Progress in optics during the past 300 years has not been continuous, but has occurred in a succession of forward leaps with periods of stagnation between. Often the industry has had to wait for a development in some entirely different field before progress could be resumed, although the precise form of its need was often not realised at the time. In particular, the development of telescopes, microscopes, and photography was often delayed by impasses of this kind.
Rudolf Kingslake, "Some impasses in applied optics," J. Opt. Soc. Am. 64, 123-123 (1974)