For those who would prefer to correct their eye aberrations without glasses or contact lenses, LASIK is the obvious choice. LASIK, the short for laser in situ keratomileusis, is the most prevalent surgical practice in correcting refractive errors of the eye for those who can afford it.

Though a surgical and reversible procedure, LASIK has gained immense popularity for its encouraging outcome in its aim to provide better vision than glasses and lenses, its adaptability and its constant endeavor to ensure better quality unaided vision. In 1995, it was approved by the Food and Drug Administration in the US.

The eye conditions that lasik corrects

Some of the errors that LASIK can correct are - myopia, hyperopia and astigmatism. The ranges of up to which LASIK works for these errors, however, varies according to clinical analysis of predictability, effectiveness, safety, post-operative stability and condition of eyesight.

LASIK also corrects refractive inaccuracies in the following cases:

• After other refractive practices like PRK, radial keratotomy, intracorneal ring.
• After penetrating keratoplasty, intraocular lens implant after cataract removal.
• With other refractive techniques for very large ametropias (bioptic methods).
• In pediatric cases for certain refractive or strabismus conditions which cannot be effectively corrected with contact lenses and glasses.

LASIK is also being developed further in its ultimate aim to ensure better postoperative vision than that provided by glasses and contact lenses.

A look into the past

The history of LASIK goes back to when Professor Jose Ignacio Barraquer, developed myopic keratomileusis in 1949 in Colombia. This process used a cryolathe for corneal refractive modifications. The term keratomileusis comes from the Greek word keras meaning ‘horn-like’ and referring to the cornea and smileusis meaning carving.

In 1964, Krwawicz developed the technique of raising the corneal cap for removal of the central tissue, which came to be known as keratomileusis in situ. This was further developed by Pureskin in 1967. Later Dr. Luis Antonio Ruiz, pioneered a microkeratome (the apparatus for the procedure) with gears. This made automated lamellar keratoplasty (ALK) possible and hence led to its increased popularity. Another milestone was achieved, when laser technology was introduced as a part of the ALK process.

The LASIK process

The LASIK process involves the lifting of the anterior flap of the cornea with a keratome and the application of an excimer laser to remove, add or modify the stromal surface and hence achieve refractive correction of a wide range of errors.

Preoperative tips

There are a few diagnostic points to remember before the surgery:

• The minimum age for LASIK is normally 18 years, other than specific pediatric cases.
• Cases must be chosen for LASIK on the basis of how successful the results may be vis-a-vis other refractive surgeries like radial keratotomy, PRK, or laser subepithelial keratectomy (LASEK).
• Patient counseling and informed approval is vital.
• A check of the refractive stability of the patient is essential before the operation for ensuring enduring effects.
• Potential cases must be subjected to a comprehensive eye screening (visual acuity, refraction, computerized videokeratography, wave front analysis, slit-lamp examination, retinal evaluation, eye dominance testing and tests for monovision where applicable).
• LASIK is unsuitable for cases with keratoconus or active corneal or ocular ailment and pregnant or lactating women.
• For patients using contact lenses, they should be discontinued for corneal stability.
• All cases should be evaluated for central corneal thickness to determine the safe confines of corneal stromal elimination.

Operative preparation and procedure

• Preparation of the patient in a sterile manner.
• Treatment of the eye with topical anesthetic drops.
• Oral sedation 45 minutes before the surgery. The patient should be just relaxed and not over sedated, since the surgery requires patient involvement to ensure correct fixation.
• Standard surgical skin and eye preparation.
• Correctly preparing the apparatus and the laser suite, as both affect the outcome of the process.
• Keratectomy: A process that readies the patient for the surgery with marking of the corneal epithelium, determination of the thickness of the incision, placing of the LASIK pneumatic suction ring etc.
• Laser ablation is the core of the surgical process.
• Replacing of the corneal flap is the closing step.
• Right after surgery the patient is administered one drop of antibiotic and non-steroidal anti-inflammatory agent.
• An orbit guard is placed, without any pressure patch.

Advantages and disadvantages of lasik

Benefits of LASIK include:

• Potential to correct a wide range of refractive errors effectively.
• Speedy recovery.
• Relatively painless process.
• Comparatively comfortable healing.

Drawbacks of LASIK are:

• Risk of serious side effects.
• Huge costs.
• Risks involved with lack of technical expertise.
• Problems associated with effectiveness, predictability, safety, and stability.
• Microkeratome-related complications, laser-related complications, intraoperative complications, postoperative infection and other and rare complications like dry eye symptoms, forme fruste keratoconus, diffuse lamellar keratitis etc. But none of these pose a threat to eyesight.