wavescan treatment previously discussed.

References

Awwad ST, El-Kateb M, Bowman RS et al. Wavefront-guided laser in situ keratomileusis with the Alcon CustomCornea and the VISX CustomVue: three-month results. J Refract Surg. 2004 Sep-Oct;20(5):S606-13. [pubmed]

Buratto,L. and Brint, S.: Custom LASIK: Surgical Techniques and Complications. Thorofare, N.J.Slack. 2003 p151-158 and 515-520 and 621-625. [book]

Durrie DS, Stahl J. Randomized comparison of custom laser in situ keratomileusis with the Alcon CustomCornea and the Bausch & Lomb Zyoptix systems: one-month results.
J Refract Surg. 2004 Sep-Oct;20(5):S614-8 [pubmed]

McDonald MB, Carr JD, Frantz JM et al. Laser in situ keratomileusis for myopia up to -11 with up to -5 diopters of astigmatism with the summit autonomous LADARVision Excimer laser system. Ophthalmology. 2001; 108: 309-316. [pubmed]

Panangopoulou SI, Pallikaris IG. Wavefront customized ablations with the WASCA Asclepion workstation. J Refract Surg. 17: S608-612,2001. [pubmed]

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Chapter 8- LASER TREATMENT AFTER PREVIOUS SURGERY AND SPECIAL CASES

2005-10-04T04:20:00.000-07:00

Previous laser surgery as photorefractive keratectomy (PRK) or LASIK- My preference is to treat on the surface rather than dealing with a LASIK flap. Some other surgeons deal with the LASIK flap. I use a wavescan “fingerprint” of the eye to determine the Advanced Surface Ablation custom treatment.
Previous refractive incisional surgery such as radial keratotomy (RK) or astigmatic keratotomy (AK). I prefer to get a wavescan “fingerprint” and treat as a custom treatment of Advanced Surface Ablation.
Corneal transplant- I prefer a wavescan to identify all the abnormalities and use this “fingerprint” as the treatment plan. More than one treatment may be needed. Some surgeons prefer to cut a LASIK flap.
Previous cataract surgery with or without an intraocular lens. I prefer a wavescan to identify all the abnormalities and use this “fingerprint” as the treatment plan. More than one treatment may be needed. Some surgeons prefer to cut a LASIK flap.
After previous surgery for glaucoma, retinal detachment or other non-refractive conditions. I prefer a wavescan to identify all the abnormalities and use this “fingerprint” as the treatment plan. Some surgeons prefer to cut a LASIK flap.
Nystagmus is a to and fro movement of the eyes. If the best corrected vision with glasses is 20/100 before surgery with glasses or contact lenses, than the best vision after refractive surgery will be 20/100 but without correction. Because of the constant movement, nystagmus is more difficult to get an accurate wavescan and provide an accurate treatment.
Dry eyes- with severe dry eyes, the patient needs to be aggressively treated before the refractive laser surgery. Dry eyes are to be expected for several months following surgery.
Decentered pupils- with the Visx Excimer laser, the surgeon sees a white light where the patient fixates. The automated eye tracker usually does not work well with decentered pupils and is turned off. The surgeon centers the laser on the light directed visual axis.

References

Davis, EA et al (eds): Refractive Surgery. Philadelphia, Lippincott Williams & Wilkins, Int. Ophthalmol Clin. 2000; 40(3): 111-123.

Forseto AS, Francesconi CM, Nose RA, Nose W. Laser in situ keratomileusis to correct refractive errors after keratoplasty. J. Cataract Refract Surg. 1999; 25:479-485. [pubmed]

Guell JL, Gris O, deMuller A, Corcostegui B. LASIK for the correction of residual refractive errors from previous surgical procedures. Ophthalmic Surg lasers. 1999; 30: 341-349. [pubmed]

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Chapter 6- Post-Operative Pain Management

2005-10-04T03:56:00.000-07:00

POST-OPERATIVE CARE AND PAIN MANAGEMENT WITH

LASIK AND ADVANCED SURFACE ABLATION

Post-operative care

I use an antibiotic, Zymar (gatifloxacin), four times a day for 2 days before surgery and then four times a day until the contact lens is removed.
I use a non-steroidal anti-inflammatory drop, Acular LS (ketorolac tromethamine ophthalmic solution) for the four days that the contact lens is on the eye after surgery.
I use a steroid drop, Pred Forte (prednisolone acetate) for two weeks, starting the day of surgery.
I recommend no eye make-up for one week following the surgery. When the patient resumes the use of makeup it should be new (especially mascara).
I recommend that the patient avoid getting water or shampoo in the eye for four days.

