Updated: 09 Jul 2007

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Introduction

In the past 10 years 70,000 Kiwis have had their eyes lasered in the hope of throwing away their glasses.

Most people are happy with the results, but there are risks involved.

Our report looks at the pros and cons of laser eye surgery, the cost, types of surgery available, and considers alternative options.

Overview

Laser eye surgery can correct common eye disorders such as short-sightedness, long-sightedness (in some people), and astigmatism (depending on the type and the severity). See "An insight into eyesight" below.

The surgery works by re-shaping the cornea - the front surface of the eye. The cornea is flattened for short-sighted people, sculpted to a steeper curve for far-sighted people, and evened out to correct astigmatism. It's all over in a flash - the entire surgery takes less than 15 minutes.

There are seven laser-surgery clinics in New Zealand and all clinics use trained ophthalmologists (eye specialists who go through medical training before specialising). They are qualified to diagnose and treat a wide range of eye diseases and also carry out eye surgery.

All surgeons are Fellows of the Royal Australian and New Zealand College of Ophthalmologists.

An insight into eyesight

The eye works like a camera - its primary function is to focus light.

For the eye to see, light rays must be bent or "refracted" to meet at a single point through the cornea. The cornea at the front of the eye provides most of the focusing power.

In the normal eye, light rays pass through the cornea and the lens behind it focuses them as a sharp image on to the retina at the back.

"6/6" vision is the term for normal vision. The old term for 6/6 "normal" vision was 20/20, referring to feet instead of metres. A person with 6/12 vision can see at six metres what a person with normal vision can see at 12.

Images are blurred or distorted when the cornea or eye is misshapen.

The most common vision distortions are myopia (short-sightedness or blurred distant vision), hyperopia (long-sightedness or blurred close-up vision), and astigmatism. In astigmatism the cornea is uneven, leading to blurred vision at all distances.

Who's suited to laser surgery?

Some people don't suit laser eye surgery. Your eye surgeon should do a detailed medical check. They'll be able to advise your suitability for the treatment.

You may be a good candidate if you:

• are at least 20 years old and have stable eyesight (your prescription should have been stable for at least one year)
  
  
• have eyes free from retinal problems, corneal scars, cataracts, and eye disease
  
  
• have mild to moderate vision problems (within what can be treated).
  
  

You may not be a good candidate if you:

• are pregnant (because the refraction of the eye may change during this time)
  
  
• have an ongoing medical condition such as advanced glaucoma or diabetes
  
  
• are extremely short- or long-sighted
  
  
• have presbyopia (this is an age-related loss of ability to focus on near objects; it often can't be corrected by laser eye surgery).

How it's done

There are two main types of laser eye surgery:

• Surface treatment (also known as PRK, LASEK or EpiLASIK)
  
  
• Treatment performed under the corneal flap (LASIK).

The best type of surgery for you depends on how bad your eyesight is, the thickness of your cornea, and your lifestyle.

Surface treatments

Surface laser or PRK (photorefractive keratectomy) was the first technique available. A portion of the top layer of the cornea is scraped off and the laser reshapes the surface of the cornea.

PRK is a more simple procedure than LASIK (see below). PRK is more suited for correcting lower degrees of short-sightedness and astigmatism, or if you have a thin cornea. It may also be recommended if you play high contact sports, such as rugby league, because there's no corneal flap to heal.

LASEK (laser assisted subepithelial keratomileusis) and EpiLASIK (using a finer tool) are based on PRK. The top layer of the cornea is pushed aside during surgery and replaced afterwards to preserve more corneal tissue.

In LASEK the outer layer of the cornea is loosened with a weak alcohol solution, while in EpiLASIK the skin is removed with an electromechanical device. Both procedures still involve laser surgery on the surface of the cornea.

Recovery from PRK, LASEK and EpiLASIK can be uncomfortable and will take about a week. There's a higher risk of visual problems, such as corneal haze or blurry vision.

Inside-the-cornea techniques

The most commonly performed surgery is LASIK (laser in-situ keratomileusis). A tiny flap is created in the outer layer of the cornea, so that a laser can reshape the tissue underneath. The flap is placed back over the treated cornea and it sticks naturally.

The original LASIK procedure used a miniature scalpel (called a microkeratome) to cut the flap. The flap was left attached to the cornea by a "hinge". The bed beneath the flap was reshaped using the laser and the flap replaced.

LASIK is less painful and has a lower incidence of post-operative haze and regression than surface treatments. Recovery is rapid (around 12 hours). LASIK is more suited to severely short- or long-sighted people. But there's a small risk of surgical complications from the surgical blade.

