By Dr Michael Lawless

In 2012, 80% to 90% of corneal laser surgery is done using a LASIK technique.  Most surgeons use a femtosecond laser designed specifically to cut a flap of cornea and then using a different (excimer) laser to sculpt or change the shape of the underlying cornea, replacing the flap and improving the patient’s vision. 

 The good thing about LASIK is the accuracy, safety and speed of recovery.  Most patients work and drive the day after surgery. Some people however are not suitable for LASIK.  You need to have the right corneal thickness and the right corneal shape (anatomy).  10% to 20% of people do not meet the safety criteria and for these people the majority require surface laser (ASLA or PRK, LASEK etc…it goes under different names).  Surface laser for most ranges is just as accurate as LASIK, but it causes discomfort in the first few days and has a longer recovery time.  The discomfort can be controlled in most people, but occasionally people do get a lot more pain in the first seventy two hours than would be predicted.  Even more important is the speed of recovery.  The vision is fairly variable in the first week or two and can be quite disruptive in terms of returning to driving and work.

 Currently we use a type of bandage contact lens for 4 days and topical medication.  A lot of work is being done on two aspects to improve this.  One is impregnating a contact lens so that it can give a slow release of medication to make the procedure more comfortable. 

 More importantly, from my point of view, is an attempt by Nexis Vision.  (I’m on their Medical Advisory Board) to design a special type of contact lens which will allow good vision in the recovery period.  The contact lens would remain on for approximately one week and would only be removed once the epithelium was smooth and the vision had gone through its healing phase.  It has been tried in a small number of cases in the United States and needs much more work before it would be clinically useful, but if it can manage to speed the recovery of vision to mimic what is achievable with LASIK, it would make ASLA/PRK a much more patient friendly procedure.

 It sounds a simple idea, but is actually quite complex to design a style and type of contact lens which speeds visual recovery without causing harm, and which still allows the penetration of antibiotics and anti-inflammatory drops that are required in the recovery period.  Some bright minds are working on it and it will be very interesting to see how this progresses in the next one to two years, which is about the time line of it being available if the initial pilot studies are any indication.

 It was a pleasure to be asked to be part of the Medical Advisory Board and I am on it with many old friends and collaborators from the United States.

 In fact, the excimer laser wasn’t employed for laser eye surgery until New York ophthalmologist Steven Trokel first used it in 1983. The technology was first used in Australia in 1991.

 Actually a form of ultraviolet laser, the excimer produces energy that can form temporarily-bound molecules (dimers). Called an ‘excited compound’, it gives up its excess energy by undergoing stimulated emission.

 In layman’s terms, the excimer laser is well absorbed, so, rather than burning or cutting, it simply disrupts the molecular bonds of tissue. This means that it can remove exceptionally fine layers of surface tissue.

 And so, while a femtosecond laser is responsible for creating the flap that allows a surgeon access to the surface of the cornea, the excimer laser then reshapes the surface with micron precision.

 And so, next time you hear someone say how excited they are to have been able to thrown away their glasses, remember that an ‘excited dimer’ was partially responsible for it.

 Putting that to one side, here’s the state of our nation in relation to eye health (source NHS surgery 2004-05).

 The numbers affected by eye problems

Over 10 million Australian’s report a long term vision problem – about 50% of the population. In fact, eye issues are the most common health problem experienced by Australians.

• Long-sightedness – 5.3 million claim they are long-sighted
• Short-sightedness – 4.3 million report short-sightedness
• Astigmatism (like being near or far-sighted) – about 850,000 people
• Prebyopia – around 850,000
• Cataract – 350,000
• Glaucoma – 200,000 Macular Degeneration – 100,000
• People who wear glasses or contact lenses – 9.4 million 

Disability

• An approximate estimate is that 50,000 ?50,000 or 500,000? Australians are blind
• A further 430,000 are estimated to have low vision, which can affect how they live e.g. inability to drive
• Most common cause of blindness is age related macular degeneration
• Around 40% of people over 90 years of age have low-vision?

