The determination of the necessity for wearing glasses / by D.B. St. John Roosa.

  • Roosa D. B. St. John (Daniel Bennett St. John), 1838-1908.
Date:
1887
Catalogue details

Licence: Public Domain Mark

Credit: The determination of the necessity for wearing glasses / by D.B. St. John Roosa. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    and so forth, by the ophthalmoscope. The general practitioner who has not learned to use this instru- ment will be obliged to stop at this point in these cases. But he can at least tell his patient, that he is not merely presbyopic but also amblyopic, and that no glasses will enable him to see clearly. Paresis of the accommodation, as is well known, sometimes occurs as a result of diphtheria, acquired syphilis, injuries, and so forth. In this case convex glasses are often of service while recovery is taking place, or even if the paresis be permanent. A presbyopic patient will require stronger glasses as time goes on. But no fear need be felt, if no or- ganic disease exist in the eye, but that a glass may al- ways be found to correct the error of accommodation. The same rules apply for changing glasses as for first putting them on. At first, presbyopes will only require glasses in the evening and for small type, or for work upon fine objects, but soon they will be re- quired by day. Then the glasses first chosen may be used by day, and a stronger pair at night. The accommodative power is hardly established before it begins to decline in vigor. The near point of distinct vision for fine objects begins to recede in early youth, and when three score and ten are reached it becomes one with the far point, there is no accom- modative power, no range of accommodation. This can not be entirely referred to want of contractile power of the ciliary muscle, unless the muscle is unlike