Meryl Arbing , Jun 07, 2006; 06:58 p.m.
From what I have found the first T ('Transparent') coating was developed in 1935. It allowed light transmission of 80% compared to uncoated lenses. This led to further development for the military during the war (the NR coating). The T* coating (which was an improved T coating and transmitted 90% of the light passing through it) appeared in 1990.