Risk factors

• Age. Visual impairment is far more prevalent later in life, especially from age-related macular degeneration and senile cataract.
• Diet. A high intake of protein, vitamin A and B1 and riboflavin all help to resist cataractdevelopment. High dietary fat is a contributor to macular degeneration, which high fish and leafy green consumption can helpto combat.
• Smoking, alcohol and sunshine. All are known risks to eye health.
• Diabetes. Diabetic retinopathy was present in one third of all diabetic sufferers, as well as causing a higher risk of cataract and glaucoma.
• Family genes. For example, you are three times more likely to suffer from glaucoma if a close family member suffers from it.

Hospitalisations

• Eye issues account for 1 in 30 hospitalisations in Australia
• Cataract procedures are the most common surgery in the country – over 160,000 per year
• $500 million – the approximate cost of treating eye problems in Australia

Primary Care

• Around 190,000 people visited an optometrist or optician within 2 weeks prior to the survey
• 75% of primary eye care is performed by optometrists

Labour Force

• Just over 3,000 people reported their occupation as optometrists and 627 reported ophthalmologist as their occupation
• Just over  50% of eye-related professionals are female, but only one fifth of ophthalmologists are women

 Conclusions

 While these figures aren’t quite current, (rather than saying the figures are not quite current, why not cite the reference and the year so people get the message that way) they are indicative of the proportion of the population who are affected by eye health problems.

 Many of these issues can be treated, or prevented, so it’s very important for everyone to be aware of their eye health.

 If you have any concern about your vision, ensure you see an eye health professional as soon as possible.

 Very simply, corneal transplant surgery wouldn’t be possible unless thousands of generous donors around the world donated their eye tissue, just so others may have the chance to see again.

 Most countries now have eye banks which medically evaluate and distribute eyes that caring people have donated. Eye banks are usually non-profit organisations, which ensure that donations are fully consistent with the benefits and attitudes of major religions.

 Did you know?

 Almost anyone can become a donor. Your blood type doesn’t have to match, your eye color is of no importance, your eyesight doesn’t have to be good and your age doesn’t matter – most donors are 70 or over. In fact, aside from a few specific diseases such as HIV and hepatitis, most causes of death are not significant.

 This is all to the good, because there’s a constant demand for corneal tissue and there will never be too many donors – perhaps you might be kind enough to consider becoming one yourself?

Become a donor

 Firstly, tell your next of kin, so it’s known that you are happy to become a donor at the time of your death.

 Also, you can now register your wishes with the Australian Organ Donor Registry.

For more information just visit their website on www.medicareaustralia.gov.au/public/services/aodr/index.jsp

Early experiments in Japan

The story of refractive surgery is long and not well documented. However, it is known that some early experiments were performed by Tsutomu Sato, a Japanese ophthalmologist, in the 1930s. He made the first attempts at making radial cuts in the cornea to improve vision for military pilots. Unfortunately, there was a high rate of corneal degeneration, so this could not be called a success.

An accident in Russia leads to a breakthrough

In the 1970’s, Dr Fyodorov in Russia was treating a boy who had accidentally broken his glasses, causing corneal lacerations.

To his surprise, as the boy recovered, he realized that the boy’s vision was significantly improved compared to his myopic condition before the accident.

This led Fyodorov to further research refractive surgery, producing a formula that allowed more accurate results than had been previously been attained.

From here, a technique known as radial keratotomy was born, and helped create a renewed interest in the field of refractive surgery. Radial keratotomy was taken up all across the globe, with over 2 million patients being operated on in the USA alone.

Next Stop – USA

Meanwhile during this time, experiments with laser for industrial purposes resulted in the invention of the Excimer laser, which was used to make microscopic circuits in microchips.

In fact, a team of IBM scientists (Rangaswamy Srinivasin, James Wynne and Samuel Blum) were the first to understand and demonstrate the potential of laser to cut organic tissue without causing significant heat damage. This discovery led to Dr Stephen Trokel patenting the use of the Excimer laser for vision correction in 1982.

