The Errors of Accommodation and Refraction of the Eye and Their Treatment: A Handbook for Students |
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accom accommodation power ametropia ametropic amplitude of accommodation anisometropia asthenopia astig atropine axis vert become binocular vision candidate cause ciliary muscle concave glass convergence convergence insufficiency convex glass convex lens cornea correcting glass curvature cycloplegic cylinder defect diffusion circles dioptres diplopia disc distant vision emmetropia emmetropic examination eyestrain fatigue five dioptres focal distance focussed front fundus headache high myopia homatropine horizontal hyperopia hyperopic eye insufficiency internal recti latent divergence lenses look Maddox metre angle modation muscular asthenopia myope myopia nearer normal eye oblique observed eye observer's ophthalmometer shows ophthalmoscope optic axis optical centre parallel rays patient point 33 cms point of reversal position posterior presbyopia presbyopic principal focus prism produce punctum remotum pupil rays passing rectus refraction represents retina retinoscopy right angles right eye seen shadow side spherical strabismus strain surface symptoms tion trial frame vergence visual axes
Popular passages
Page 176 - Snellen'a test types will be used for determining the acuteness of vision.) Squint, inability to distinguish the principal colours, or any morbid condition, subject to the risk of aggravation or recurrence in either eye, will cause the rejection of a candidate. . — The following additional points will then be observed : — (a.) That his hearing is good.
Page 176 - FIT. 2. If a candidate can only read D = 24 at 6 metres (20 English feet) with each eye without glasses, his visual deficiency being due to faulty refraction which can be corrected by glasses which enable him to read D = 6 at 6 metres (20 English feet) with one eye, and D = 12 at the same distance with the other eye, and can also read D = o'8 with each eye without glasses, at any distance selected by himself, he will be considered FIT.
Page 16 - The immediate antecedent of an attack is a condition of unstable equilibrium and gradually accumulating tension in the parts of the nervous system more immediately concerned, while the paroxysm itself may be likened to a storm, by which this condition is dispersed and equilibrium for the time restored.
Page 178 - In such a case the better eye must be emmetropic. Defects of vision arising from pathological or other changes in the deeper structures of either eye, which are not referred to in the above rules, may exclude a candidate for admission into the service. 6.
Page 78 - ... with that concave glass whose focal length is equal to the distance of the far point from the eye, and the converse is true; the measurement of myopia is that concave glass with which the myopic eye sees distinctly objects at a distance, and its focal length is equal to the distance of the myope's far point from the eye.
Page 81 - Schoolmasters should teach more, that is, they should explain and impart knowledge by demonstrations and simple lectures, and reduce as much as possible the time spent in " home preparation," which is usually work done by bad light and when the student is physically and mentally tired. Even in the nursery the greatest care should be taken. The little ones should...
Page 178 - ... with + 4 D or any lower power. 4. Hypermetropic astigmatism does not disqualify a candidate for the service, provided the lens or combined lenses required to cover the error of refraction do not exceed 4 D, and that the sight of one eye equals g- and of the other J, with or without such lens or lenses.
Page 178 - D = 12 at the same distance with the other eye, and can also read D = o'8 with each eye without glasses, at any distance selected by himself, he will be considered FIT. 3. If a candidate cannot read D = 24 at 6 metres (20 English feet) with each eye without glasses, notwithstanding he can read D = o'6, he will be considered UNFIT.
Page 178 - ... eye, will cause the rejection of a candidate. NB — In all other respects, candidates for these two branches of the service must come up to the standard of physical requirements laid down for candidates for commissions in the army. The Indian Pilot Service, and Candidates as Guards, Enginedrivers, Signalmen, and Pointsmen on Railways.
Page 67 - These skiascopes are designed to be held by the patient before the eye during rctinoseopic examination. Each contains a series of six lenses, ranging from 1 to 6 dioptrics, plus and minus respectively. In addition to these lenses there is on one side a movable slide containing a 6 D. lens, which can be quickly slipped up over the other lenses one after the other, making further combinations from 7 D. to 12 D. To determine smaller errors within 1 D. a slide containing three lenses. 0.25, 0.50, and...