Light plays a big role in our society. Human activity and productivity relies largely on the presence of light. Lack of light or exposure to the brightness of the sun triggers a disposition that causes serious changes in a person’s way of life, and consequently, on his health. Less sunlight, rather than lowered temperatures, becomes reason enough for certain people to sink into a depression. Cases that reach a critical level may even lead to hospitalization.

When the winter season kicks in, the amount of natural light that people are exposed to decreases significantly. While there may be some who revel in bringing out and wearing the latest winter fashion, others react negatively to the change in climate. These people become vulnerable to feeling extremely lethargic and unproductive. All types of activity in an individual’s day-to-day routine are affected by the gloom brought about by the winter. This condition is commonly known as the “winter blues” or in medical terms, seasonal affective disorder (SAD).

A number of symptoms help determine whether an individual is suffering from SAD. The disorder attacks a person’s behaviour, health, mental condition and sleeping patterns. For instance, even if one gets enough hours of sleep, he still feels tired upon waking up. Catnaps are also necessary to try and alleviate the exhaustion. There are joint and stomach pains, weight and appetite increases, and high susceptibility to infections. Constant irritability, crankiness and sadness creep into the person’s temperament. Similarly, there exists a lack of conviction about almost everything, as well as emanating feelings of hopelessness or despair, anxiety and guilt. Focus, likewise, becomes difficult to achieve when performing tasks.

SAD usually resurfaces at the same time every year, usually in areas further away from the equator. People suffering from this condition experience depression from the winter months until springtime arrives. However, there have been a few reported cases of SAD during summer. Before a person is confirmed to have SAD, they must have experienced the symptoms of depression and gone into remission for at least two years in a row.

For this reason, the need to come up with measures to eliminate the number of SAD occurrences has created a challenge for product developers. Since the disorder is attributed to the lack of exposure to ample bright sunlight during winter and rainy days, a variety of daylight lamps or portable light boxes have been designed to compensate for the deficiency in natural light.

There are different types of daylight lamps. Some can be placed on desktops while others can be situated on the floor, lending more height for overhead lighting. There are also clip on lights that can be used for various art, collectibles and jewellery displays, cosmetics and graphics. There are also fluorescent bulbs, or full spectrum daylight tubes, with sizes including 24”, 48”, 60” and 72”, which are used to establish well-lit environments in offices, hospitals, schools, banks and other indoor facilities.

Daylight lamps mimic sunlight or natural outdoor light. This makes books, documents and other written or printed material easier to read by improving contrast. Crafting, needlework, sewing, photography and other hobbies that require attention to the tiniest detail, likewise become easier with this type of lighting. Working becomes easier and less strenuous on the eyes due to the absence of flickering and increased contrast. More importantly, having the quality of light coming from these indoor daylight lamps reduces the negative effects on productivity when one peer out the window and sees the change in natural outdoor lighting.

This quality of light emitted by daylight lamps may be measured with the symbol K, which pertains to Kelvin. This refers to the temperature or energy given off by a light source. Bulbs that provide a light intensity of 4700 Kelvin are best suited for reading and colour matching. Lower Kelvin measurements give off softer levels of light, for use in other activities.

In the same way, bulbs that possess a high colour rendering index or CRI are able to simulate the real colours of the object as accurately as possible. On one hand, a CRI of 100 would mean that the colours seen under the light are relatively the same to its true colour. Outdoor light registers with a CRI of 100. On the other hand, a CRI of zero would mean that the bulb or artificial light source gives off a poor rendition of the object’s real colours.

Aside from being used for normal activities, daylight lamps and light boxes also serve as a therapeutic tool for those with SAD. It is recommended that the person experiencing SAD sit close to the light box, which is made up of a number of fluorescent bulbs and a diffusing screen. The box is portable and can be set up anywhere in the home or office, usually on a desktop.

People getting light therapy treatment should not look directly at the bulbs. Rather, they are advised to continue doing activities such as writing, typing, reading or eating, while maintaining close proximity to the light box or daylight lamp. The head and the body should also be leaning toward the light. Length of the treatment may vary from fifteen minutes to as long as an hour, once or twice a day for the duration of the winter season, in order to gain the full effects of the therapy session.