Photochromic lenses such as those made by Transitions Optical are clear (or nearly clear) indoors and darken automatically in response to sunlight outdoors. They also protect your eyes from 100 percent of the sun's harmful ultraviolet radiation.
Anti-reflective coating (also called AR coating or anti-glare coating) improves both your vision through your lenses and the appearance of your eyeglasses. Both benefits are due to AR coating's ability to eliminate reflections of light from the front and back surface of eyeglass lenses. AR coating is especially beneficial when used on high-index lenses, which reflect more light than regular plastic lenses. Generally, the higher the index of refraction of the lens material, the more light that will be reflected from the surface of the lenses.
It depends on your own choice and usage of your glasses. If you new glasses are usually used for computer use and night driving, you'd better choose anti-glare coatings. If you want to change the color of lenses on your glasses when you go outdoors and come indoors, you can choose photochromic. If you have both of the usage, you can choose both lenses to meet your demands.
Source:http://www.allaboutvision.com/lenses/anti-reflective.htm
http://www.allaboutvision.com/lenses/photochromic.htm
