The Responsive Eye, MOMA, 1965, William Seitz, curator.

Perceptual abstraction – “ideological focus has moved from the outside world… and entered the incompletely explored region between the cornea and the brain.” As summarized by Princenthal in the Agnes Martin bio, “it’s dematerialized by uniform surface treatment, reflective or transparent materials, and a battery of optical devices; it’s primary purpose is to challenge perception.”
Seitz again, “It is easy to associate these large paintings with religious and mystical states. The contemplation of nothingness, which they invite while retaining their identity, quickly goes beyond purely visual sensation.” Such paintings gain admission to his exhibition, Seitz says, “because of the particular quality of visual attention they require, demanding that the eyes accommodate to them “as they do to a dimly lit room.”