Presentation on theme: "Environmental Optometry Faculty of optometry Diana Alrabi."— Presentation transcript:
Environmental Optometry Faculty of optometry Diana Alrabi
Lighting or illumination is the purposeful application of light to achieve some practical or visual effect. Lighting includes the use of both artificial light sources such as lamps and light fixtures, as well as natural illumination by capturing daylight. Day lighting (using windows, skylights, or light shelves) is often used as the main source of light during daytime in buildings. This can save energy compared with artificial lighting, which represents a major component of energy consumption in buildings. Without proper design, energy can be wasted by using too much light, or using out-dated technology.
Proper lighting can enhance task performance, improve the appearance of an area, and have positive psychological effects on occupants. One of the central dogmas of proper lighting is that a uniform illumination is required in many applications, such as projection displays, LCD backlights, medical lighting, microscopy, solid-state lighting, and general lighting It is essential that the visually impaired ensure they create optimum lighting conditions wherever they are in order to maximise their vision. Lighting is a crucial issue if you experience sight loss, at home and away. 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. Why is light so important?
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 the ability to see. Many people with low vision need more light than usual to read. However, too much light can cause problems from glare 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.
What is the best type of light There are two types of artificial light: A.Traditional artificial light The most commonly used bulbs are filament light bulbs. These are usually balloon-shaped with wires inside. The brightness of these bulbs depends on the number of watts they have. The higher the number of watts, the brighter the bulb will be. This type of widely used light has a yellow tinge which can distort contrast and colors and produce glare. This light source is not recommended for partially sighted people.
B. Simulated daylight light This recreated clean crisp light provides relaxing and healthy lighting conditions for the eyes. It increases contrast and clarity and reduces glare. This type of light delivers all the high quality lighting options needed by partially sighted people.
Lighting is classified by intended use as general, accent, or task lighting, depending largely on the distribution of the light produced by the fixture Task lighting is mainly functional and is usually the most concentrated, for purposes such as reading or inspection of materials. For example, reading poor-quality reproductions may require task lighting levels up to 1500 lux (150footcandles), and some inspection tasks or surgical procedures require even higher levels
Accent lighting is mainly decorative, intended to highlight pictures, plants or other elements of interior design or landscaping. General lighting fills in between the two and is intended for general illumination of an area. Indoors, this would be a basic lamp on a table or floor, or a fixture on the ceiling. Outdoors, general lighting for a parking lot may be as low as lux (1-2 footcandles) since pedestrians and motorists already used to the dark will need little light for crossing the area.
What kind of light is best? Bright light is critical for the success of the Body Blues Program. It enhances your mood, reduces your food cravings, and gives you more energy. It even increases the blood flow to your brain, improving your memory and sharpening your thinking ability. But there is a lot of confusion about which kind of light is best. Visitors to this site have asked: "Does it have to be natural light?" "Do full-spectrum lights such as the OTT light offer special advantages?" "Which do you recommend— ordinary bulbs or fluorescent lights?" "Can I get a "high" from a tanning bed?" "Does UV light influence your mood?" "Is there a best time of the day to get bright light?" "Does light have to come through your eyes in order to boost your mood?" "Can I get too much light?". Time for some answers.
First, the basics. Light boosts your mood in two fundamental and quite different ways: 1) by falling on your bare skin, or 2) by entering your eyes. Only one type of light influences your mood through skin exposure—ultraviolet or UV light. When UV light interacts with your skin, it triggers the formation of vitamin D. Vitamin D is far more than a bone builder. It has widespread influence throughout your body, including stimulating the production of feel- good brain chemicals such as serotonin and dopamine.
Unfortunately, UV light, whether from the sun or from artificial light sources, also promotes skin aging and increases your risk of skin cancer. Another way to get vitamin D is to drink fortified dairy products or take vitamin D supplements. Do the supplements offer the same mood benefits as the sun? Yes, according to researcher Allan Lansdowne who gave either placebos or vitamin D to volunteers who had low body stores of Vitamin D. At the end of the study, those who had been given the placebos had little change in mood. Meanwhile, those who had taken the vitamin D supplements felt noticeably better. In fact, many reported a better mood during the very first days of the study. The light that enters your eyes has an even more immediate effect on your mood. Within 30 minutes of being in a very bright environment, you will feel more energetic and light-hearted. You will think more clearly and have a faster reaction time. After only a few days of these light treatments, you will be eating less and having fewer carbohydrate cravings. more outdoors, where the light levels range from 1,000 to 50,000 lux or more.
Light offers you all these benefits because it modulates the production of certain hormones and brain chemicals. To be specific, bright light shuts down the production of melatonin, the nighttime sleep hormone. It also stimulates the production of serotonin, its energizing, daytime counterpart. In fact, within a few hours, the amount of serotonin in your brain will reflect the amount of light in your environment. More light = more serotonin = more energy, a better mood, and fewer carbohydrate cravings. In essence, light is the environmental cue that switches your body from a slumbering to an energized mode. If you don't get enough light during the day—and most women don't—you are likely to feel sluggish, irritable, hungry, and half-asleep all day long—a.k.a. the Body Blues! How much light do you need to get rid of these unpleasant symptoms? More than you can get indoors with ordinary room lighting, which is about lux. (Lux is one way to measure light levels.) The simplest way to get enough bright light is to spend an hour a day or