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What is Colour Blindness?

Colour blindness is a condition affecting one's ability to distinguish colours under normal lighting conditions or to perceive colours as they are normally viewed. Usually, the disorder is present at birth, but it can also be a result of injuries or a number of diseases of the eye.

Colour perception is dependent upon the cones located within the retina of the eye. Humans are commonly born with three types of cones, each perceiving different wavelengths of colour. With colours, the length of the wave is directly related to the perceived colour tone. Short waves project blue tones, medium-length waves project greens and long waves produce reds. Which pigmented cone is affected has an impact on the nature and seriousness of the colour blindness.

Being a sex-linked recessive trait, many more men are green-red colour blind than females. Nevertheless, there are plenty of women who do experience some degree of colour vision deficiency, specifically blue-yellow deficiencies.

There are many cases in which individuals develop colour vision problems later in life resulting from another condition including injuries, cataracts and especially macular degeneration. Thankfully, it might be possible to reverse the condition once the cause is treated

There are several tests for the condition. The most common is the Ishihara colour exam, called after its inventor. For this test a plate is shown with a group of dots in a circle in differing colours and sizes. Inside the circle one with proper colour vision can see a digit in a particular tint. The individual's ability to make out the digit within the dots of clashing tones examines the level of red-green colour vision.

While hereditary colour blindness can't be treated, there are a few options that can help to make up for it. For some, wearing tinted lenses or glasses which minimize glare can help people to perceive the distinction between colours. Increasingly, computer applications are on the market for standard personal computers and for mobile machines that can help users enhance colour distinction depending upon their particular condition. There are also exciting experiments being conducted in gene therapy to correct the ability to perceive colours.

The extent to which colour blindness limits an individual depends on the type and degree of the condition. Some individuals can accommodate to their deficiency by learning alternative clues for coloured objects or signs. For instance, some might familiarize themselves with the shape of traffic signs in place of recognizing red, or compare objects with reference objects like green trees or the blue sky.

If you notice signs that you or your loved one could be colour blind it's recommended to get tested by an optometrist. The sooner the condition is diagnosed, the sooner you can help. Feel free to call our Calgary, AB optometrists for more information about colour blindness.

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