What is 20/20 Vision?
20/20 vision refers to the clarity of vision when looking at something that is 20 feet away, or the amount of detail that can be seen from 20 feet away. If you need to be 20 feet away to read what most people can read at 40 feet, then your vision is 20/40. If you can see at 20 feet what most people can see at 15 feet, then your vision is 20/15.

20/20 vision is considered to be 'normal' and yet only 4 out of 10 people can see 20/20 without corrective lenses. However, most people can see 20/20 when wearing the proper corrective lenses for their eyes.

A person whose best vision with the proper corrective lenses is 20/200 or worse is considered to be legally blind even though they have some vision.

Occasionally you may hear a reference to 6/6 vision. This is simply the metric version of 20/20 vision because 20 feet are equal to 6 meters.

What do I need to know about sunglasses?
Sunglasses serve two very important purposes. They are designed to protect by blocking ultraviolet radiation (UV) from reaching your eyes. They are also used for comfort by decreasing glare.

UV is harmful to the eye and the dosages are cumulative over the course of a lifetime. Children are most at risk because during the first ten years of life the lens in the eye does not block as much ultraviolet radiation as an adult lens.

UV exposure can cause a sunburned cornea, cataract, damage to the front surface of the eye, skin cancer of the eyelids and damage to the retina (where light is focussed to form Images). UV exposure is one of the primary causes of macular degeneration. Macular degeneration is the leading cause of blindness in people over the age of 60 in North America.

Since UV is invisible, it's difficult to judge your exposure based on the brightness of the sunlight or the heat it generates. The sun's heat comes from infrared radiation, which is filtered by clouds. But clouds don't reduce the UV and therefore you are still being exposed.

Clear prescription spectacle lenses can be made to block all UV by applying a clear coating. Patients wanting extra protection from glare can wear lenses with various coats or tints.

Non-prescription sunglasses should meet the industry standard for blocking UV. A wrap-around style and making sure the lenses fit close to the eyes will help to minimize exposure. Wide-brimmed hats help to block exposure to overhead UV and may be particularly helpful for infants who just won't keep their sunglasses on, however, hats are not asubstitute for sunglasses.

The key lesson is that, since UV dosage is cumulative, protection should begin as early as possible and be as complete as possible. For those at greater risk such as young children, outdoor workers and skiers, the message is all the more urgent.

When should I have my eyes examined?
Visiting your optometrist for regular eye exams is an important part of preventative health care. There are many vision and health conditions that do not have obvious symptoms and yet early diagnosis and treatment are key factors in a good prognosis.

Infants and Toddlers
Newborns are often evaluated for congenital eye diseases before release from the hospital. The first evaluation by your optometrist is usually recommended at 6 months of age, or sooner if abnormalities are noticed, or one parent has an eye disorder that is hereditary.

Further eye exams at 3 years of age and just before entering school will provide evaluations of the child's visual development and allow for early treatment if it is necessary.

School Children
The frequency of examinations needed by school children is related to the information found in previous exams. Most children can be examined every year unless they show difficulty reading books, seeing the blackboard or complain about sore eyes. A child with nearsightedness may need to be examined more often if their prescription is changing.

Adults
Most adults require periodic eye examinations every two years. While the presence of eye disease is not common in young adults, eye strain due to visual demands is prevalent and can often be treated by your optometrist.

Around the age of 45 years adults begin to have trouble seeing close objects. This is called presbyopia and it is a normal aging change. Your optometrist can prescribe different types of corrective lenses to allow you to see clearly up close. Presbyopia progresses gradually for about 10 years and requires periodic eye exams to modify your prescription.

Older Adults
Adults over 65 years of age are at increased risk of eye disease and may require additional aids for optimal visual performance. For these reasons annual eye examinations are recommended.

Why do children need eye examinations?
Visiting your optometrist for regular eye exams is an important part of preventative health care. There are many vision and health conditions that do not have obvious symptoms and yet early diagnosis and treatment are key factors in a good prognosis.

There are many conditions that may prevent a child from seeing clearly out of one eye and yet they have no symptoms of poor vision because the other eye sees clearly. When this situation is allowed to persist the visual connections between the unused eye and the brain do not develop properly. This condition is called amblyopia and the vision is not restored later with spectacles (eyeglasses). Early diagnosis of the conditions which result in amblyopia can prevent its development. Even early diagnosis of the presence of amblyopia improves the prognosis for treatment.

Children generally do not report symptoms of poor vision as they have no way of knowing what clear vision should be like. If a child is very farsighted (hyperopic) they will find near work such as reading and colouring to be very difficult and tiring. A child who is nearsighted may not be able to see the blackboard at school. Spectacles (eyeglasses) can be used to correct these vision problems.

Your optometrist can test for colour vision deficiencies which are more common in boys than girls. Your optometrist can explain to you and to your child's teacher how the colour vision deficiency will affect performance in art classes, reading colour coded maps and future job restrictions.

Children who were born prematurely or with low birth weight are at particularly high risk for developing eye and vision problems. A family history of high refractive error, crossed eyes, or congenital eye disorders also increases a child's risk for developing the same condition.