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pressure have been made, the man's vision will be rendered misty, and it will be necessary to wait a minute or two until the recovered its normal state before applying the test for visual power. The assistant should be taught to cover the eye by the palm of the hand, formed into a hollow for the purpose. If the fingers are employed, they are apt to press upon the globe, and there may inadvertently be vacant spaces left between them; in which case, either accidentally, or intentionally taking advantage of the opportunity, the eye not under examination may look through one or other of these openings.

If a trial case of lenses be available, it is still better to use the spectacle frame, and to place either a ground glass or opaque metal disc, both of which are usually supplied with such cases, in front of the eye not under trial. Not only is pressure on the globe thus prevented, and all chance of the person seeing through chinks obviated, but the freedom of movement of the eyelids is not interfered with.

7. Application of Test-dots.If the man under examination be a recruit, as soon as he is placed in position, the test-dots are held upright before him at the prescribed distance-10 feet in the case of a recruit for the regular army, and 5 feet for militia and departmental corps recruits-and he is asked to state the number of dots exposed to his view, in the manner already explained at page 189. He should be required to count two or three series of dots with each eye, and if he replies readily and satisfactorily, so far as power of vision is concerned, he is fit for service.1

8. Rejection of a Recruit.-If the recruit should make repeated mistakes in counting the number of dots presented to him at the prescribed distance, and there is no reason for suspecting that he is not doing his best to try to see them clearly, especially if he should succeed in counting them correctly when they are held at some point nearer to him than the prescribed distance, he is then rejected as unfit for service on account of defective vision.' The regulations do not require that the nature or degree of the defect should be particularly stated at the first inspection of recruits.

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9. Relative Visual Acuteness of the two Eyes. As recruits in aiming and firing practices are taught to use the right eye only, the left being closed, it seems worth consideration whether it is necessary to insist on men seeking enlistment having the same range and power of sight in the left as in the right eye, particularly under a system of engagement for short service. Compliance with

The following regulation on the application of test-dots is given in paragraph 986 of the latest published Army Medical Regulations of 1885. In examining a recruit's vision he will be placed with his back to the light, and made to count the dots and describe their position at the distances specified on the test-dot card. first with both eyes and then with each separately: the medical officer will manipulate the card, while the assistant covers each eye alternately with the flat of his hand.

the authorised standard of visual power does not exclude a man who has simple M. of about 1.5 D, or. And, supposing this to be the degree of M. of his right eye, although the M. were as high as 3 D,, in his left eye, there hardly seems to be any valid reason against accepting him as a recruit. Even if the visual acuteness of the left eye were lowered by the M. being complicated with Ast., so long as the visual defect is one of refraction only, not one of any morbid origin involving a liability to recurrence of the disorder, it would not prevent him from seeing pretty well for certain distances, and from doing ordinary duties in the ranks and in marching; and there hardly seems to be good ground, therefore, under the present system of using the rifle, for rejecting him as a recruit if he be eligible in all other respects.

The quality of vision of the left eye seems to be regarded as of minor importance in the case of recruits for the militia, for it is specified, with regard to the medical examination, that one of the principal points to be attended to is that the recruit's vision is good, or at least sufficiently good to enable him with his right eye to discern objects clearly at not less than 300 yards, while no quality of vision is referred to as regards the left eye.-(Regs. for the Militia, W.O. 1883, Part I. sec. 2, p. 32.)

10. Defective V. due to Nephelopia or opacity of some of the Anterior Dioptric Media. Diminished translucency of the central portions of the cornea consequent on keratitis, diffused deposit of lymph on the capsule of the crystalline lens after iritis, and, indeed, cloudiness of the anterior media of the eye from any cause, even though they may not exist to such an extent as to be readily obvious to external observation, cause indistinctness of vision from the diffusion of the rays of light by which the structures concerned happen to be traversed. If the loss of transparency is not considerable, the circular test-dots in present use may be counted at a distance of 10 feet in a good light, but it may be found that a recruit cannot count them beyond that distance. It is questionable, unless there is an urgent demand for recruits, whether a man should be regarded as fit for military service under such conditions, especially if the right eye is concerned, although he is able to count. the test-dots at the prescribed distance. It is not merely that a maximum limit of 10 feet in counting the test-dots represents rather less than one-fourth of Snellen's standard of visual acuteness, but in a large proportion of such cases a liability to recurrence of inflammatory action exists, and should this take place an aggravation of the existing defect is almost inevitable.

11. Procedure when Imposition is suspected. In the British service, as recruits are for the most part men voluntarily seeking enlistment as soldiers, not like the majority of conscripts in Continental armies trying to escape enlistment, if any efforts at all are made by them to practise imposition, they will probably be directed

to the concealment of any defects of V. they may labour under, rather than to their exaggeration.

If, however, there is cause for suspecting that the man who has volunteered for enlistment has changed his desire on the subject, and that he is trying to escape from the bargain he has so far entered into by assuming a visual defect which does not really exist, he must be subjected to further tests before he is pronounced unfit for service on this account.

