This paragraph made me pay attention
When the distance vision is relatively preserved, certain subjects think that they can omit wearing glasses, except if they are forced to do so by necessity (reading on-board documents or instruments for pilots). This choice, made here by the pilot, necessarily implies accepting the significant deterioration of the near vision and intermediate vision. The result of this is that, unlike a subject who does not need such a correction, it is more difficult to detect and identify an apparently moving object which may "enter" the field of vision. Thus the monitoring of the flight parameters and outside obstacles during the takeoff may have been slowed down by the adaptation time caused by the alternation between intermediate and distant vision.