The clinical study of ophthalmoscopic corneal images / by Ernest E. Maddox.

  • Maddox, Ernest E. (Ernest Edmund), 1860-1933.
Date:
[1892]
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Licence: Public Domain Mark

Credit: The clinical study of ophthalmoscopic corneal images / by Ernest E. Maddox. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    squinting eye, the obseiver viewing tlie imjige from just behind the candle. Later still, liirschberg showed how, by holding a ligiited taper before the patient's face in a case of strabismus, the degree of squint could be guessed by remarking the part of the cornea occupied by the image of the flame. His method does not seem to have come into use, perhaps for want of sufficient elaboration in detail, and too much neglect of the angle y. His method, however, is certainly of value, by enabling us to guess the amount of squint present. Ophthalmoscopic reflections from the cornea do not appear to have been utilized at all, till comparatively recently Priestley Smith showed how the image on a squinting eye can be used to measure the squint by his excellerj^ tape method', to which I am indebted for interesting me in^'a)rneal images. 1 leave, however, to be treated elsewhere the subject of the measurement of squint, con- fining myself now to its ophthalmoscopic detection and analysis, as being of value in general practice. Does one eye always squint, or either indifferently, is a question to be always put to one's self. In other words, is the squint alter- nating or monolateral ? In those of high degree it is most easy to settle this without the aid of corneal reflections, by simply covering the fixing eye for a few moments, so as to make the other one take up fixation instead. If the latter continues to fix after the removal of the hand, the squint is seen to be transferred to the eye which at first was straight, and the case is one of alternating strabismus. With minute squints it is not so easy to make out this point, and corneal images give immense assistance by letting us see at once which is the fixing eye: it is of course that eye in which the image occupies the fixation position: we can easily observe then, whether by covering this eye the other can or cannot be made to take up fixation. Another still more important point to settle is that of concomitancy, because by this alone can we tell whether or not a squint is paralytic. By concomitant squint Ave mean one in which the degree of squint remains the same when the patient looks in different directions. In paralytic cases, on the contrary, the squint increases on looking in the direction of action of the parah'sed muscle. Thus, in paralysis of the right external rectus, the squint increases on looking to the right, and so on. To test for concomitancy, I can strongly recommend the following simple method. Holding the ophthalmoscope in the usual way vfith the right hand, lay the palm of the left hand on the patient's head, with instructions to let the head follow the most gentle guidance of the hand without any resistance in the neck. Now bid the patient look at the central aperture of the mirror while the light is thrown on the squinting eye, and the exact position of the corneal reflex noted. Now slowly turn the head to the right and left, then up and down, etc., and notice if the position of the reflection is unchanged by these manoeuvres: if it is unchanged, the squint