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Understanding Visual Acuity

eyechart2You have most likely come across the terms 20/20 vision and visual acuity. But what do these terms really mean? Understanding them will give you insight into how your optometrist assesses your eyes during your eye exam.
20/20 vision is used to indicate the clarity and sharpness of your vision measured at a distance of 20 feet. If you have 20/20 vision, you can see clearly at 20 feet what is normally seen at that distance. If you have 20/100 vision, it means that you need to  be as close as 20 feet to see what a person with normal vision can see at 100 feet. Did you know that 20/20 is just a standard? Many people can actually see better than 20/20, for example 20/15.  

Each eye is tested separately. When you're asked to read the letters on the eye chart during your eye exam, the smallest row that you are able to read accurately indicates your visual acuity in the eye that is being tested.

20/20 vision doesn't necessarily mean your vision is perfect as it only indicates the sharpness or clarity of vision at a distance. Other important vision skills, such as the ability to bring close objects into focus, contrast sensitivity, peripheral awareness (side vision), depth perception, focusing ability, eye coordination and color vision contribute to your overall ability to see.   Also a person that has 20/20 vision may still have unhealthy eyes. People that have  damage to the sensory nerves within your eyes (the retina) from glaucoma, diabetes, high blood pressure, or other diseases can still obtain 20/20 vision without glasses. This is why your optometrist always performs a comprehensive eye exam, rather than just a simple vision test.

So the next time you have a comprehensive eye exam, you'll be able to understand why we ask you to read the letters on the chart in front of you and more!

Thank you for trusting your eyecare with us over the years.  The Foresight Eyecare team follows the government mandate to reduce the spread of the COVID-19 pandemic.  After December 2020 announcements made by the Alberta Government, our clinic is following the revised Infection Prevention and Control policy by the Alberta College of Optometrists.

Patients interested in obtaining eye exam services or eye care products can be seen by appointment only.  Please call ahead, and staff will arrange an appointment time and ask COVID-19 screening questions.  If you have any symptoms of cough, fever, runny nose or shortness of breath, we ask that you call or e-mail us and do not attend the clinic for your scheduled visit.   Within the clinic, please wear a mask and use the hand sanitizer at reception.  Our clinic complies with the City of Calgary bylaw requiring mask covering over the age of two years old.  For patients who are unable to wear a face covering due to medical reasons, the patient can be scheduled for an appointment at a time when minimal number of other patients are in the clinic such as at the beginning or end of the day to ensure appropriate physical distancing requirements.

We are using disposable disinfectant wipes on all surfaces and devices such as front desk counters, chairs, handles in exam rooms and waiting room.  All eyewear that have been touched by patients are continually being sanitized.   Any toys and magazines are stored at this time.  Examination areas are being sanitized with hospital grade disinfectant.  Debit and credit cards but NO CASH payments will be accepted.

COVID-19 symptoms are not always obvious.  We want to fend off this pandemic and minimize risk to our patients and the Foresight staff as front line health workers.   Contact that is closer than 2 m (6 feet) is to be avoided, with barriers in place when this cannot be avoided. We choose to continue to do our work and cautiously take care of our patients with compassion, humility, gentleness, and patience.   It is a challenging and new experience for many of us, so let‘s support each other and prevent virus spread!  Beyond 2020, our focus is on take care of you and keeping Clean Hands, Clear Heads and Open Hearts.   For more information, please refer to the following web pages or phone Health Link 811.

Drs. Dianna Leong, Anh Bui, Andrew Chan