In newer procedures a thinner flap is created with a computer-guided laser, often called by its brand name IntraLase. With "blade-free" IntraLase LASIK there's a lower risk of infection and a lower risk of cutting a poor-quality irregular flap.

What's the best method?

Unfortunately experts disagree over whether LASIK or surface techniques are best.

Dr David Prendergast, from Auckland Eye, Dr Tony Morris, from the Eye Institute, and Dr David Kent, from the Fendalton Eye Clinic, perform IntraLase LASIK. Dr Prendergast and Dr Morris believe there's no question IntraLase LASIK is the safest method.

Dr Kent said: "IntraLase is a significant safety advance because the worst risk with LASIK was the problems with the microkeratome blade. This risk is removed with IntraLase."

Although Dr Andrew Logan from the Wellington Eye Centre has had LASIK surgery, his centre has stopped doing the procedure because of the risk of complications from cutting the corneal flap. He believes EpiLASIK has excellent safety results and these are as good as, or better, than PRK and LASIK.

Some optometrists share Dr Logan's concern. A Wellington optometrist told us he was concerned about any procedure that cuts the corneal flap.

People who have had laser eye surgery may have restricted their options for detecting and treating glaucoma.

People need to be aware that as they get older their vision may naturally deteriorate and it's likely they will need reading glasses.

The Royal Australian and New Zealand College of Ophthalmologists considers that PRK, LASEK, EpiLASIK and LASIK are acceptable surgical procedures for the correction of refractive errors such as short-sightedness, long-sightedness, and astigmatism.

What does it cost?

Clinics we consulted charged between $2100 and $2900 per eye, which usually includes a free consultation.

The costs vary depending on the type of procedure and the technology used. IntraLase LASIK (see How it's done) tends to be more expensive because of the equipment used.

You probably won't be able to cover the costs of the surgery through your medical insurance because glasses or contact lenses can correct your vision problems.

About 3 to 5 percent of operations require an enhancement procedure to fix an under- or over-correction. Make sure this is included in the cost.

Some of our members told us they were considering having the surgery done in Asia, where it was cheaper. However, specialists here warn against this. The machinery may be second-hand, you may need an enhancement procedure at a later date, and you don't know how experienced the surgeon is. After all, you only have one pair of eyes.

Across the Tasman the cost is comparable to here. A report by the Australian consumer organisation Choice found that on average clinics were charging A$2500 per eye.

Many members told us the cost of surgery paid for itself within a few years - you no longer had the continuing costs of contact lenses, solutions, optometrist appointments, and glasses.

What can go wrong?

Laser eye surgery is an invasive surgery, so there is some risk. The most common problems include:

• Over- or under-correction - this often corrects itself but you may need to wear glasses or contact lenses part- or full-time. A "fine-tuning" enhancement can be done after three months.
  
  
• Visual problems - these include corneal haze, glare, starbursts around lights, blurry double vision, light sensitivity, and shadow images. These symptoms are more common after PRK (see How it's done). They usually fade but can seriously affect night vision. For some patients these aren't minor problems. You may have to stop driving at night, and you may find doing things in dim light impossible.
  
  
• Dry eyes - the inability to produce enough tears can be uncomfortable. After menopause, women are more susceptible to dry eye, especially if they are on hormone replacement therapy.
  
  
• Eyesight regression - eyesight returns to how it was before the surgery. In some cases vision can be worse.
  
  
• Infection and inflammation - this delays healing and can lead to corneal scarring.
  
  
• Flap damage (LASIK only) - instead of creating a hinged flap of tissue, the entire flap may come off. There's a risk of damage, and the flap may be lost.
  
  
• Distorted flap(LASIK only) - irregular healing of the corneal flap could create a distorted corneal shape. This affects corrected vision.
  
  
• Eye sensitivity - especially after PRK or other surface treatments.
  
  

Realistic expectations

If your vision problems are mild to moderate, there's a good chance you can throw away your specs or contacts. But if you're very short-sighted, you may still need them for driving or watching movies.

Success depends on your expectations. Researchers found that 95 to 97 percent of patients were happy with the outcome, even though up to 20 percent of them had what others might consider unacceptable side effects.

Some people are prepared to make trade-offs: the positive aspects from improved vision in other parts of their life may make up for the inconvenience of not driving at night.

Your experiences

We asked our members to tell us about their experiences with laser eye surgery. We were overwhelmed with the response.

More than 160 members responded and the majority were very happy with their surgery results. Our thanks to everyone who contacted us.

For Consumer member June Stanbury, laser eye surgery is the best money she's ever spent. "I've suffered from short-sightedness since my teens and have worn contact lenses for 38 years. The freedom is worth the cost.

"The procedure was painless, my distance vision has been restored to normal, and I've had no problems since the operation."

