Eyestrain (commonly called asthenopia) / by Ernest Clarke.

  • Clarke, Ernest, 1857-1932.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: Eyestrain (commonly called asthenopia) / by Ernest Clarke. Source: Wellcome Collection.

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    present be positively set down to the effect of over-use are the temporary, though prolonged, exhaustion (torpor retinae) which occurs in endemic night-bUndness—and forms also a part of what is called snow, ice and electric light blindness, and which after all is not accompanied by any visible ophthalmoscopical changes—and the in- flammatory changes which have in a few cases occurred on exposure to the intense light and heat of direct sun's rays,i but suggests that some few cases may occur where excessive use of the eyes may have induced disease of the fundus, and he gives notes of eight cases of choroiditis and choroido-retinitis in which eyestrain appears to have been the cause of the disease. Brailey gives lengthy notes of a case of choroido-retinitis in the yellow spot region, in a gentleman, aged 41, which appears to have followed work- ing at a fine pen-and-ink drawing.^ It is certain, however, that these objective signs are rare, and more often the symptoms are purely subjective. Night-blindness.—All healthy persons on first entering a dark room experience an inability to see, the epctent of which varies with the intensity of the light they leave and the darkness of the room ; in a short time physiological adaptation takes place, and objects become more and more discernible—they were temporarily night-blind. This condition exaggerated, occurs as a symptom of retinal exhaustion due to prolonged exposure to a great glare, such as is produced by the sun shining on a large expanse of snow, chalk, sea or sand, and is specially liable to attack those who are exhausted by fatigue, or disease such as scurvy. This idiopathic night-blindness is unaccom- ' Oph. Rev., vol. vii., p. 33. ^ Trans. Oph. Soc, vol. vii., p. 177.