A Manual of Ophthalmic Practice |
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Page 3
... lenses . Prism . - In optics a prism is any transparent medium comprised between two plane faces inclined to each ... Lenses . We next come to the consideration of lenses. B 2 PATH OF RAYS IN PRISMS . 3.
... lenses . Prism . - In optics a prism is any transparent medium comprised between two plane faces inclined to each ... Lenses . We next come to the consideration of lenses. B 2 PATH OF RAYS IN PRISMS . 3.
Page 4
... lenses . These are usually made of crown or flint glass , of which the latter A B C D E F FIG . 4 . is the more highly refractive ; spectacle lenses are fre- quently made of what is known among opticians as " pebble " or rock crystal ...
... lenses . These are usually made of crown or flint glass , of which the latter A B C D E F FIG . 4 . is the more highly refractive ; spectacle lenses are fre- quently made of what is known among opticians as " pebble " or rock crystal ...
Page 5
... lens only need be considered , and in the second the double concave , as the properties of each of these lenses apply to all those of the same group . The spherical lenses used in ophthalmic practice are almost always double convex , or ...
... lens only need be considered , and in the second the double concave , as the properties of each of these lenses apply to all those of the same group . The spherical lenses used in ophthalmic practice are almost always double convex , or ...
Page 6
... lens . D F E L N -M FIG . 5 . Conjugate foci . - We will now consider the case in which the luminous object is further from the lens than its principal focus , but so near that all incident rays of light form a divergent pencil , as ...
... lens . D F E L N -M FIG . 5 . Conjugate foci . - We will now consider the case in which the luminous object is further from the lens than its principal focus , but so near that all incident rays of light form a divergent pencil , as ...
Page 7
... lens , the ray cuts the axis at a point I which is more dis- tant than the principal focus F. As all rays from the ... lens , the divergence of the emergent rays increases and the focus n -K G M FIG . 7 . I becomes more distant ; when ...
... lens , the ray cuts the axis at a point I which is more dis- tant than the principal focus F. As all rays from the ... lens , the divergence of the emergent rays increases and the focus n -K G M FIG . 7 . I becomes more distant ; when ...
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Common terms and phrases
accommodation affected amblyopia anomaly of refraction anterior chamber appear asthenopia astigmatism atrophy atropine axis bandage become blood cataract cause centre chamber choroid ciliary region colour commenced concave lens congenital conjunctiva convergence convex lens cornea corneal margin corneitis curette curvature degree of myopia dilated dioptric direction disease displacement distance emmetropic examination extraction eyeball eyelids forceps foreign body fundus glasses glaucoma globe hæmorrhage horizontal hypermetropia hypermetropic astigmatism incision increased inflammation inflammatory injury intolerance of light iridectomy iris iritis keratitis knife lachrymal lenses less lids lines lint lotion muscle myopia object occur ocular opacity opaque operation ophthalmia ophthalmoscope optic disc orbit pain paralysis passed patient performed portion posterior presbyopia pupil rays of light removed retina retinal vessels right angles scissors sclerotic seen sight spots staphyloma strabismus suppuration surface sutures sympathetic ophthalmia symptoms synechia syphilitic tension tion treatment tumour ulceration usually vitreous wire speculum wound
Popular passages
Page 318 - Walsham, besides being an excellent surgeon, is a teacher in its best sense, and having had very great experience in the preparation of candidates for examination, and their subsequent professional career, may be relied upon to have carried out his work successfully. Without following out in detail his arrangement, which is excellent, we can at once say that his book is an embodiment of modern ideas neatly strung together, with an amount of careful organisation well suited to the candidate, and,...