LASER EYE SURGERY

What is Laser Eye Surgery?

Laser eye surgery is a procedure using an Excimer laser to change the curvature of the front surface of your eye.

What is an Excimer Laser?

An Excimer laser mixes and charges Argon and Fluoride gases to produce a cold beam of ultraviolet light.  Each pulse from the Excimer laser precisely breaks molecular bonds without heat damage to adjacent cells.

How does the laser affect an eye?

The front surface of an eye is called the cornea.  The cornea is like a watch crystal in that it is transparent and very strong.  The cornea is about ½ mm thick and has five layers.  The corneal curvature is responsible for about 60% of the light bending (refractive) power of an eye.  As the laser precisely vaporizes corneal tissue it creates a small change in corneal curvature which results in a large change in the focusing of light inside the eye. 

What are the benefits?

Most people who have laser surgery are tired of wearing glasses or hate to wear contact lenses.  Others want the freedom to wake up in the morning and see the alarm clock, to see the soap in the shower or play sports free of sight correcting eye wear.

What is a successful outcome?

Laser eye surgery will reduce or possibly eliminate the absolute need for glasses or contact lenses for distance vision.  It is important to have realistic expectations of what the outcome will be in order to avoid disappointment.  Successful patients understand that this type of treatment is elective and intended to enhance quality of life by providing freedom from the absolute dependency on glasses or contact lenses. 

Limited Success

Even successful outcomes may require a minor prescription pair of glasses for driving at night in the rain or going to the movies.  There may be a reduction in contrast sensitivity.  Almost everyone over the age of 40 requires reading glasses with or without laser eye surgery.

Alternatives to Laser Eye Surgery:

• glasses
• contact lenses
• continuous wear or single use contact lenses
• orthokeratology (putting on a contact lens at bed time, taking it off when you wake up and being able to see for the rest of the day.)

Who is a good candidate?

Good candidates for laser eye surgery are healthy people with healthy eyes who have no prior history of significant ocular disease or injury.  Almost anyone with stable vision may be considered.

How predictable is Laser Surgery?

Outcomes are predicted based on an eye’s initial refractive power, the type of procedure chosen, the type of laser used and from analyzing previous patients who have had laser surgery.  Like any surgery, the outcome is largely surgeon dependent.  Each refractive surgeon must independently choose the appropriate sculpting technique and modify the computer algorithms to match the needs of an individual eye.  Great care must be given to align the patient during the time of treatment to ensure that the treatment area (ablation zone) is centered with the patient’s line of sight.  As the clinic sees the outcomes from a variety of laser clinics, our Optometrists will be able to recommend surgeons who have an excellent record of successful outcomes.  We are independent health care providers and our recommendations are made at arms reach with your best interests in mind.  We do not hold any financial interest or affiliation with any laser eye centre. 

Two procedures to choose from: 

1.      Photorefractive Keratectomy - PRK is a surface treatment of the cornea which has been used world wide since 1987.  With PRK, anesthetic drops are applied to the surface of the eye before the surface cells (epithelium) are gently brushed away.  “No Touch” PRK is a trademark referring to trans-epithelial PRK where the laser is used to remove the surface epithelium.  The laser then sculpts the underlying “stromal” layer.  A bandage contact lens is worn for about three days until the surface cells cover a  6mm wound.  Once the lens is removed, patients can expect visual recovery by about one week.  Steroid eye drops are used for at least 3 months to control recovery. 

2.      Laser Assisted Intrastromal Keratoplasty – LASIK is a procedure where a flap 1/3 of the corneal thickness is generated using a micro keratome.  The laser then sculpts the underlying “stromal” layer.  The flap is set back in place to cover the treatment area.  Painless visual recovery is almost immediate and will stabilize in about one month.  Prescription drops are used for up to two weeks.  The human healing response is complete at about three months post-op. 

LASIK vs PRK

Both methods yield excellent results however more than 95% Of all refractive surgeons would prefer to do LASIK rather than PRK.  As least 80% of all refractive surgeries in the world are LASIK. 

Wavefront Technology

Wavefront analysis identifies eyes which have pronounced corneal aberrations.  This advanced treatment is beneficial to about 20% of the population – it is not necessary or beneficial for all patients. 

Our Laser is Better Than Their Laser

Don’t believe everything you read.  We will make strong recommendations based on fact of who you should see for your best outcome. 

What are the Risks?
For PRK & LASIK

1. Dry Eyes – due to the cutting of sensory nerves.
2. Infection – Close monitoring and the use of antibiotics makes infection an extremely rare event.
3. Irregular Astigmatism – more likely with LASIK than PRK.  Minimized by the use of new “wavefront” technology.
4. Overcorrection/Undercorrection/Regression – about 3% of patients require retreatment.
5. Light Sensitivity – more common with PRK especially during the first 3 days post op.
6. Contact Lens Intolerance – more likely with PRK as a bandage lens is seldom used with LASIK.
7. Corneal Haze – a change in corneal transparency exacerbated by an aggressive healing response.  Haze is more likely to be seen with very high correction, is usually temporary and seldom effects vision.  It can be controlled with prescription eye drops and lubricants and is less likely to develop with LASIK.  May be uncontrollable in some cases.
8. Halos/Glare – usually transitory.  More likely to be seen with light coloured eyes and on eyes treated with a laser with a small treatment zone.
9. Reduced Contrast Sensitivity – a reduced ability to discern between “shades of gray”. 

For PRK:
1.      Delayed Healing – about 5% of eyes require extra time with a bandage contact lens.
2.      Elevated IOP – about 5% of eyes require added drops to control a rise in eye pressure          caused by the steroid medications used after surgery. 

For LASIK

1. Corneal Perforation – there is the remote chance that the keratome could cut too deep and perforate the eye causing a corneal cap instead of a corneal flap.
2. Vascular Occlusion – there is a remote chance that blood flow could be cut off to the light sensitive layer in the eye (the retina) causing permanent vision loss.
3. Edema/folds in the flap – a poorly generated flap or complicated procedure could result in a swelling of the flap which may take months to recover.
4. Dislodged Flap – the flap is vulnerable to being dislodged especially during the first two months. 
5. Subconjuncitval Hemorrhage – a minor amount of bleeding seen on the surface of the eye is not uncommon and is self limiting.
6. Epithelial Ingrowth – surface cells may grow under the flap; other debris may be there too.  The flap can be surgically lifted and cleaned if necessary.

What is my first step?

Your first step is to have a comprehensive eye examination.  Following that examination your optometrist would be able to tell you whether or not you would benefit from this procedure and what your probable outcome could be.   

Our clinic has provided pre and post operative services in concert with refractive surgeons since 1994.  Here are some of the laser surgery centres who have referred patients to us for post-op care: 

• Pacific Laser Eye Centre, Vancouver BC
• VisionMed, Vancouver, BC
• Broadway Eye Surgery Centre, Vancouver, BC
• London Place Eye Centre, New Westminster
• Gimbel Eye Centre, Vancouver, BC
• Gimbel Eye Centre, Calgary, Alberta
• Mitchell Eye Centre, Calgary, Alberta
• TLC – The Laser Centre, Toronto, Ontario
• TLC – The Laser Centre, Vancouver, BC
• Bochner Eye Institute, Toronto, Ontario
• Beacon Eye Centre, Toronto, Ontario
• Lasik Vision Canada, Vancouver, B.C.
• Victoria Laser Centre, Victoria, B.C.
• Valley Laser Eye Centre, Abbotsford, B.C.