Pain management

I recommend that a small bag of crushed ice or frozen vegetables be used on the lids to reduce pain and swelling.
I prescribe Mepergan Forte (meperidine hydrochloride) for pain management. I recommend it be used frequently for the first 24 hours to reduce pain and allow the patient to sleep.
I recommend that the patient try to sleep as much as possible for the first 24 hours following surgery.
I furnish a Refresh Tears with a dilute anesthetic added to be used the initial 24 hours following surgery as often as necessary to reduce pain. It must be stopped after 24 hours or it will delay healing.

Reference

Buratto,L. and Brint, S.: Custom LASIK: Surgical Techniques and Complications. Thorofare, N.J.Slack. 2003. p 294-300. [book]

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Chapter 5- Pre-operative Workup Part II

2005-10-04T03:47:00.000-07:00

The following conditions should be evaluated (continued).

Contact lenses should be removed for at least 2 weeks before laser surgery. If the contact is a gas permeable or toric lens, they must not be worn for at least three weeks before laser surgery. Time out of contacts is necessary to acquire accurate correction measurements for the Excimer laser.
Dry eyes almost always occur following laser surgery, and last for two to three months. If there is a pre-existing dry eye condition, treatment should begin before the laser surgery.
Keratoconus is a thining of the central cornea. This condition can be diagnosed with pachymetry and topography. If the patient is a keratoconus suspect, Excimer laser is contraindicated. Other options are available.
Nearsightedness can be corrected with the Excimer laser in patients with up to 10 diopters of nearsightedness. If the patient has more than 10 diopters of nearsightedness, other options such as a refractive lens exchange should be considered. A refractive lens exchange involves removing the crystalline lens of the eye and replacing it with an intraocular lens.
Farsightedness can be corrected with the Excimer laser in patients with up to 4 diopters of farsightedness. If the patient has more than 4 diopters of farsightedness, other options such as a refractive lens exchange should be considered. A refractive lens exchange involves removing the crystalline lens of the eye and replacing it with an intraocular lens.
Astigmatism can be corrected with the Excimer laser in patients with up to 4 diopters of astigmatism.
Presbyopia is the loss of accommodation which prevents individuals from seeing well up close after the age of 40-42. The person who has a full distance correction may have difficulty with close vision. However, a person who is nearsighted may remove their glasses and see better. There are several options for correcting presbyopia. The first option is to correct both eyes for distance and wear readers for near. Second is to correct the dominant eye for distance and the non-dominant for near. Thirdly, the natural crystalline lens can be replaced with a multifocal intraocular lens.
Herpes simplex and herpes zoster are viruses that can affect the eye. Herpes zoster affects the nerve and can affect the inside of the eye as well as surrounding tissues such as the lid. Herpes simplex affects the cornea of the eye. Both of these viruses in the active stage are contraindicated for Excimer laser surgery. If the herpes simplex is inactive, treatment may proceed but anti-viral medications may be necessary as a precaution.
Corneal thickness is measured by pachymetry. If the thickness is less than 450 microns the individual may not be a candidate for Excimer laser. Advanced Surface Ablation is a safer procedure than LASIK because the cornea is thinned less.
Corneal endothelial dystrophy is a disease of the inner layer of the cornea and is a relative contraindication to laser surgery.
Abnormal closure of the eyelids or conditions that allow the lid to turn in or out should be corrected before Excimer laser surgery is considered
One eyed patient should have all the risks carefully explained to them. Although, the results with the Excimer laser are excellent, rare complications may occur. The patient must weigh the risks and benefit before making a decision to have laser surgery.

