When a glare beam enters the eye as a tiny pencil of light, we perceive the corneal scatter subjectively as a faint luminous veil, which is bordered by the screening effect of the iris.
Measurements of the luminance decrease at this shadow border indicated that the corneal share in entoptic scatter makes up some 30% between 30° and 70° angle of glare.
J. J. VOS and J. BOOGAARD, "Contribution of the Cornea to Entoptic Scatter," J. Opt. Soc. Am. 53, 869-873 (1963)