New truths in ophthalmology / as developed by G. C. Savage.

  • Savage, G. C. (Giles Christopher), 1854-1930.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: New truths in ophthalmology / as developed by G. C. Savage. 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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    arc of distortion that would throw strain on the superior ob- liques is 1300 (from a to d). -if in this pair of eyes the me- ridians of greatest curvature had been at 1300 for the right and 50° degrees for the left, the arc of distortion that would call the inferior obliques into action would be only io°, while the one that would cause activity of the superior obliques would be 1700 (1800 less io°). Fig. 1, Plate V., represents hypermetropic astigmatic eyes, the meridians of greatest curvature being at 1800 {a) in each eye, a condition that, in itself, would not call either the superior or inferior obliques into activity. The correct plus cylinders, axes 1800, would sharpen the blurred but not distorted images. Displacing these axes in the lower temporal quadrants would so distort the images as to throw into action the superior obliques; and the maximum of dis- tortion would be effected when the axes reached 450 (c) in the right and 1350 (c) in the left eye. With the axes turned to 900 (d) there would be no distortion of images, though there would be blurring, as in all cases of displaced cyl- inders. Fig. 2, Plate V., represents the same pair of eyes shown in Fig. 1. The axes of the correcting cylinders revolved in the lower nasal quadrant would so distort images as to call into action the inferior oblique muscles, the maximum being effected when the axes stand at 135° (c) for the right and 45° (c) for the left eye, the distortion lessening as the axes