THE DELETERIOUS EFFECTS OF BRIGHT 

 LIGHT UPON THE EYES 



Bv J. HERBERT PARSONS, B.S., D.Sc.(Lond.), F.R.C.S.(Eng.) 



Assistant Ophthalmic Surgeon, University College Hospital, London ; Assistant Surgeon, Royal 

 London ( Moorfields) Ophthalmic Hospital, etc. 



It is well known that bright light under various conditions is 

 detrimental to the sight. In recent times great progress has 

 been made in the development of the many methods of artificial 

 illumination. Gas light, although at one time threatened with 

 supersession by the electric light, has taken a new lease of life 

 owing to the introduction of incandescent mantles, whilst a secure 

 and unassailable position has been gained for the electric light 

 by its perpetual modification and improvement. Each subserves 

 a useful function in civilised life, each being adapted to require- 

 ments which are less efficiently satisfied by the other. It must 

 be admitted that there has been something haphazard in the 

 •development of these illuminants for the use of mankind. 

 Inventors and engineers have held only one chief problem 

 before their minds — the provision of maximum illumination at 

 minimum cost. They have until recently not troubled them- 

 selves at all about the physiological aspects of the question ; but 

 it has now become imperative that this view of the problem 

 shall receive due attention. It is the object of this paper to 

 review briefly the recorded cases of the manifold deleterious 

 effects of bright light upon the eyesight, to analyse them as 

 far as may be so as to discover the conditions which predicate 

 detriment to the eyes, to consider how far these conditions 

 prevail in the use of modern artificial methods of illumination 

 and to demonstrate the precautions which must be adopted to 

 avoid danger. 



Even a scanty acquaintance with the diseases of the eye 

 which follow exposure to intense light suffices to show the 

 multiplicity of its effects. Attention was first prominently 

 drawn to the subject by cases of partial or complete blindness 

 resulting from the observation of eclipses of the sun with the 



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