Eye Care for Pilots
By Luzanne Keyter
Flying is an inherently visual activity and being able to see is a pilot's most important sense. Being able to clearly see your surroundings and take in information during flight is fundamental to safe and fun flying.
For pilots it is very important to know whether they have normal uncorrected vision, are nearsighted or farsighted or if they suffer from any other visual problems like Presbyopia, the age-related impaired focusing of near objects that starts after the age of 45 and that are present in 100% of people, even those with perfect vision in their younger years.
All pilots have to pass a visual examination to obtain their flight medical as required by the South African Civil Aviation Authority (SACAA). The minimum requirements differ depending on the class of medical you need. According to the SACAA you are allowed to fly with spectacles or contact lenses as prescribed by your optometrist. Refractive abnormalities of the eyes are allowed to be corrected through surgery but a 3 to 6 month waiting period is required before the pilot can be re-certified and be able to fly.
Self medicating, using alcohol and the effects of a hangover, smoking tobacco and the withdrawal thereof, low blood sugar levels and wearing inappropriate, bad quality sunglasses can seriously impair your vision.
According to Jannus van der Molen, a local optometrist, the sun is one of our biggest enemies of good vision in the cockpit as it causes glare and adverse lighting causing uncomfortable or unclear vision. Thus, wearing high quality sunglasses can greatly improve your comfort and safety while flying. "Good sunglasses fit well, had an anti-glare coating on the inner surface to keep light from reflecting off it and the lens is distortion free," van der Molen said and added that these qualities can only be found in reputable brands preferably dispensed by trained optometrists.
Sleep deprivation or fatigue can cause sight problems, including the inability to focus. According to United Stats of America's Federal Aviation Administration's 'Pilot Vision' document, the most common symptoms of visual fatigue include blurred vision, excessive tearing, heavy eyelids, headaches and burning, scratchy and dry eyes.
A colour blindness test is another very important part of any visual examination. Medically referred to as colour vision deficiency, it is in most cases caused by a congenital disease based on a corrupted chromosome. Affecting more men than women, the fault lies within the different sells in the back of the eye that detects colour. Contrasting to popular belief, a lot of people suffering from colour blindness can see a variety of colours, most only suffering from red-green colour blindness where blue, green, red and purple will be perceived as gray.
So far there is no cure for colour vision deficiency, but colour correcting lenses may be the answer to improve colour vision. Using two differently coloured lenses you can party shift your perceived colour spectrum and thus see more colours. Sadly, by using this method you will also loose some colours that were previously visible and the product has only been launched in the USA and it is still undergoing studies.
In South Africa the Ishihara colour blindness test is most commonly used during visual examinations for pilot flight medicals. Named after Dr. Shinobu Ishihara, a professor at the University of Tokyo, the Ishihara test is specifically used to test for red-green colour blindness.
Being able to differentiate between different colours is important for pilots for a variety of reasons. Instruments and warning systems use colour to convey information to the pilot. Navigation lights on aeroplanes are used to determine the direction the aircraft is moving in. A red light is always on the left (Port) side of an aircraft and a green light on the right (Starboard). For pilots flying during the night it is essential to be able to differentiate between the two colours in order to derive the direction and tell if an aeroplane is coming or going.
According to van der Molen the best method to look after your eyes is to wear proper sunglasses. "It protects your eyes from harmful UV rays that cause cataracts and macular degeneration." Annual eye exams are very important as they can reveal anything out of the ordinary soon enough to treat successfully. In terms of diet, he strongly recommends green vegetables, anything high in antioxidants and of course, carrots!
Looking after you eye health, wearing the right kind of glasses, sunglasses and contact lenses and visiting your local optometrist regularly will help you keep your sight healthy and enjoy your passion for flying and aviation for a longer time.
Jannus van der Molen regards himself as a trained optometrist but a pilot by birth. For any enquiries, for more information or to book your annual eye examination, contact him at Eye Level Cradlestone Mall on (010) 003 6699.
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