Vision of the Future

 
 

With laser eye surgery’s reputation for being somewhat unreliable, Alison Lee informs our readers of a potentially more trustworthy alternativeA huge proportion of people worldwide are afflicted with “refractive corrections” of the eye: conditions where the sufferer is unable to focus an image properly onto the retina, resulting in blurred vision. These include myopia (short-sightedness), hyperopia (far sightedness), astigmatism and presbyopia (reading problems associated with age). Such refractive corrections arise when a “mismatch” occurs between the length of the eye and its optical power. This normally happens during childhood growth and although not yet fully understood, is believed to be influenced strongly by genetics.

In developed countries such as Ireland, routine eye tests easily pick up on these defects and prescription glasses can be worn to correct the problem. However many readers will have experienced the inconvenience of breaking, losing or forgetting their glasses, not to mention felt the cost of purchasing regular replacements. These issues, as well as cosmetic considerations, lead more and more people to invest in contact lenses- it is estimate that 28 million people in the USA alone use contacts. These offer a number of advantages- they don’t steam up in humid conditions, they allow for a wider field of vision and they can be worn during sporting activities. But they also have the potential to create a myriad of problems for the wearer. Studies have shown that long term use can thin the cornea (the clear “skin” of the eye) and increase its roughness and curvature. In addition, reusable contacts require regular cleaning with special disinfection agents.

The time and money involved in caring for and replacing glasses and contacts have led many to seek out a more permanent solution to their vision problems. Most people turn to laser eye surgery. However a new corrective therapy for refractive corrections is growing in popularity; “intraocular lenses” (“IOLs”). These are synthetic lenses made of plastic or silicone that are implanted into the eye. Although the principle was originally used to treat cataracts, since 1999 it has been applied to treat correct common refractive corrections like short- or far-sightedness. Intraocular lenses for this purpose are termed “phakic intraocular lenses” and unlike cataract treatments, the eye’s own lens is not removed when the IOL is inserted.

Many people have a phobia about eye surgery, and the idea of having a synthetic lens inserted into your eye may indeed send a shiver down your spine, but in reality the procedure is fairly quick and easy. Although there are many different types and makes of IOLs on the market, a relatively similar surgery is performed for each; a tiny incision is made in the edge of the cornea and the lens is inserted just in front of or just behind the iris. The eye’s own natural lens continues to focus as before, adjusting your vision for distant or close-up sight, but the lens corrects the eye’s natural defect just as spectacles or contacts would, except it sits comfortably and conveniently inside the eye. The procedure takes only about half an hour and most people are back to work the next day.

The rising popularity of PIOLs is understandable considering the risks associate with the biggest “rival” treatment, laser surgery. Startlingly, according to an article published in the journal Review of Optometry, as many as one in six people experience post-laser complications that negatively affect their eyesight. These include permanent dry eye syndrome, deterioration in vision quality and even serious problems such as irregular astigmatism, which can’t be corrected by glasses.

But it must be remembered that IOL implantation is also a surgical procedure, and there are obviously inherent risks involved. Taken together, these hazards form quite a long list, and some are just as serious as those involved with laser eye surgery. They include retinal detachment, cataracts, and corneal clouding due to loss of essential cells that pump fluid from the cornea, keeping it clear and transparent. Also, anyone contemplating this treatment must remember that it may not result in complete correction of their sight problems, and they still may need to use glasses or contacts for certain activities. Another important factor is price: The cost of such a specialised novel treatment is considerable, with one Irish eye surgery clinic quoting prices starting at 1915 euros per eye (the same clinic charges 955 euro for its most expensive type of laser surgery).

However IOLs are the only option for some people whose visual defects render laser surgery impossible – these include people with thin corneas or myopia of between -3.00 and -20.00 diopters. In addition, many of the clinical trials to date have achieved positive results; a British study published in 2010 found that people who underwent IOL implantation surgery instead of laser surgery generally had clearer vision and better contrast sensitivity. That said, IOL implantation surgery is, in medical terms, an extremely new procedure and as of yet, no large-scale studies on long-term outcomes have been carried out.

As with any medical procedure, IOL surgery possesses advantages and disadvantages – it’s up to optometrists and ophthalmologists to advise each individual client or patient in what is the safest option for them. Importantly, it’s also up to individuals to do their homework and achieve a clear understanding of each procedure before surgery. Clients must have the farsightedness to remember that it is their health and safety that is paramount in this decision-making, not convenience and cosmetics.

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