The sudden development of bilateral occipital dysfunction is likely to produce transient physical and psychical effects in which mental confusion may be prominent. It may be some days before the relatives, or the nursing staff, stumble onto the fact that the patient has actually become sightless. This is not only because the patient ordinarily does not volunteer the information that they have become blind, but he furthermore misleads his entourage by behaving and talking as though they were sighted. Attention is aroused however when the patient is found to collide with pieces of furniture, to fall over objects, and to experience difficulty in finding his way around. They may try to walk through a wall or through a closed door on his way from one room to another. Suspicion is still further alerted when they begin to describe people and objects around them which, as a matter of fact, are not there at all.
Thus we have the twin symptoms of anosognosia (or lack of awareness of defect) and confabulation, the latter affecting both speech and behaviour.〔Macdonald Critchley, "Modes of reaction to central blindness", in Critchley, 1979, p. 156〕