Night Blindness
- Sunday, July 11, 2010, 14:59
- Health
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If you need a nightlight to find your way to the kitchen for a midnight nibble, or have complexity seeing while driving in the evening, you may be suffering from a state known as “night blindness.”
Unlike animals, human vision is usually not as keen at night. Cats, for instance, see well at night because they have more rods than cones in their retinas, unlike humans. (Rods are the receptors that the eye uses for nighttime vision.)
It is predictable that most people take about 20 minutes to see adequately in the dark. This time allows your eyes to adjust from the intensity of daylight or indoor lights. As the light dims, your pupils open (grow larger) to take in more light.
But your dilated pupils reduce your aptitude to change your focus between near and far objects, so if you are driving, say, you may be “blinded” by streetlights and approaching headlights. Your pupils constrict to block out the lights, but once those have approved, they must dilate to readjust to the dark, making it difficult to see the road.
Unlike a cat’s, human pupils simply can’t regulate fast enough to keep up with the cycle of light and dark.
One of the most common causes of night blindness is worsening due to age. In the natural aging process, the eye lenses becomes less clear and grow cloudy over time, making it difficult to see in dim light. It is estimated that senior need up to 50% more light to see clearly.
Another general cause is uncorrected myopia, or nearsightedness. Even with vision correction, shortsighted people may find their nearsightedness is exacerbating when their pupils dilate at night.
- Vitamin A supplements are often optional for those with poor night vision, along with a diet emphasizing Vitamin A-rich foods, such as sugary potatoes, carrots, mangoes, spinach and cantaloupe.
- Bilberry is also thought to get better night vision. A close relative of the blueberry, bilberry is high in a sure type of bioflavonoid that speeds the regeneration of rhodopsin, the purple pigment used by the eyes’ rods.
- Keep your car windshield and car windows clean-inside and out. Having grime and debris on your windshield makes it harder to see and exacerbate glare, particularly at night.
- The exercises in the Vision for Life agenda combat both aging vision and nearsightedness, thus helping with the root cause of night blindness. Within weeks, even days, you can start to see more clearly. Your night vision will be sharper your eyes will feel stronger.
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