Lens coatings help enhance the performance of your specs. There are many different lens coatings but the most common ones are anti-reflection, anti-scratch and ultraviolet protection (UV protection).
This can also be known as anti-glare coating. This coating works by reducing the amount of light reflection. For example, a camera flash may have the light reflected from your lenses if you don't have an anti-reflection coating. Another example is driving at night can be quite hazardous with all the street lights and oncoming car lights. Anti-reflection coatings removes the glare to make driving at night less dangerous, less stressful and smoother.
This can also be known as hard coating. No one wants to walk around with scratched lenses for appearance reasons but more importantly for vision reasons. Scratched lenses can hinder your vision or distract you from focusing. It's an annoyance that can be avoided. Plastic lenses and glass lenses are both prone to scratches, but with an anti-scratch coating, you will be giving your spectacles the protection and durability it needs.
UV protection coating
Ultraviolet light (UV) can damage your eyes. UV rays will not make you blind, but any lasting damages and consequences can lead to blinding. Over-exposure to ultraviolet light is thought to be a cause of cataracts, retinal damage and other eye problems. Just as UV can cause skin cancer, it can also cause eye cancer. This is why an ultraviolet protection coating is essential for protecting the body and general health.