The optical manual, or Handbook of instructions for the guidance of surgeons in testing the range and quality of vision of recruits and others seeking employment in the military services of Great Britain, and in distinguishing and dealing with optical defects among the officers and men already engaged in them / by T. Longmore.

  • Longmore, T. (Thomas), Sir, 1816-1895.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: The optical manual, or Handbook of instructions for the guidance of surgeons in testing the range and quality of vision of recruits and others seeking employment in the military services of Great Britain, and in distinguishing and dealing with optical defects among the officers and men already engaged in them / by T. Longmore. Source: Wellcome Collection.

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    CHAPTER III. OBJECTIVE ASSESSMENT OF OCULAR REFRACTION. PAGE Subjective aud objective modes of visual examination . . .104 Objective assessment of refraction 105 Two methods commonly employed 105 1. Direct Method of Ophthalmoscopic Diagnosis. Conditions which concern the eye observed . . . . .106 Direction of rays emitted by an Emc. eye 100 By a Me. eye . . . .106 By a He. eye .... 107 Conditions which concern the ob- server 107 Effect of rays from Emc. eye on observer . . . . .107 Of rays from Me. eye . . .108 Of rays from He. eye . . . 109 Application of observations to dia- gnosis 109 Erect and inverted images . . 109 Objective diagnosis of Em. . .110 Of M 110 Of H 110 OfAst Ill Measure of ametropia by7 refraction ophthalmoscopes . . .111 Description of refraction ophthal- moscopes . . . .Ill Manner of employing them . . 112 Observation of Emc. eye . . 114 Diagnosis of degree of M. .114 Of degree of 11. . . . .114 Remarks on the use of refraction ophthalmoscopes . . .115 2. Keratoscopy. Keratoscopy in military practice . 116 Arrangements necessary . . 116 Appearances in keratoscopy . .117 Nature of keratoscopy . . . 118 Keratoscopy with concave mirror 118 Estimating ametropia by it . . 119 Application in practice . .120 Diagnosis of degree of M. or II. . 120 General estimate of M. by kerato- scopy 120 Measure and correction of Ast. by it 121 Keratoscopy with plane mirror . 121 CHAPTER IV. ACCOMMODATORY FUNCTION OF THE EYE. Accommodation. Act of Acc...... 123 Demand for Acc..... 123 Mechanism of Acc. 124 Power of Acc. .... 126 Expression of amount of Acc. 126 Measure of amount of Acc. . 126 Region of Acc. .... Association of Acc. and converg- 128 ence 129 Presbyopia. Definition ..... 130 Optical conditions . 131 Causes .... . 131 Diminution of Acc. with age . 132 Symptoms .... . 133 Diagnosis . . . . 133 Determination of degree of Pr. . 134 Examples .... . 134 Correction of Pr.. . 134 Range of A cc. in Pr. vision . . 134 Pr. with M. . 135 Pr. with H. ... . 135 CHAPTER V. ON IMPAIRED VISION CONNECTED WITH STRABISMUS. Strabismus. Definition . Various forms of strabismus Directions of deviation in strabis- 137 mus. . . . , .137 137 Apparent strabismus . . .138