312 



Report of the Committee on Colour-Vision. 



" The fuDction is lowered throughout the whole of the field of 

 vision. The fields for white and the several colours are contracted 

 or abolished. As regards area, the least active region, viz., the 

 periphery, fails first ; the most active, the centre, fails last. As 

 regards colour-perception, the feeblest, viz., that for green, is 

 said to fail first ; the strongest, that for blue, last. I have not 

 tested the precise order in which the different colours are lost, 

 but I have ascertained in some cases that blue and yellow are 

 still recognised when red and green are no longer recognised. 



"These cases are characterised by undue proneness to fatigue 

 of the visual function. The field contracts while the eye is under 

 examination. The test is made with the registering perimeter. 

 The limit of the field is determined in each meridian in succession, 

 and on going round the field a second time, we find a further 

 contraction in each meridian, and obtain a spiral line as seen in 

 the chart exhibited. A blue glass placed before the eyes often 

 enlarges the field and raises the acuteness of vision, presumably 

 by cutting off the more exhausting rays. {See 4 Ophthalmic 

 Keview,' May, 1884.)" 



The practical outcome of the foregoing appears to be that a 

 man who has once been found to have normal form- sense and 

 normal colour-sense, need not be re-tested for colour so long as 

 his form-sense remains normal ; that is to say, if at any future 

 time he can still read the normal line of Snellen's types, he is 

 certainly not suffering from any acquired defect of colour-sense 

 at the centre of the retina. 



Eye Department. — Queen's Hospital. 

 Statistics of Tobacco Amblyopia. 



Year. 



Out Patients. 



Tobacco 

 Amblyopia. 



Percentage. 



1879 



293 



4 



1-70 



1880 



357 



4 



1*12 



1881 



439 



5 



1*14 



1882 



574 



2 



•35 



1883 



670 



6 



•89 



1884 



1,037 



13 



1-25 



1885 



1,581 



14 



•88 



1886 



1,722 



29 



1-68 



1887 



1,770 



17 



•96 



1888 



2,004 



29 



1-44 



1889 



2,197 



29 



1-36 





12,644 



152 



= l'207o 



Last 1,500 Private Patients. 



1,520 j 13 = -85 / o 



