On the third day after the operation he was asked what he saw. He answered that he saw an enormous field of light and misty objects moving upon it. These objects he did not discern. Only after four days did he begin to discern them, and after an interval of two weeks, when his eyes were accustomed to the light, he started to use his sight practically, for the discernment of objects. He was shown all the colours of the spectrum and he learned to distinguish them very soon, except yellow and green, which he confused for a long time. The cube, sphere and pyramid, when placed before him seemed to him like the square, the flat disc, and the triangle. When the flat disc was put alongside the sphere he distinguished no difference between them. When asked what impression both kinds of figures produced on him just at first, he said that he noticed at once the difference between the cube and the sphere, and understood that they were not drawings, but was unable to deduce from them their relation to the square and to the circle, until he felt his fingertips the desire to touch these objects. When he was allowed to take the cube, sphere and pyramid in his hands he at once identified these solids by the sense of touch, and wondered very much that he was unable to recognize them by sight. He lacked the perception of space, perspective. All objects seemed flat to him: though he knew that the nose protrudes, and that the eyes are located in cavities, the human face seems flat to him. He was delighted with his recovered vision, but in the beginning it fatigued him to exercise it: the impressions oppressed and exhausted him. For this reason, though possessing perfect sight, he sometimes turned to the sense of touch as to repose.
Abstract from Slepetz (The Blind) magazine 1912 (taken from Tertium Organum by P. D. Ouspensky)