This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ...conical cornea, nebulas, and ulcers. Little can be done in the way of glasses towards correcting this form of astigmatism, though much improvement of vision sometimes occurs when stenopaic spectacles are worn, the opening being made to suit the peculiarity of each case. We now pass on to the much more common variety, ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ...conical cornea, nebulas, and ulcers. Little can be done in the way of glasses towards correcting this form of astigmatism, though much improvement of vision sometimes occurs when stenopaic spectacles are worn, the opening being made to suit the peculiarity of each case. We now pass on to the much more common variety, which can frequently be exactly corrected by the help of piano-cylindrical lenses. Regular astigmatism is due to the curvature of the cornea being different in the two meridians, that of maximum and minimum refraction; these are called the chief meridians, and are always at right angles to each other. In the normal eye the cornea is the segment of an ellipsoid and not of a sphere, so that there is a slight difference in the refraction of the two chief meridians, the focus of the vertical meridian being slightly shorter than that of the horizontal. This can easily be proved by looking at a card on which is drawn two lines crossing each other at right angles; the card is held close to the eye and gradually made to recede; both lines cannot be seen at the same time with equal clearness, the horizontal being seen clearly at a shorter distance than the vertical line. So long, however, as the acuteness of vision is not impaired it goes by the name of normal astigmatism, or regular astigmatism of the normal eye. Parallel rays passing through a convex spherical glass come to a focus at a point. If the cone of light thus formed be divided perpendicular to its axis, at any point between the lens and its focus, or beyond the focus after the rays have crossed and are diverging, a circle is formed. In astigmatism the case is different: if parallel rays pass through a convex lens which is more curved in the vertical than in the horizontal meridian, those ray...
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Add this copy of The Refraction of the Eye: A Manual for Students to cart. $19.72, new condition, Sold by Ingram Customer Returns Center rated 5.0 out of 5 stars, ships from NV, USA, published 2022 by Legare Street Press.
Add this copy of The Refraction of the Eye, a Manual for Students to cart. $22.50, fair condition, Sold by Quirky Used Books rated 4.0 out of 5 stars, ships from Albuquerque, NM, UNITED STATES, published 1894 by P. Blakiston's Son & Co.
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Seller's Description:
Fair. Hardcover. Blue cloth-bound boards. Significant wearing to cloth on the spine ends. Scraping to outside edges of boards. Foxing on board cloth and pages. Writing on FEP and paste down (former owner and clinic name). Bent corner tips. Splits to the Smyth sewing binding in between page signatures. Eye testing chart still affixed in the back of the book. Photos furnished upon request and suggest that you do so. 254 pages.
Add this copy of The Refraction of the Eye: a Manual for Students to cart. $23.39, fair condition, Sold by Anybook rated 4.0 out of 5 stars, ships from Lincoln, UNITED KINGDOM, published 1900 by J. & A. Churchill.
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Seller's Description:
This is an ex-library book and may have the usual library/used-book markings inside. This book has hardback covers. In fair condition, suitable as a study copy. No dust jacket. Re-bound by library. Please note the Image in this listing is a stock photo and may not match the covers of the actual item, 650grams, ISBN:
Add this copy of The Refraction of the Eye a Manual for Students to cart. $25.00, very good condition, Sold by Nick Bikoff's Books, IOBA rated 1.0 out of 5 stars, ships from Fairfield, NJ, UNITED STATES, published 1895 by Chas. J. Oliver.
Add this copy of The Refraction of the Eye: A Manual for Students to cart. $29.16, new condition, Sold by Ingram Customer Returns Center rated 5.0 out of 5 stars, ships from NV, USA, published 2022 by Legare Street Press.
Add this copy of The Refraction of the Eye: A Manual for Students to cart. $31.38, new condition, Sold by Ria Christie Books rated 4.0 out of 5 stars, ships from Uxbridge, MIDDLESEX, UNITED KINGDOM, published 2022 by Legare Street Press.
Add this copy of The Refraction of the Eye: a Manual for Students to cart. $37.46, fair condition, Sold by Ladylisabooks rated 5.0 out of 5 stars, ships from Chester, , UNITED KINGDOM, published 1900 by J. & A. Churchill.
