Mark 8:25

‘Then again he laid his hands on his eyes, and he looked steadfastly (aorist - indicating the moment of truth) and was restored and saw all things clearly (imperfect - indicating the continuing result).'

After further action (a unique occurrence for Jesus' healings in the Gospels) full sight is restored, the half blindness slips away and he can see fully. In the light of the whole context as described above we may see this, not only as an actual miracle, but also as an acted out parable (like the cursing of the fig tree). It was Jesus' expectation that it would be thus with the disciples spiritually, first partly seeing and then receiving whole vision. And also with others who would follow them. Perhaps the partial healing reflects their somewhat defective recognition of Him as the Messiah, while the whole healing pictures what happens at the Transfiguration, or at His resurrection. But the idea is probably more in order to press home the fact that spiritual illumination comes slowly in stages. We should note here that in Scripture the healing of the blind is regularly seen to be God's prerogative (Psalms 146:8; Isaiah 29:18; Isaiah 35:5).