Photochromic or transition lenses that darken outdoors are useful if you're sensitive to sunlight. They block 100 per cent of the sun's ultraviolet rays, so you don't need prescription sunglasses. Although you cannot repair scratches on lenses with other coatings, it's possible to repair scratches on transition lenses.
Hold the glasses under a faucet and wet them with lukewarm or warm water.
Wipe the glasses dry with a soft, lint-free cloth. This will remove dust or debris that may cause additional scratches while you are attempting to remove the existing scratch.
Use the white grease pencil to draw a circle around the scratch on your transition lens.
Take the chamois cloth and blend the grease pencil mark into the lens by rubbing gently in a circular motion. The light friction and heat of the rubbing will blend away the scratch or fill it. Continue buffing and polishing until the scratch disappears.
You can find a white grease pencil at any office supply or craft and hobby store.
This method will not work for deep scratches. Take your glasses to an eyeglass specialist.