vision conditions


Symptoms of astigmatism are headaches, eyestrain, squinting, and problems adapting to a spectacle prescription because of spatial distortion. This distortion may cause poles, walls and floors to looks warped and/or tilted. These symptoms generally go away when a patient adapts to his/her prescription in days to weeks.


Amblyopia or "lazy eye" describes weak vision or vision loss in one eye that cannot be fully corrected with lenses.

It usually develops in children before age eight. This is also the key time to treat amblyopia, since results are better the earlier they are implemented. It becomes extremely difficult to treat amblyopia after age eight. Untreated, amblyopia can lead to total blindness in the affected eye. This is one of the reasons the Canadian Association of Optometrists recommends all children get a full eye exam by 6 months of age to rule out conditions like amblyopia.

Amblyopia is more than simply an eye health problem. It involves the "wiring" of the nerve impulses from the eyes to the brain. Treatment typically includes vision therapy, eyeglasses and contact lenses, or a patch. Surgery alone cannot treat amblyopia.

Farsightedness (hyperopia)

Hyperopia, or farsightedness, is a common refractive error. Approximately 25 per cent of the general population may be affected. Vision is frequently unaffected in low amounts of hyperopia, but patients are often uncomfortable with this condition because of the increased effort needed to see clearly at near. With high amounts of hyperopia, vision gets poor especially when the patient tries to view near objects.

Farsighted individuals see better in the distance than up close because the eye does not effectively focus light. Farsightedness is very common among elementary school-age children and a frequent cause of reading and learning difficulties.

Refractive errors such as hyperopia are commonly corrected by eyeglasses or contact lenses. Refractive surgery is another possibility.

Nearsightedness (myopia)

Myopia, more popularly known as nearsightedness, is a common refractive error. Approximately a quarter of the general population may be affected. Children with myopia are often unaware of difficulty in distance viewing until they compare what they see with one of their friends or classmates. Myopic individuals see better up close than in the distance. This is because the eye improperly focuses too much light, causing blurred vision in the distance.

Refractive errors are commonly corrected by eyeglasses or contact lenses. Refractive surgery and Ortho-Keratology are two other possibilities.


Presbyopia literally means "old eyes". It first occurs at different times according to the occupation, hobby, etc. of the person. Someone reading at 25 cm will need bifocals sooner than someone reading at 40 cm. Common symptoms are blurry vision at near or an increased working distance for clear near vision.

Presbyopia is an inevitable condition in which the ability to focus on close objects decreases over time. Since it is a natural effect of aging, it is extremely commonplace. In recent years, an estimated four million new cases of presbyopia have been diagnosed. Today's "baby boomer" generation is the most rapidly growing population segment requiring vision correction.

Symptoms: Headaches, blurred near-distance vision, tearing, stinging, or a need for more light. People with presbyopia often hold reading material at arm's length.

Treatment: Reading glasses (typically bifocals) or special contact lenses are useful treatments, although the period of adjustment can vary widely. All told, there is a wide range of corrective options to review with your Optometrist.

Prevention:There is no recognized prevention available, although focusing difficulties can be relieved with corrective lenses.

Further questions: For such a common condition, there are many misconceptions about presbyopia. For example, it does not affect a person's lifestyle, but presbyopia can require frequent prescription changes after age 40.

Strabismus (crossed eyes)

Strabismus or "crossed eyes" is a misalignment of the eyes. One or both eyes may turn in (esotropia), out (exotropia), up (hypertropia) or down (hypotropia). Treatment may include the use of eyeglasses, contact lenses, prisms and/or vision therapy. In extreme cases, surgery may be needed.

Color Deficiency

Color vision deficiency means that your ability to distinguish some colors and shades is less than normal. It occurs when the color-sensitive cone cells in your eyes do not properly pick up or send the proper color signals to your brain. About eight percent of men and one percent of women are color deficient.

Red-green deficiency is by far the most common form and it results in the inability to distinguish certain shades of red and green. Those with a less common type have difficulty distinguishing blue and yellow. In very rare cases, color deficiency exists to an extent that no colors can be detected, only shades of black, white and grey.

All content is provided for education and information, and is no substitute for the advice of your optometrist. Most of this information is provided courtesy of the British Columbia Association of Optometrists (B.C.A.O.) and the book Refractive Management of Ametropia by Kenneth E. Bookman.