This post is now a couple of months old, but I just ran across it and gotta weigh in to straighten this out...
There is no exclusive source for optical glass available to Leica and Swarovski or anybody else. Swarovski, Zeiss, and Leica all purchase lens blanks primarily from two sources: Schott & Hoya. Until recently Schott and Zeiss were sister companies in that they were both owned by the same parent organization in Germany, but that is really neither here nor there, as Schott is more than happy to sell glass to anybody who can pay their bills.
There is no such thing as HD-type coating. "HD" refers to a high quality type of glass that has been used for many years in all premium binoculars and has only recently been turned into a marketing "buzzword."
As most of us age our pupils will no longer dilate to the diameters they once did. This is the reason, for example, that many folks have difficulty driving at night when they get older. There is a logical argument, therefore, that older users can't benefit from larger aperture binoculars like 8x50s because their pupils can't dilate enough to take advantage of larger exit pupils. Beyond that there is no age issue. Many people retain very high visual acuity well into old age, and can therefore benefit from the effects of HD glass and any other premium optical enhancements.