Erin Billing agrees. "It was over so quickly and the freedom I've gained is amazing. I went white-water rafting and had to smile when I realised I couldn't lose my glasses or contacts."

But other members aren't so satisfied. The surgery left Dorothy Simpson with severely dry eyes. "I've spent a lot of money on eye drops and special glasses, as well as visiting other specialists."

Other members have also experienced dry eyes and vision problems.

More members' comments

Kira Bacal

"I love it. I'd recommend it to others - but make sure you do your homework and go to the best surgeon you can find. Most people lose some vision with age so it's important to know the surgery isn't a cure-all. After nearly 10 years my vision is slowly starting to erode."

Sue

"It's great not to wear glasses or contacts, but so far I'm not happy with my vision. It's taking a long time to improve and may need an enhancement. The surgery was painful but I think I underestimated the procedure."

Cheryl Redit

"No fumbling for glasses at night, no more streaming eyes from dirty contacts on a windy day, no more mucking around cleaning contacts every day. I would recommend it for convenience."

Ron Keen
(pictured below) "It's wonderful to go tramping and cycling in the rain without having to wipe my glasses."

Alternatives to laser surgery

Glasses

Glasses are safe, easy to maintain and relatively low cost (costs vary depending on frames, lenses, and special coatings). But they may interfere with sporting or work-related activities.

There are a number of special lenses available:

• Bifocals devote a portion of their lower half to reading.
  
  
• Trifocals add an intermediate zone for mid-range viewing.
  
  
• Progressive lenses change power progressively as eyes move from top (distance) to centre (intermediate) to bottom (near). Peripheral vision is diminished, which can make objects at the sides seem to "swim" - most wearers adjust to this over time.
  
  
• Aspheric lenses are flatter than the usual convex lenses, which can make eyes look more natural.
  
  
• Photochromic lenses darken quickly in the sunshine but take longer to lighten indoors, which can be dangerous.
  
  

Contact lenses

Contact lenses give you more freedom, can increase peripheral vision, and improve cosmetic appearance.

• Continuous-wear 30-day contacts are the least hassle. You don't have to put them in every morning and take them out and clean them every night. There are concerns about these lenses because they have been linked to infections. Modern silicone hydrogel contact lenses have reduced this risk. A six-month supply will cost about $360.
  
  
• With daily disposables there's no cleaning hassles but they are an expensive option. A six-month supply is around $500.
  
  
• Daily wear two-weekly or monthly disposables must be taken out and cleaned daily. They're not as convenient as continuous-wear or daily disposables but are cheaper. You'll pay about $230 for a six-month supply and an extra $40 for solution.
  
  
• Conventional soft lenses are worn daily for a year or more. You take them out at night and clean them. Prices vary depending on your prescription but they can cause an infection if they're not cleaned properly.
  
  
• Rigid gas-permeable lenses present fewer infection risks. They're custom-made and cost around $400 a pair. They usually last between one and two years.
  
  

It's essential you care for your contact lenses properly to avoid contamination.

Buying a three-month supply of contact lenses online may save you more than $100. Before you order, make sure your prescription is current: the New Zealand Optometrists Association recommends an annual eye check.

Surgical options

Implantable contact lenses are an option if you have extreme vision problems and are unsuitable for laser eye surgery. Unlike regular contacts, they're placed permanently inside the eye behind the iris. Only one eye is operated on at a time and prices vary depending on your prescription.

The US Food and Drug Administration consider implantable contact lenses to be safe and effective. Researchers are tracking the long-term results.

Our advice

• When considering laser eye surgery, get all the facts about risks and complications so you can make an informed decision. No corrective eye surgery is 100 percent safe or successful.
  
  
• Be realistic. If you're expecting perfect vision you might be disappointed.
  
  
• Your GP, optometrist, or ophthalmologist may be able to recommend a laser eye surgeon. However, ask them if they get a "referral fee" from the laser eye clinic. We've heard of cases where this happens.
  
  
• Ask what the surgeon's experience is with correcting the type and degree of your vision problem. Ask for data on their surgery outcomes. Choose a surgeon who is a Fellow of the Royal Australian and New Zealand College of Ophthalmologists (look for the letters FRANZCO or FRACO after their name).
  
  
• Don't go by cost alone. Does the price include check-ups and enhancement procedures? These may be necessary if the first operation leaves the eye under- or over-corrected.

More information

• Eye Surgery Education Council: www.lasikinstitute.org
• Royal Australian and New Zealand College of Ophthalmologists: www.ranzco.edu
• US Food and Drug Administration: www.fda.gov/cdrh/lasik

More from consumer.org.nz

• Glasses
• Contact lenses

Report by Belinda Allan