References

Buratto,L. and Brint, S.: Custom LASIK: Surgical Techniques and Complications. Thorofare, N.J.Slack. 2003 p161-287. [book]

Mrochen M et al.. Increased higher-order optical aberrations after laser refractive surgery: a problem of subclinical decentration. J Cataract Refract Surg 2001 Mar; 27 (3): 362-369. [pubmed]

Schwiegerling J, Snyder RWl Corneal ablation patterns to correct for Spherical aberration in photorefractive keratectomy. J. Cataract Refract Surg 2000 Feb; 26(2): 214-221. [pubmed]

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Chapter 5- Pre-operative Workup Part I

2005-10-04T03:31:00.000-07:00

The pre-operative examination is the same for all refractive surgeries. It should include the following:

General medical history
Ocular history
Examination of the ocular adnexa
Anterior segment slit lamp examination
Quantitative and qualitative evaluations of lacrimal function, especially with a history of dry eye syndrome
Contact lens history
Evaluation of blink reflex
Dilated fundus examination
Intraocular pressure
Computerized corneal topography
Visual acuity
Manifest and cycloplegic refraction
Biometry
Pupil diameter
Pachymetry (measuring the corneal thickness)
Determination of the dominant eye
Wavefront measurements

The following conditions should be evaluated.

Diabetes-well controlled diabetics are better candidates than insulin dependent and poorly controlled diabetes. Diabetes is a relative contraindication.
Pregnancy/ breast feeding- both conditions are a contraindication to laser surgery. The patient should wait at least six weeks following delivery and breast feeding before having laser surgery.
Autoimmune/connective tissue diseases such as rheumatoid arthritis, systemic lupus erythematosis, scleroderma and nodular panarteritis are contraindications to Excimer laser treatment. Wound healing is unpredictable with these disorders.
Immunodepressed patients are at a higher risk for infection and therefore are a relative contraindication for Excimer laser treatment.
Systemic infections such as HIV and tuberculosis are relative contraindications for Excimer laser surgery.
Previous eye surgery such as retinal detachment, vitrectomy, cataract and glaucoma surgery need to be individually assessed as to the appropriate treatment.
Cataract is the clouding of the natural crystalline lens. The removal of the lens and placement of an intraocular lens should be considered instead of refractive surgery for older patients with cataract. The surgeon aims to reduce or alleviate the need for glasses after the cataract surgery.

References

Buratto,L. and Brint, S.: Custom LASIK: Surgical Techniques and Complications. Thorofare, N.J.Slack. 2003 p161-287. [book]

Mrochen M et al.. Increased higher-order optical aberrations after laser refractive surgery: a problem of subclinical decentration. J Cataract Refract Surg 2001 Mar; 27 (3): 362-369. [pubmed]

Schwiegerling J, Snyder RWl Corneal ablation patterns to correct for Spherical aberration in photorefractive keratectomy. J. Cataract Refract Surg 2000 Feb; 26(2): 214-221. [pubmed]

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Chapter 3- What is Advanced Surface Ablation?

2005-10-04T03:09:00.000-07:00

Advanced Surface Ablation is removing the epithelium from the cornea and treating the refractive error on the front surface of the cornea. I use a VISX laser and my comments relate to the VISX laser.

The epithelium can be removed several ways. The oldest method is to scrape the epithelium off with a blade. The disadvantage with this method is that there may be incomplete removal of the epithelium and damage to Bowman’s membrane (the layer just below the epithelium).

A second method is removal of the epithelium with the laser. This treatment parameter only allows the epithelium to be removed to 6 mm and now the new treatment zone extends to 8 mm. Enlargement of the treatment zone reduces the night vision symptoms.

A third method of epithelial removal is Epilasik. With this method a suction device is placed on the eye to hold it, and a blunt blade is used to remove the epithelium in a sheet. The sheet is replaced after the Excimer laser treatment.

A fourth method is the use of alcohol. A dilute solution is used on the eye in a 9 mm holding cup for 30 seconds. Dilate alcohol loosens the epithelium so it can be moved to one side or totally removed, in preparation for the Excimer laser treatment.

With all four of these methods, a contact lens should be worn on the eye after the surgery to allow the epithelium to regenerate. All of these techniques have more pain than LASIK. All of these techniques have a slower return of vision than LASIK.

