332 Report of the Committee on Colour-Vision, 



Question — You think it would be advisable after a railway 

 accident to test the driver and guard for central amblyopia ? — 

 Yes ; I think it would be well to do so some little time after 

 the accident, since shock is one of the causes of the lowered 

 vigour which so often precedes this failure of sight. I had the 

 following case in point: — A railway servant jumped off the 

 foot-board of a train moving at about 10 miles an hour. He 

 was badly shaken, and his general symptoms were for a time 

 suspected to indicate grave degeneration of the brain and spinal 

 cord. His sight also failed, and this was also thought to point 

 in the same direction, until it was found, on careful examination, 

 that he had the scotoma of tobacco amblyopia, and that he 

 smoked. His sight returned perfectly when he left off smoking ; 

 he also gradually recovered from the symptoms of shock. 



Question — Your opinion is that, contrary to the ordinary 

 so-called colour-blind persons, these people with central scotoma 

 have a sufficient defect of form-sense to warn them? — It is 

 always great enough to be a safeguard. It is the same with 

 other diseases of the optic nerve, but the clinical features 

 of cases of atrophy of the optic nerve, from whatever cause, 

 are, generally speaking, less uniform than those of the axial 

 neuritis that occurs commonly from tobacco smoking, and 

 perhaps occasionally from other toxic influences, and as a 

 substantive disease. The axial neuritis group presents tolerably 

 uniform symptoms, because only certain bundles of fibres of the 

 optic nerve are diseased, viz., those which supply the central area 

 of the retina, the disease very seldom spreading to the other 

 bundles. The symptoms in other forms of optic nerve disease are 

 less constant, because the malady does not show any such constant 

 selective affinity for certain strands of fibres, but may affect some 

 or all, and with various degrees of severity and of permanence, 

 according to the seat and nature of the originating cause. In 

 one very important group of cases, the group known generally 

 as " progressive atrophy " of the optic nerve, it is the rule to find 

 that the field of vision in the earlier stages is curtailed at its 

 circumference, either all round (" concentric contraction)," or 

 more commonly by the loss of sector-shaped pieces. Together 

 with such total loss of portions of the field there is usually a 

 lowering of sensibility over the area that remains, so that " acute- 

 ness of vision" is damaged also; but sometimes the centre 

 remains very good in spite of great loss of peripheral vision. 

 This " progressive atrophy" is most commonly a part of a similar 

 disease affecting the spinal cord (and sometimes the brain) 

 in the form of tabes dorsalis or locomotor ataxy. Marked 

 colour-blindness is the rule in progressive optic atrophy, but, 

 according to my own rather rough clinical notes, the loss 

 of colour perception does not stand in a perfectly uniform 

 relation with loss of (central) acuteness or with loss of field ;* 



* I have not collected any observations on this point since publishing 

 such as I then had, in 1883, in vol. iii of the " Trans, of Ophth. Society," 

 p. 256. 



