That can intromit or let in (light); relating to intromission.
The Century Dictionary (Public Domain)
Use "intromissive" in a sentence
"Suhrawardi begins with a criticism and a rejection of the prevalent ˜extramissive™ and ˜intromissive™ theories of vision on account of the materialist implications of the imprinting of forms in the material substratum of the eye."