From the Department of Ophthalmology and Visual Science, Yale University:
DeBroff BM, Pahk PJ. The ability of periorbitally applied antiglare products to improve contrast sensitivity in conditions of sunlight exposure. Arch Ophthalmol. 2003;121:997-1001
To determine whether glare-reducing products such as eye black grease and anti-glare stickers reduce glare and improve contrast sensitivity during sunlight exposure, these intrepid eye doctors found 46 subjects (52% were women) and used a Pelli-Robson contrast chart (see above right) to assess the benefits of eye-grease, anti-glare stickers, and petroleum jelly applied to the infraorbital rim. Each subject was their own control and was randomized to one of the three eye treatments.....
Eye-grease wins. Better than stickers, better than petroleum jelly
but, probably not better than this for some of you......(work warning)