The accident occurred on 13th October 1949 and he returned to his work on 7th November 1949. But before he did so, according to the evidence of his wife and himself, a marked impairment of his vision had been noticed and it grew worse. It was noticed a fortnight after the accident and on 3rd November 1949 he went to an optician. The optician told the plaintiff to see an opthalmologist, which, however, the plaintiff delayed doing. He continued in his employment until the end of March 1950. Then on 28th March 1950 for the first time he consulted an opthalmologist. An investigation ensued the conclusions from which in effect formed the foundations of the plaintiff's case. In the first place his acuity of vision was found to be so small that he could not see any of the letters on the card or screen; it was sufficient only for him to see a hand in front of his face and to count the fingers. For this conclusion reliance was necessarily placed upon his statements as to what he could see. In the second place as a result of an investigation of the eye itself and of other physical conditions and possible conditions and of the history of the case, it was considered that his loss of vision was to be accounted for by an atrophy of the optic nerve following retinal ischaemia. In the third place the optic atrophy was put down to the haemorrhage or exsanguination caused by the wound together with the shock and perhaps concussion occasioned by the accident, taking effect, it was thought, upon a man whose prior state of health was poor and who had habitually smoked to excess. This view of the cause of the optic atrophy was based on medical theory applied to the history of the case. It was supported by medical witnesses called for the plaintiff; but on the defendant's side opthalmologists were called who expressed a contrary opinion, an opinion that it was not due to ischaemia and that in any event there was no evidence of sufficient loss of blood to give rise to an ischaemia.