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retina

(Encyclopedia)retina: see vision; eye. ...

Marburg virus disease

(Encyclopedia)Marburg virus disease, formerly known as Marburg virus hemorrhagic fever, disease caused by infection with a Marburg virus, a filovirus that belongs to a family (Filoviridae) of RNA viruses that also ...

tears

(Encyclopedia)tears, watery secretion of the lacrimal gland, which is located at the outer corner of the eye socket immediately above the eyeball. Tearing, or lacrimation, is a continuous and largely involuntary pr...

McCullers, Carson

(Encyclopedia)McCullers, Carson, 1917–67, American novelist, b. Columbus, Ga. as Lula Carson Smith, studied at Columbia. The central theme of her novels is the spiritual isolation that underlies the human conditi...

pigmentation

(Encyclopedia)pigmentation, name for the coloring matter found in certain plant and animal cells and for the color produced thereby. Pigmentation occurs in nearly all living organisms. Almost all plants synthesize ...

nearsightedness

(Encyclopedia)nearsightedness or myopia, defect of vision in which far objects appear blurred but near objects are seen clearly. Because the eyeball is too long or the refractive power of the eye's lens is too stro...

Hartline, Haldan Keffer

(Encyclopedia)Hartline, Haldan Keffer, 1903–83, American physiologist, b. Bloomsburg, Pa., M.D. Johns Hopkins, 1927. From 1931 to 1949 (except for 1940–41), he was a researcher at the Eldridge Reeves Johnson Fo...

guide dog

(Encyclopedia)guide dog, a dog trained to lead a blind person. The first school for training such dogs was established by the German government after World War I for the benefit of blinded veterans. Schools now exi...

blindness

(Encyclopedia)blindness, partial or complete loss of sight. Blindness may be caused by injury, by lesions of the brain or optic nerve, by disease of the cornea or retina, by pathological changes originating in syst...

Davies, Robertson

(Encyclopedia)Davies, Robertson (William Robertson Davies) dāˈvĭs [key], 1913–95, Canadian writer and editor. After receiving a B.Litt. from Oxford (1938), he joined the Old Vic Theatre Company before returnin...