The most common vision problems are refractive errors, which occur when the shape of the eye prevents light from focusing directly on the retina. The length of the eyeball (either longer or shorter), changes in the shape of the cornea, or aging of the lens can cause refractive errors. Most people have one or more of these conditions.

Vision occurs when light rays are bent (refracted) as they pass through the cornea and the lens. The light is then focused on the retina. The retina converts the light-rays into messages that are sent through the optic nerve to the brain. The brain interprets these messages into the images we see.

The most common types of refractive errors are near-sightedness, far-sightedness, astigmatism and presbyopia.

Near-sightedness (or myopia) is a condition where objects up close appear clearly, while objects far away appear blurry. With near-sightedness, light comes to focus in front of the retina instead of on the retina.

Far-sightedness (or hyperopia) is a common type of refractive error where distant objects may be seen more clearly than objects that are near. However, people experience far-sightedness differently. Some people may not notice any problems with their vision, especially when they are young. For people with significant far-sightedness, vision can be blurry for objects at any distance, near or far.

Astigmatisms a condition in which the eye does not focus light evenly onto the retina, the light-sensitive tissue at the back of the eye. This can cause images to appear blurry and stretched out.
Presbyopia is an age-related condition in which the ability to focus up close becomes more difficult. As the eye ages, the lens can no longer change shape enough to allow the eye to focus close objects clearly.

The most common signs and symptoms of refractive errors are blurred vision, but other symptoms can include double vision, haziness, glare or halos around bright lights, squinting, headaches and eye strain.

An eye care professional can diagnose refractive errors or other eye problems during a comprehensive dilated eye examination. People with a refractive error often visit their eye care professional with complaints of visual discomfort or blurred vision. However, some people don’t know they aren’t seeing as clearly as they could. Refractive errors can be corrected with eyeglasses, contact lenses, or surgery.

Creative Commons License photo credit: See-ming Lee 李思明 SML

Most of us will experience temporary eye problems from time to time, including itching, blurriness or fatigue. Most of these eye problems are short-lived and will probably go away on their own with no complications. However, sudden eye problems and those that last for more than a couple of days should be checked by an eye doctor.

Eye twitching, eyelid ticks and spasms are pretty common. Most eye twitches come and go, although they can last for weeks or even months. Although sudden-onset eyelid twitching is benign, it can also be difficult to treat. The only option for making it stop is finding the cause and removing it. Some of the triggers for eye twitching include stress, tiredness, eye strain, caffeine, alcohol, dry eyes, nutritional imbalances and allergies.

Itchy eyes are often a symptom of allergies that are either seasonal or perennial. Itchy eyes will be triggered by exposure to things like grass, pollen, trees and weeds or to household allergens like mould, dust, pet dander and pet hair. The best treatment is to keep your hands away from your eyes so you don’t damage them from rubbing or scratching and to visit your eye doctor to discuss the best decongestant or oral antihistamines.

When the eyes feel achy, weak or heavy due to intense or overuse then you probably have tired eyes or eye strain. Eyes can be strained by working on the computer for too long, doing near work with poor lighting conditions or prolonging any activity that requires intense focus. To avoid tired eyes you should make sure your room is evenly lit, take short breaks from near work and ensure that your glasses or contact lenses are up to date.

Eye floaters are those tiny spots, specks, flecks and “cobwebs” that drift aimlessly around in your field of vision. They typically appear when tiny pieces of the eye’s gel-like vitreous break loose in the back portion of the eye. While annoying, ordinary eye floaters and spots are common eye problems, but not usually cause for alarm. However, if you experience a sudden appearance of lots of floaters, especially accompanied by flashes of light, then you should seek medical attention immediately as this could indicate a detached retina.