Licence: Public Domain Mark
Credit: Eyestrain (commonly called asthenopia) / by Ernest Clarke. Source: Wellcome Collection.
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Licence: Public Domain Mark
Credit: Eyestrain (commonly called asthenopia) / by Ernest Clarke. Source: Wellcome Collection.
![CILIARY STRAIN (ACCOMMODATIVE ASTHENOPIA.) I. THE CAUSES OF CILIARY STRAIN.—Fatigue of the ciliary muscle occurs in :— Emmetropia Direct [ Abuse in the healthy. 111. Diminished accommodative power, due to {a) Age. {J}) Nervo-muscular debility [ Neuras- thenic Asthenopia]. {c) Congenital defect. \{d) Disease of the eye.] Reflex ( Reflex Asthenopia ). Ametropia ( Accommodative Asthenopia ) in :— 1. Hyperopia. 2. Astigmatism. 3. Presbyopia. 4. Anisometropia. II. CILIARY STRAIN IN EMMETROPIA (strain of the accommodation in those who have no error of refraction) :— In the perfectly healthy.—This is simple ordinary fatigue, and is Nature's outcry against the overuse or abuse of the ciUary muscle. Who has not, some time or another, after, say, an evening's close work, complained of the eyes, and often the head, aching? The night's rest removes these symptoms of eyestrain, as it does most other forms of fatigue. Two men similarly constituted in every re- spect may each read eight hours a day, and while one suffers from asthenopia towards the end of the day, the other may escape it by giving his ciliary muscle fre-](https://iiif.wellcomecollection.org/image/b20395747_0047.jp2/full/800%2C/0/default.jpg)