The New York ophthalmologist went on to perform the very first laser surgery on a patient in 1987 and, from then on, the techniques using Excimer laser were refined and improved extensively.

The LASIK revolution

While the early laser technique, known as photorefractive keratectomy (or PRK) proved to be very successful, it was the appearance of LASIK, first trialed in 1991, that really moved the game on.

LASIK (laser assisted in-situ keratomileusis) proved to be less invasive, leaving the surface of the cornea largely intact, so allowing patients a more comfortable and faster recovery.

 Enter Wavefront-guided LASIK

Waverfront-guided LASIK is a more developed procedure, which applies a spatially varying correction, guiding the computer-controlled Excimer laser with measurements from a wavefront sensor.

It’s essentially a refinement of LASIK and has proved highly successful, achieving a 95.4% patient satisfaction rate amongst patients over a 10 year period. Further support for Wavefront-guided LASIK has come from the US Air Force, who have given the procedure their approval for the vision correction of pilots, finding that Wavefront-guided LASIK produced ‘superior vision results’.

The future?

While laser eye correction has successfully improved the vision and lives of literally millions of people the world over, we can rest assured that development continues and even more successful technologies will no doubt appear in the future.

Although situated in Chatswood, ophthalmologists from each Vision Eye Institute NSW clinic bring patients to the clinic in order to utilise the femtosecond laser. They do this because it’s in their patients best interests.

Dr Michael Lawless, who performed the first laser cataract procedure in the Southern Hemisphere, says that this is a significant milestone in the history of Vision Eye Institute. “Our cataract surgeons in Sydney now use this technology almost exclusively for the procedure. Here in Sydney, we’re part of a select group of ophthalmologists who are helping to make cataract and lens surgery safer .” says Dr Lawless. “We’re very proud to be leading the way.”

The surgeons at Vision Eye Institute who perform laser cataract surgery are once again pioneers in their field, having previously led the way with a number of highly significant advances in Australia for over 20 years.

It’s highly unlikely that you will ever experience this. But, have you ever wondered what really happens?

While pepper spray can cause many adverse symptoms to the body, the eyes will immediately be affected and can cause uncontrollable tearing, involuntary closing of the eyelids, redness, swelling, stinging and temporary blindness. The epithelial layer of the cornea is disrupted, so anyone with impaired corneal integrity ( diabetes, dry eye or recurrent corneal erosion) are particularly susceptible to severe effects than those with good eye health.

Anyone wearing contact lenses will need to remove them as soon as possible – using clean fingers, not skin that’s been in contact with pepper spray. The contact lenses should be thrown away, because they can’t be repaired.

Rubbing affected eyes will only increase the intensity of pain and should be avoided. You can try flushing eyes with a saline solution. Blinking vigorously to encourage tears will also help flush the irritant from the eyes.

Overall, there is no conclusive evidence to suggest that pepper spray will cause permanent damage to the eye, however repeated exposure could certainly cause permanent damage to the cornea.

LASIK has already gained worldwide acceptance as a preferred vision correction procedure, but the National Aeronautics and Space Agency (NASA) wanted to be certain that it was also suitable for their astronauts.

As you might imagine, the need to operate effectively in zero gravity conditions was always going to be difficult if you need to wear glasses or clean your contact lenses. In fact, it wasn’t so long ago that nearsighted individuals couldn’t be considered as potential astronauts as all.

 So, NASA undertook an extensive review of military clinical data, to determine whether LASIK would meet their criteria. What they concluded was that the combination of femtosecond LASIK flag creation and wavefront-guided excimer laser for corneal sculpting provided superior safety and vision. It was then that LASIK won their seal of approval.

 The investigation team, led by Dr Steven Schallhorn (a former Naval captain), concluded that the findings should be influential beyond those wanting to explore outer space – “NASA independently examined advanced LASIK and determined that it was good enough for the astronaut. That should give comfort to patients contemplating have the procedure.” Said Dr Schallhorn.