12. Visual Examination at Secondary Inspection of Recruits.Many instances have occurred in which a recruit at first examination has been passed fit in respect to visual power and range, but, on being subjected to secondary inspection, has been found unable to count the test-dots accurately at the proper distance with one or other eye, or even with both eyes. At the secondary inspection, when the test-dots are placed before the man, he may perhaps give a succession of wrong replies as to the number of dots exposed to his view. Great caution should be exercised in such a case as to the rejection of a recruit. The presumption is certainly that he was properly tested at the first examination, and that for private reasons he does not choose to count the test-dots correctly at the secondary inspection. Unless there is some evident ocular defect which has been overlooked at the former inspection to substantiate the man's statement, a case of this kind is calculated to excite strong suspicion of the disability being feigned, and systematic steps should be taken to ascertain whether the man's statements are true or false. This can be done by ascertaining the man's alleged V. when the test-dots are placed before him, and then comparing it with the results obtained from the application of other test objects, Snellen's types, for example, as elsewhere explained.

The following special direction on the point just referred to is published in the Army Medical Regulations of 1885, para. 987:— A recruit whose vision has been tested and pronounced good on a primary examination will not, through his own declared inability to see the test-dots on secondary examination, be rejected unless the approving medical officer is satisfied that the man's vision is really defective and no deception is being practised by him.'

13. Field of Vision. It is important that a recruit should not only possess sufficient central acuteness of vision, but that he should also have his field of vision complete in both eyes. Loss of the outer or temporal portion of the field of view of either eye from any cause especially unfits a man for military duty, for it disables him from noticing the objects by which he may be surrounded on the defective side and, consequently, from properly steering his way among them. A considerable portion of the lateral field of view belongs solely to the eye on the side concerned, as elsewhere explained, and a deficiency in it is not in any degree supplied or

compensated for by the eye on the opposite side. The temporal portion is not a part of the field of view which is common to both eyes, and when this portion is absent, objects on the side concerned do not attract observation or attention so long as a soldier. is marching and looking directly forward. The manner in which the existence of deficiency in part of the field of vision is to be ascertained has been already described (see page 12).

14. Visual Examination of Trained Soldiers.-When it is necessary to determine the V. of a soldier already in the service, the general manner of conducting the examination is the same as with the recruit, only the test-types should be used instead of the test-dots. The trial by the test-dots at a prescribed distance, as before explained, has been specially ordered for men seeking admission into the army. In the cases of trained soldiers already serving, a complete examination is required, as more important issues depend on the decision at which the surgeon may arrive. The question usually submitted to the medical officer is whether the inefficiency of a soldier who shows himself to be a specially bad shot at particular distances at the annual course of musketry instruction, or who shows himself incapable of judging distance with an approach to correctness, is due to some visual defect or not. The nature of the defect, if defect exist, and the extent to which it disqualifies the man for duty, have therefore to be ascertained and stated with accuracy.

15. Use of Snellen's Test-types. -In such cases the degree of V. must first be determined, and this is very easily done by Snellen's test-types or test-figures. The mode of ascertaining and expressing the acuteness of vision by these objects has been explained at page 163.

16. Vision not defective. If the tests are so answered as to show that the man under examination possesses average normal V., or a near approach to the average, all morbid states of the eye, such as limitation of the field of vision, as well as disorders of its appendages, being understood to be excluded, the subjects of complaint are manifestly not due to visual defect.

17. Procedure if Vision be defective. If V. is proved to be considerably under the average, the cause of the deficiency must be ascertained.

In the first instance, particular and special attention must be paid to the examination of the anterior ocular structures. The cornea, anterior chamber, iris, and crystalline lens of the affected eye should be subjected to minute observation. In the case of a recruit at secondary inspection, defects may possibly be found to exist in these structures sufficient partially to obscure V. which were not perceived in the observation of the eyes made at the primary inspection, although this could hardly occur if the tests for eyesight had been properly applied. They may equally exist in the case of

a soldier serving in the ranks, without being visible by ordinary observation, as the result of some inflammatory action to which the eyes have been subjected. This preliminary inspection is important and should invariably be made. Considerable time is often wasted afterwards when it has been neglected.

18. Lateral Illumination.-The superficial examination is very rapidly made by lateral illumination, and indeed can only be thoroughly accomplished by its means. Lateral illumination signifies lighting up the parts required to be observed by concentrating upon them a pencil of rays cast in an oblique direction. The man is brought near the window of the room, one of the bi-convex object lenses in the optical case is placed vertically near the outer angle of the eye under observation in such a way that the light passing through it is made to converge upon the cornea, or through the

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cornea on the iris or lens, and the condition of all these structures is then examined by the spectator standing in front. This lateral illumination is of course more brilliantly seen when the flame in the ophthalmoscopic room is used as the source of light, but is sufficiently marked by solar light on any ordinarily clear day. By these means the slightest roughness of the surface of the cornea, interstitial haziness, minute ulcers, or the remains of them, fine exudations at the margin of the pupil, posterior synechiæ, commencing cataract, are made most obvious to observation, while the pencil of rays at or near its focus is made to play upon each structure at pleasure. Nothing can be more beautiful than the perfect precision with which opacities of the cornea and lens, adhesions of lymph to the capsule, and other morbid changes, some of which may not be perceptible under ordinary observation, become defined by light

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