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Correcting my Vision

What are my options?

13800144_xxlRefractive surgery is any form of surgery used to correct vision due to the eye’s focusing problems (or refractive errors). The most popular and well-known being LASIK, for which around 30 million procedures have been performed worldwide. However, is LASIK the right surgery for you? Or are there other forms of refractive surgery that might suit you better? What are the things you should consider when choosing the options?

Refractive Errors

Different forms of refractive surgery can be used to correct different types of refractive errors. Knowing the type of refractive error that your eye has allows you to understand your options better.

Myopia

Myopia or short-sightedness is the most common form of refractive error, where the eye ball is too long or the focusing power of the eye’s lens and cornea is strong. Thus, images from the outside world come to a focus before they reach the retina (the sensory film of the eye). People with myopia can see near objects well, but need corrective lenses to see clearly in the distance.

Hyperopia

Hyperopia or long-sightedness is the opposite of myopia where the focusing power of the eye is too low or the eyeball is too long. Here, the person can see in the distance with some effort, but their near vision is blurry. However, if hyperopia is severe, even distance vision can be impaired.

Astigmatism

Astigmatism is caused by the imperfect curvature of the focusing system of the eye. For example, the cornea of the eye is shaped more like a rugby ball instead of a soccer ball, which is evenly curved. People with astigmatism have blurry vision for both near and distance and may be more bothered by it at night when the pupil is larger.

Presbyopia

Presbyopia is the difficulty reading with age. It is different from long-sightedness in that the cause is due to the ageing of the eye’s lens or age-related changes to the tiny muscles that change the power of the lens, thus losing the ‘auto-focus’ capability that the younger eye enjoys.

Available Options for Refractive Surgery

LASIK

LASIK (or Laser In-situ Keratomileusis) has sometimes been termed a ‘flap and zap’ procedure. Essentially, a partial thickness flap is created on the cornea using a laser or less commonly, a special automated blade. After this, the flap is opened and another laser is used to sculpt the exposed central layer of the cornea, called the stroma, to correct the focus power of the cornea for myopia, hyperopia, or astigmatism. The flap is then replaced and closed without the need for stitches. The whole procedure is done under local anaesthesia using eye drops, with the patient awake. It is a day-surgery and no hospitalisation is required. LASIK can be used to correct myopia, hyperopia, and astigmatism.

If you are like most people who want short downtime and relative comfort after surgery, then LASIK is probably for you. Additionally, if you are known to respond to steroid eye drops with an increase in eye pressure, or have a history of cold sores, then you would benefit from a quick recovery. In such cases, LASIK is the technique of choice.

Advanced Surface Ablation

Advanced Surface Ablation (or ASA) uses the same kind of laser in LASIK to change the power of the cornea. The difference is that, the laser is applied to the surface of the cornea after removal of the superficial layer called the epithelium. This means that there is no LASIK flap to cover the wound, and the epithelium over the surgery site is required to heal over approximately three days. The eye is kept comfortable with a special bandage contact lens that covers the wound. ASA is best for treating myopia below -6D (600 degrees), astigmatism, and low degrees (around 100 degrees) long-sightedness.

If you have a job, lifestyle, or sport which puts you at higher risk of an eye injury, then you may wish to choose ASA as this would reduce the chances of a LASIK flap dislocation as part of an eye injury. If you have a problem with recurrent corneal erosions or if your cornea is too thin for LASIK, then ASA is the recommended choice as it is a good treatment for the former and consumes less tissue for those with the latter.

Implantable Collamer or Contact Lens

The Implantable Collamer or Contact Lens (ICL) is a form of surgery where a lens is inserted behind the iris of the eye to correct refractive error. No laser is used, and unlike LASIK and ASA, this procedure is potentially reversible.

If your eyes are very dry or do not have sufficient thickness for laser refractive surgery, then the ICL may be the better option for you. All you need is to have adequate space in your eye to fit a lens in. A minority of people would not have enough space in the eye for an ICL. Another advantage of the ICL is that it can be used to treat high levels of myopia and astigmatism, e.g. myopia greater than 1000 degrees and has been found to be stable inside the eye. If your visual demands are high and you like the idea of a procedure that is reversible, and if cost is not an issue (ICLs can cost three to four times as much as LASIK), then an implantable lens may be the way to go. ICLs can be used for treating long-sightedness, but are not available for use locally.

 Suitability

In order to be suitable for LASIK or ASA, you need to satisfy the following criteria:

– Be above 18 years of age

– Have a stable degree of correction for at least six months

– Not pregnant or breastfeeding if you are female (Pregnancy and breastfeeding can cause fluctuations in spectacle degree.)

– Be otherwise healthy (If you have a medical condition, your condition should be well-controlled and stable.)

– Have healthy eyes which have sufficient cornea thickness for sculpting by the laser

– Not have eyes which suffer from significant dryness

Safety and Adverse Effects

As with all surgeries, refractive surgeries can have a downside.  Dry eyes, glare, and halos around lights at night are some of the more commonly experienced side effects of surgery. These symptoms tend to improve with time, but one must be able to adapt to any persistent side effects that remain.

More seriously, patients must be aware that although complications are rare and take place less than 1% of the time, they must be willing to accept the risk before undergoing refractive surgery. Some complications include infection and ectasia (a permanent weakening of the cornea which may require subsequent treatment and surgery), as well as LASIK flap-related problems.

ASA has an additional risk of scarring known as haze due to vigorous healing of the surgery site and can cause blurring of vision. But the judicious use of anti-scarring medication has markedly reduced the incidence of this problem.

The main adverse effect of ICL surgery is the risk of cataract formation if the implant is sized wrongly and rubs against the natural lens. However, with modern sizing technology including the use of ultrasound to visualise the internal eye, measurements are now more accurate and premature cataract formation largely avoided.

Conclusion    

If you are looking for a surgical answer for vision correction, then the most important thing for you is to get a thorough check-up to determine suitability and discuss your needs and expectations with your eye surgeon. Remember, LASIK and other forms of refractive surgery can potentially give you very good results and satisfaction, but none of these are perfect and you need to be willing to adapt to some of the changes together with the benefits they will bring to your life.

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Dr Gerard Nah is the Medical Director of W Eye Clinic.
Posted by ezyhealth on Jun 10 2014. Filed under Eye Health. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.

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