Why is anti-reflective coating so VERY important?  
 

An anti-reflective or anti-reflection (AR) coating is a type of optical coating applied to the surface of lenses and other optical elements to reduce reflection. In typical imaging systems, this improves the efficiency since less light is lost due to reflection. In complex systems such as telescopes and microscopes, the reduction in reflections also improves the contrast of the image by the elimination of stray light. This is especially important in planetary astronomy. In other applications, the primary benefit is the elimination of the reflection itself, such as a coating on eyeglass lenses that make the eyes of the wearer more visible to others, or a coating to reduce the glint from a covert viewer's binoculars telescopic sight. Wikipedia

 

 

1.  Nearsightedness (myopia) -  Light comes to focus in front of the retina rather than on the retina
2. Farsightedness (hyperopia) 
3. Astigmatism - Blurry vision resulting from  the eye not focusing light evenly onto the retina, the light-sensitive tissue at the back of the eye (see more below)
4. Prysobia - age-related, where close vision becomes harder to focus because of the decreased ability of the eye to change shape.

 

For example, regular plastic lenses reflect roughly 8 percent of light hitting the lenses, so only 92 percent of available light enters the eye for vision. High index plastic lenses can reflect up to 50 percent more light than regular plastic lenses (approximately 12 percent of available light), so even less light is available to the eye for vision. This can be particularly troublesome in low-light conditions, such as when driving at night. AllaboutVision
 

Astigmatism is all about the shape of the eye – the light doesn’t hit where it’s supposed to. The angle that is given on the prescription - allows for the right amount of light to enter the back of your eye/eyes.