Sight isn't necessary to play chess. Many sighted players strive to become proficient at playing without using their eyes. Visually handicapped players don't have an option and, in fact, for the most part have been saddled with using equipment originally intended for sighted players, modified to make them usable for those who can't see.
Usable doesn't mean optimal or even good. Over the years some attempts to design equipment from a blind player's point of view have been made with some interesting results, but nothing that seems to have caught on. The reader can see some of the current and experimental equipment in an earlier article called Blind Ambition.
There are several reasons I can imagine why the blind might still be using the same equipment designed a century ago :
-The equipment currently in use is the best design so far.
-New designs have proven to be to expensive or impractical
to maunfacture for the size of the potential market.
-The players are very indisposed to change.
For the most part designers tend to look for innovations that will appeal to the masses. The number of visually handicapped chess players is rather tiny and improving their lot isn't something most people even think about.
One product designer, Peter Schwarz, who goes by the handle ExileGerman, is trying to develop an innovative type of board/set for the blind by rethinking the problem and incorporating an imaginative solution.
The image above represents the pieces.
Clicking on the picture will take you to Mr. Schwarz's Chessboard-for-the-Blind blog
What I would like is for readers to at least visit his blog and those with ideas or thoughts to share them with him both for encouragement and as enrichment. Designing must be a difficult task, but without enough suitable feedback it must also be frustrating and even more challenging. Mr. Schwarz's goal on this ill-trodden path is a worthy and needed one . . . a potential footprint in chess history.