The student's guide to diseases of the eye . The spotitself is generally small andcircumscribed; it usuallybursts forwards, and is con-verted into an ulcer, but itmay perforate the posteriorsurface of the cornea. Thereis always some haziness ofthe entire cornea, and thepurulent infiltration may, ifthe case do badly, spread andinvolve almost its whole ex-tent. Hypopyon signifies a collection of pus or puro-lymph at the lowest part of the an-terior chamber; its upper boundaryis usually, but not always, level (). It may occur with any acuteulcer, whether deep or not, which isaccompanied by
The student's guide to diseases of the eye . The spotitself is generally small andcircumscribed; it usuallybursts forwards, and is con-verted into an ulcer, but itmay perforate the posteriorsurface of the cornea. Thereis always some haziness ofthe entire cornea, and thepurulent infiltration may, ifthe case do badly, spread andinvolve almost its whole ex-tent. Hypopyon signifies a collection of pus or puro-lymph at the lowest part of the an-terior chamber; its upper boundaryis usually, but not always, level (). It may occur with any acuteulcer, whether deep or not, which isaccompanied by purulent infiltrationof the surrounding cornea ; or withcorneal abscess; or with any cornealulcer, chronic or acute, in which thereis iritis. The pus may be derivedeither from an abscess breakingthrough the posterior surface of thecornea, or from suppuration of theepithelium covering Descemets mem-brane, or from the surface of the iritis now and then gives riseto hypopyon. The diameter of theanterior chamber is a little greater. Fig. 44.— a. Abscess. b. Onyx. 98 DISEASES OF THE CORNEA than the apparent diameter of the clear cornea, andthus a very small hypopyon may be hidden behindthe overlapping edge of the sclerotic. In many cases of severe corneal suppuration (a,Fig. 44) the pus sinks down between the lamellae ofthe cornea (b). To this condition the term onyx isapplied, and should be limited, though it is some-times used in other senses. The term, however, mayvery well be discarded. Onyx and hypopyon oftencoexist, and then the distinction between them canhardly be made without tapping the anterior if liquid will, but onxyx will not, changeits position if the patient lies down ; as however, thepus of a hypopyon is often gelatinous or fibrinous,this test loses much of its value. The distinction cansometimes be made by means of oblique illumination,the cornea being clear in front of a hypopyon. Treatment of ulcers of the cornea. The principles of
Size: 999px × 2502px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksu, booksubjecteye, booksubjectophthalmology
