It is essential that the visually impaired ensure they create optimum lighting conditions wherever they are in order to maximize their vision. A good light source can make a dramatic difference to everyday tasks such as reading, writing, food preparation and choosing clothes. Good quality light will help you improve your independence and maintain your personal safety.
There are two types of artificial light:
A. Simulated daylight light
B. Traditional artificial light
The following diagram shows the differences between simulated daylight and normal artificial light:
The best type of light for low vision is simulated daylight light. This recreated clean crisp light provides relaxing and healthy lighting conditions for your eyes. This type of light delivers all the high quality lighting options needed by partially sighted people.
Advantages of simulated daylight bulbs and tubes:
• Increases contrast
• Increases clarity
• Reduces glare
• Most environmentally friendly (low energy)
• Safest light for partially sighted people (low heat)
• Most comfortable light for your eyes
The most common artificial light comes from filament light bulbs. These are usually balloon-shaped with wires inside. The brightness of these bulbs depends on the number of watts they use. This type of widely used reading light has a yellow tinge that can distort contrast and colors and produce glare. Traditional artificial light is not recommended for blind or partially sighted people.
Adjustable task lamps are particularly useful for reading because you can point them to make the light fall directly onto what you want to see. Adjustable lamps can be floor or desk standing and they have a base or bracket to which an adjustable arm and a flexible head are attached. The best position for an adjustable lamp is between you and what you want to look at; aimed at the subject, below your eye level.
How We Use Our Eyes To See
Seeing can be likened to the process of taking pictures on a film with a camera which you then get developed. The retina is like a camera film which stores an image of what we are looking at. The image directed onto the retina is then sent along to the brain where it is processed, like developing a camera film. Therefore we actually ‘see’ in our brain with the light information sent to it from our eyes.
This whole process happens very quickly so that everything we see is in focus.
Why is light important to vision?
Our eyes need light to work. Light entering the eye is collected by the retina and processed by the brain to obtain the pictures that we need to see. Light is an essential part of this process, for example it is difficult to read when light levels are low. Sometimes light can cause problems for our vision.
What are the problems with light that can occur?
There are times when the amount of light or the quality of that light can affect our ability to see. Many people with low vision need more light than usual to read. However, too much light can cause problems from glare.
To summarize there are many products to help overcome partial sight loss from contact lenses to massive magnification instruments. However, experts are in agreement that the easiest and most effective aid to improving sight for all of us is simply good quality light.
Lighting technology explained
The best way to explain in technical terms the differences in light is with the light measurement ‘Temperature Kelvin’ (°K) – which is, in a nutshell, the color of the light. The color variation is referred to as the color temperature and is measured in degrees Kelvin. The scale ranges from the color of a candle flame at around 2000°K to a deep blue-sky color at around 10,000°K. The color of ‘average noon light’ (5,000°K – 6,500 °K) is white and under this white colored light white objects appear whiter and all other colors appear most natural. This is the case for every day objects and images and so helps those with low vision to see more clearly.
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