There are three advantages to these techniques over LASIK. The first is that it is a safer procedure. Cutting a flap weakens the cornea and with treatment, tissue is removed and the cornea is further thinned. Thus, Advanced Surface Ablation is safer than LASIK. The second advantage is that the complication rate is less. LASIK has complications from bad flaps, slipped flaps, diffuse lamellar keratitis and epithelial ingrowth. The third advantage is that when a “finger-print” of the eye (i.e., wavescan) is performed before surgery, the laser can treat all these components. When a LASIK flap is cut, higher order aberrations (horizontal coma) can occur. Since these occur after the wavescan test was performed, these abnormalities are not figured into the treatment plan. Thus, Advanced Surface Ablation is safer and more accurate.

References

Carones F, Vigo L, Carones AV et al. Evaluation of photorefractive keratectomy retreatments after regressed myopic laser in situ keratomileusis. Ophthalmology 2001; 108 (10): 1732-1737. [pubmed]

El-Agha MS, Johnston EW, Bowman RW et al. Excimer laser treatment of spherical hyperopia: PRK or LASIK? Trans Am Ophthalmol Soc 2000; 98: 59-66. [pubmed]

Hersh PS., Brint SF, Maloney RK, et al. Photorefractive keratectomy versus laser in situ keratomileusis for moderate to high myopia. A randomized prospective study. Ophthalmology 1998; 105 (8): 1512-1522. [pubmed]

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Chapter 1 - What is LASIK?

2005-10-04T02:49:00.000-07:00

LASIK is a surgical procedure for refractive errors. It consists of placing a suction device on the eye and using an oscillating blade to cut a circular flap of the cornea. The thickness of this flap depends on the surgeon but can vary from 100 microns to 180 microns (i.e., one to two tenths of a millimeter). The corneal flap is lifted and the Excimer laser is used to treat for the desired refractive error. An alternate procedure is the utilization of a laser to cut the flap (Intralase). To protect the eye from thinning excessively after surgery, the corneal bed needs to have a residual corneal bed of 250 to 300 microns. Measurement of the corneal thickness (a procedure called pachymetry) is very important.

References

Carones F, Vigo L, Carones AV et al. Evaluation of photorefractive keratectomy retreatments after regressed myopic laser in situ keratomileusis. Ophthalmology 2001; 108 (10): 1732-1737. [pubmed]

El-Agha MS, Johnston EW, Bowman RW et al. Excimer laser treatment of spherical hyperopia: PRK or LASIK? Trans Am Ophthalmol Soc 2000; 98: 59-66. [pubmed]

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Foreword

2005-10-03T21:16:00.000-07:00

Dr. Hampton Roy is an accomplished author and ophthalmologist. His career as an author has produced over 30 published books, and Dr. Roy is the Chief Editor of eMedicine.com/ophthalmology. As a physician, he manages his general ophthalmology practice in Little Rock, Arkansas where he is a LASIK refractive surgeon.

This book is a guide for young refractive surgeons, non-ophthalmologists, and patients who would like to understand the fundamentals of refractive surgery. Dr. Roy researched the topics discussed and contributes his own expertise. He explains both the advantages and disadvantages of this increasingly popular surgery and provides the reader basic knowledge to help them understand the risks and benefits of refractive surgery.

Andrew Doan, MD, PhD
Ocular Pathology Fellow
Jules Stein Eye Institute

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LASIK and Advanced Surface Ablation

LASIK and Advanced Surface Ablation by Hampton Roy, M.D.

Chapter 7- Dry Eyes and Refractive Surgery

Chapter 4- Complications of Advanced Surface Ablation

Chapter 2- Complications of LASIK Surgery

Chapter 11- Options for Presbyopia

LASIK and Advanced Surface Ablation

Table of Contents

Chapter 10- Surgical Outcomes

Chapter 9- Wavescan and Excimer Lasers

Chapter 8- LASER TREATMENT AFTER PREVIOUS SURGERY AND SPECIAL CASES

Chapter 6- Post-Operative Pain Management

Chapter 5- Pre-operative Workup Part II

Chapter 5- Pre-operative Workup Part I

Chapter 3- What is Advanced Surface Ablation?

Chapter 1 - What is LASIK?

Foreword