How to use the ophthalmoscope : being elementary instructions in ophthalmology ; arranged for the use of students / by Edgar A. Browne.

  • Browne, Edgar A.
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: How to use the ophthalmoscope : being elementary instructions in ophthalmology ; arranged for the use of students / by Edgar A. Browne. 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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    focus behind the eye (say 10 inches), and could be rendered parallel by a convex lens of 10 inches principal focal length. Hence, with a 10-inch eye-piece we can approach within 2 or 3 inches of the patient's eye, and see the details perfectly clearly. [With an emmetropic eye the convex lens would render the return rays convergent, and consequently details would be blurred.] The strongest glass (subtracting the distance between the eyes) with which we can see details clearly is approximately the one required to correct the hypermetropia. With the indirect examination the image is in- creased by approaching the objective to the patient's eye, and vice versa* * Over-sighted or hypermetropic persons are not so easily detected for practice as myopic. They may generally be known by com- plaining of uneasiness or pain after reading, sewing, &c, by slightly imperfect sight for distant objects, imperfect or difficult vision for minute objects held close to the eye, and by improvement result- ing from convex glasses. A young woman who likes to see in her mother's spectacles, and can see through them at a distance, is a safe subject.