Ali Mearza answers some of the most frequently answered questions about laser eye surgery and the various reasons for not having 20/20 vision.
What is the difference between short-sightedness and long-sightedness?
In short-sightedness (also known as myopia), light is focused in front of the retina and as a result we can see things close up but not far away. This is because the focusing power of the eye is too strong or the eyeball is too long or a combination of the two. As such, negative power lenses are used to weaken the focusing power and correct the problem. In long-sightedness (also known as hyperopia), the reverse is true in that the eye ball is either too short or the focusing power is not strong enough so images are focused behind the retina. Plus power lenses are then required to correct this.
What is astigmatism?
Astigmatism is where the cornea (front window) of the eye is not perfectly spherical; it is the shape of a rugby ball as opposed to a football. This causes the images being seen to be focused at two points instead of one resulting in a blurred image. The most common symptoms caused by astigmatism include squinting, headaches and eye strain. It develops early in life and can be detected in a routine eye exam, it can be corrected by glasses, contact lenses or laser eye surgery.
What causes eyesight problems (e.g. short-sightedness, long-sightedness, astigmatism)?
Short-sightedness and long-sightedness are both caused by the shape of your eye ball. If your eyeball is too short in relation to your cornea the image is focused behind the retina resulting in long-sightedness. If your eyeball is too long, the image is focused in front of the retina leaving you short-sighted. Astigmatism is where the front of the eye is not round, like a football, instead slightly elongated similar to a rugby ball shape. This causes the image to be focused at two different points instead of one resulting in blurred vision. Astigmatism can occur with both short and long-sightedness.
Can eyesight problems get worse over time?
Typically, the degree of short-sightedness or long-sightedness as well as astigmatism tends to stabilize by the age of 21. In some individuals, changes can occur up to the age of 30. If considering laser eye surgery, it is important that the prescription in your eyes has been stable to lower the chances of a re-treatment or enhancement procedure being required.
What is the difference between these problems and age-related sight problems?
Eyes age with the rest of our bodies, the natural lens in the eye become less elastic and flexible and most people find they struggle to focus on near objects; the technical name for this is presbyopia. This is why most people need reading glasses when they get older. Another age-related problem is the development of cataracts. A cataract is when the natural lens of your eye becomes clouded, this clouding does get worse over time and causes your eyesight to decrease.
What are my options for overcoming sight problems?
Depending on the problem with your sight, there may be a number of options available to you. Being long or short sighted or having astigmatism can be remedied by the daily use of glasses or contact lenses. Alternatively, laser eye surgery or refractive lens exchange could be an option depending on age and preference for those individuals who wish to reduce their dependence on glasses. In the case of cataracts this can only be cured by an operation replacing the clouded lens with an artificial one.
How does laser eye surgery work?
There are two types of laser eye surgery, LASIK and LASEK. LASIK works by using a laser to create a flap in your cornea (the front window of your eye) and then another laser to reshape your cornea. Reshaping your cornea will change the way light enters the eye ensuring it focuses directly on the retina instead of in front or behind it. LASEK is similar but the difference is that there is no flap. Instead, an alcohol solution is used to remove the outer layer of cells of the cornea, a laser is then used to reshape the cornea in the same way as LASIK and then the outer layer regenerates over a period of three to four days.
Does it take a long time to recover from laser eye surgery?
LASIK has a quicker recovery period compared to LASEK. For LASIK we see you the day following your surgery and a week later. In most cases people are fine to go back to work and normal life 2 days after surgery. With LASEK we put a protective lens over the cornea after the operation, we remove this three to four days after the surgery. After the lens has been removed, most people will be fine to go back to work. You are given eye drops to aid the recovery of your eyes and for such a life changing operation it has a very quick recovery time!
Is laser eye surgery permanent?
Laser eye surgery will correct your vision permanently until your eyes start to age. The laser cannot prevent aging of the eyes so it is common for people to find they start to need reading glasses from the age of 45 onwards. As you get older and your lenses become less elastic, most people struggle to see things close to them. At this stage, most people are happy to use reading glasses as and when they need them, but others do opt for another surgical procedure to correct this. Laser can be used to address this by making one of the eyes slightly short sighted and the other option is refractive lens exchange with multifocal lens implants.