Many reptiles need specialist lighting. This is usually provided using fluorescent strip bulbs designed specifically for reptiles that emit a form of ultraviolet light called UVB, the most popular brand in the UK being Exo Terra's Repti Glos though there are many other brands available varying in price. Pretty much any day active lizard will require this form of lighting. It is very important because day active reptiles synthesize a vitamin called D3 using UVB light. Vitamin D3 is an essential vitamin that allows reptiles to metabolize the calcium in their food. Without it, they can not metabolize the calcium regardless how much is in their diet and so they will suffer from a crippling condition known as Metabolic Bone Disease (MBD) which can result in severe skeletal deformities and in worse case scenarios, death.
Normal fluorescent lights do not emit UVB and nor do common ultraviolet lights like "black lights." Always use a light that is designed to be used for reptiles. These bulbs also emit visible light, however they will only emit UVB for a period of around 6 months so regardless of whether the bulb is still emitting visible light after this time it will need replacing.
For maximum effect, the bulb should ideally be no more than six to ten inches away from the reptile, though the range is effectively doubled if you use a reflector. Try to position the bulb and arrange the vivarium so that your reptile will spend a large part of the day within range of the bulb ie when basking.
There are several types of UVB emitting fluorescent bulb. Repti Glos come in three types: 2%, 5%, and 10%. The percentage refers to how much of the light's spectrum is in the UVB range. 5% and 10% are the most popular though are suited for different types of reptiles. 5% bulbs are usually used with Rainforest and European species since the intensity of the sunlight in these areas is relatively low. 10% bulbs are usually used for desert species that spend a large part of their lives in direct sunlight.
Nocturnal reptiles like Leopard Geckos do not require any specialist lighting as they rarely venture out in daylight.
Please fully research the requirements of the reptile you are interested in before deciding which lighting system is best suited for you.