Clear- sighted solutions to those morning fumbles
WAKING up in a blurry room and fumbling for our glasses on the bedside table is the way many of us start our day. According to Optometrists Association Australia statistics, over 480,000 Australians are visually impaired in both eyes.
While some embrace their glasses as a fashion accessory, a growing number are turning to laser technology in the hope of ditching the specs for good.
It’s a tempting option, considering that over half of these visual impairments are easily correctable.
A majority are due to refractive error, which relate to the focusing of light.
LASIK, today’s most popular form of laser eye surgery, has become an increasingly reliable, predictable and safe method of correcting refractive error over the past 15 years.
Along with other technological advancements, LASIK’s rise in popularity has been aided by the willingness of high profile figures, such as Tiger Woods and Jessica Simpson, to put themselves before the beam.
Royal Australian and New Zealand College of Ophthalmologists ( RANZCO) president, Dr Iain Dunlop, says technological advancements have opened up the procedure to a broader range of people.
He says: Laser is much more sophisticated now. It has moved from experimental to mainstream.’’
When it was first developed, LASIK was only able to treat myopia or short- sightedness.
It remains most successful for simple low severity short- sightedness, but is now a reasonably successful treatment for middle severity long sightedness ( hyperopia) and astigmatism.
For patients who fall into the former category, there is a 90 per cent chance of achieving at least 6/ 12 vision, which is the legal requirement for driving in most Australian states.
This means that at six metres, a patient will see the same as what a person with normal vision sees at 12 metres ( the metric equivalent to 20/ 20 vision).
To be eligible for the surgery, patients must also be be over 18, and their eye prescription should have been stable for two years. Otherwise, if their eyes are still changing, they may be overcorrected and require further surgery.
One of the factors contributing to the broader application of LASIK surgery is the development of a laser used to cut through the outer layer of the cornea, the eye’s window’’.
To begin the procedure, the surgeon cuts a tiny flap in the cornea to allow a laser to reshape the tissue underneath. The flap is then placed back over the treated area.
Initially, a high- speed blade was used to create this flap, but now a fast, computer- guided laser, known as a femtosecond laser or, by brand name, as IntraLase, is available. Dr Dunlop estimates that over one quarter of clinics now use the latter technology, and expects the roll- out to continue.
The femtosecond has the ability to make different shapes and different types of flaps,’’ he says. It’s safer and more adaptable.
Nowadays you can treat long- sightedness and astigmatism and abnormal shapes more successfully.’’
While LASIK has gained popularity over the last decade, prior to that, a procedure called PRK ( photorefractive keractectomy) was the most common.
In this technique, the surgeon scrapes off a thin layer of the cornea, rather than cutting a flap. A laser is then used to reshape the surface of the cornea. The surface cells do grow back and usually heal within three to five days, but significant discomfort can result in the meantime.
With LASIK, on the other hand, the eyes usually feel quite comfortable the day after surgery, and patients can resume most normal activities.
There is, however, a small additional risk of surgical complications with LASIK which are not associated with PRK.
Phototherapeutic Keractectomy ( PTK) uses a similar procedure to PRK, but is used for the removal of surface irregularities on the cornea.
The main risks of refractive laser surgery are infection and scarring, but, according to Dr Dunlop, the risk of those occurring is now less than one in 5000: ‘‘ It has a very broad acceptance,’’ he says. ‘‘ It’s very safe in medical terms, but it is still discretionary, and with discretionary surgery, even small risks are considered significant.’’
In terms of side- effects, the most common are blurring, glare, halos, light sensitivity and uncomfortably dry eyes.
Most of these complications can be fixed with extra treatment or extra time,’’ Dr Dunlop says.
For short- sighted people, undergoing laser eye surgery increases the probability of them needing reading glasses in later life.
As Shirley Loh, professional services manager for the Optometrists Association Australia explains: Your eyes are being changed to become closer to normal sight, and like every other person with normal vision, there’s a chance you will need reading glasses when you get older.’’
But, if you have the surgery at 25, this still means 15 to 20 years of clear vision. One option is to get one eye made for distance and one eye for short sight, but not many people can adapt to this,’’ Ms Loh says.
There’s no perfect solution out there, everything has its advantages and disadvantages.’’
Aside from the treatment of refractive errors, lasers can also be used to treat a number of eye diseases and conditions. One of these is wet macular degeneration. The condition involves blood vessels growing into the macular ( a small, central area of the eye’s retina) and leaking blood and fluid.
These fluids build up under the retina and, eventually, scar tissue forms which severely deteriorates vision.
Unlike refractive procedures which reshape the cornea, treatment for this condition involves a laser which goes through the cornea to burn the abnormal blood vessels in the macular.
With conditions such as glaucoma, the laser is used to make additional holes to enable drainage and ease pressure in the eye.
In both cases, the surgery will not restore vision already lost, but will help preserve the eye from any further degeneration.
Unfortunately for the many people whose vision starts to go downhill as they move towards their senior years, laser technology is yet to deliver a widely successful remedy for presbyopia.
This condition relates to the ageing eye’s loss of the flexibility needed to switch focal points between close and distant objects.
Dr Dunlop describes the search for a treatment for this condition as a holy grail’’ quest.
There’s a lot of work being done trying to replace that function of that muscle or to do what it does in other ways,’’ he says. It has been a pursuit over at least the last 20 years.’’
He says that implant lens technology, combined with laser, is one of the most promising methods. While this is presently available, a number of side- effects make the method undesirable to all but a small percentage of sufferers ( about one per cent).
There are many compromises that people have to accept,’’ Dr Dunlop says. They lose their contrast and have a vague sense of double image wherever they look.
Until these compromises can be reduced or better managed, it won’t become widespread. At the moment, multi- focal glasses or reading glasses are still the best correction for that.’’