What is Nearsightedness (Myopia)?
Nearsightedness or myopia, is the most common focusing problem in North America, affecting over 30% of the population. Nearsighted people can see things that are close, but they cannot see clearly in the distance. Nearsightedness usually results from an eye that is too long in relation to its focusing parts.
Because of this extra length, the lenses cannot focus the light rays from distant objects on the retina. Instead, the images focus in the centre cavity of the eye and then diverge into a blur by the time they reach the retina.
Most focusing problems like nearsightedness can be corrected with corrective lenses or refractive surgery.
What is Farsightedness (Hyperopia)?
Farsightedness or hyperopia, affects about 10% of the people in North America. Farsighted people may see things in the distance, with extra focusing effort, but they cannot see clearly up close, unless they are young and use additional effort. Farsightedness is a focusing problem usually resulting from an eye that is too short.
Because of the reduced length, the muscles adjusting the lens may fatigue, or the lens may not be able to respond enough to focus the light rays. The retina thus receives a blurred image of light. The noticeable effects of farsightedness increase with age as the inner lens loses its ability to vary its focus to compensate for the problem.
Most focusing problems like farsightedness can be corrected with corrective lenses or refractive surgery.
What is Astigmatism?
Astigmatism is a general inability of the eye to clearly focus images from any distance because of unequal curvatures of the cornea. Instead of being spherical, an astigmatic cornea has more curvature in one direction than another. It has two curvatures, similar to a football rather than a well-rounded basketball.
Nobody has a perfectly shaped cornea, but the distortion of most eyes is so slight that it does not significantly affect vision. However, more than a small degree of astigmatism can noticeably blur vision. Astigmatism can occur alone or along with nearsightedness or farsightedness.
Most focusing problems like astigmatism can be corrected with corrective lenses or refractive surgery.
What is Presbyopia? What is the need for reading glasses?
Presbyopia is a universal focusing problem developing in most people around 45 years of age. When eyes are young, the gel inside the internal natural lens is soft so it can change shape to allow people to focus on things at various distances. But as the eye ages, the gel hardens and the lens enlarges and loses its ability to change shape to focus on near objects. People with natural 20/20 distance vision will likely need reading glasses when presbyopia develops.
Proven correction procedures are not currently available to correct presbyopia directly. Even if you achieve excellent vision through surgery, reading glasses are usually necessary beyond 45 years of age. However, new types of surgery to correct presbyopia are being investigated and may be available at our Centres in the future.
What is a Cataract?
A cataract is a cloudiness that develops in the normally clear lens of the eye. For the sake of easy reference, a natural lens is referred to as a cataract when it has turned cloudy. A cataract is not a growth, a white film, or kind of cancer.
The lens is a transparent fine-focusing element suspended behind the pupil opening of the eye. It is about the size of an ordinary pill and consists of a strong, transparent outer capsule filled with a transparent flexible gel. As the lens varies its thickness, it enables the eye to focus on both near and far objects.
When light enters the eye, it passes through the cornea (the eye’s clear front window) and then through the pupil and the lens, which fine focuses the light rays onto the retina at the back of the eye. The retina changes the light images into electrical impulses and sends them to the brain via the optic nerve. When the lens has clouded over with the development of a cataract, light becomes distorted and is not focused clearly on the retina. Vision is reduced, and blindness can eventually result.
Almost everyone who lives a long life will develop cataracts. The cloudiness does not spread from one eye to the other, but cataracts will usually develop in both eyes at some time. Some cataracts mature slowly over a period of years, whereas others can form rapidly within a few months.
I asked to be referred to Dr. Gimbel for my cataract surgery because of his reputation and was more than pleased with the professionalism, the competency, the knowledge & advanced technology. I no longer have astigmatism with the new Toric lenses – I can see the world clearly now!
~ Marion B.