B
“B” selections in the Glossary of Terms for
Anatomy, Physiology & Pathology of the Human Eye
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- blepharitis
- inflammation, redness, burning, and itching of the eyelids, most commonly in adults, that can be associated with a low grade bacterial infection (staphylococcal blepharitis) or a generalized skin condition (seborrheic blepharitis); caused by abnormalities in oil gland function and an alteration in bacterial colonies that normally live on the skin; treated by gentle scrubbing of the eyelid margins with baby shampoo diluted with water, warm compresses several minutes a day, and sometimes an antibiotic ointment or drop
- binocular vision
- the ability of the visual cortex (located in the occipital lobe of the brain) to combine the impulses it receives from the images on the retinas of both eyes into one single image
- bipolar cells
- intermediary nerve cells in the retina which transmit visual signals from the photoreceptor cells to the ganglion cells
- blind spot
- small area in the visual field corresponding to the retina’s optic disc or optic nerve head (where the optic nerve emerges), where no photoreceptors are present and where there is no sensitivity to light; not noticed with both eyes open because the part of the visual field containing the blind spot of one eye is overlapped by a light-sensitive area in the other eye
- blindness
- transient or permanent inability to see with one or both eyes
- blindness, color
- see color blindness
- blindness, legal
- see legal blindness
- blinking
- closing and opening the eye involuntarily, normally about once every six seconds to replenish the tear film on the surface of the cornea
- block, pupillary
- see pupillary block
- blood cells
- cells normally present in blood, such as red blood cells or white blood cells; may be liberated by a tiny blood vessel broken during a retinal tear or detachment and often observed by the person experiencing the detachment as a shower of floaters
- body, ciliary
- see ciliary body
- Bowman’s membrane
- the thin outer layer of the substantia propria of the cornea, immediately underlying the epithelium
- branch retinal artery occlusion (BRAO)
- blockage of a branch of the central retinal artery; results in the appearance of a whitened retina on both sides of the occluded artery
- branch retinal vein occlusion (BRVO)
- blockage of a branch of the central retinal vein; results in sectoral hemorrhaging and fluid leakage on the retina
- Bruch’s membrane
- the membrane separating the pigment epithelium of the retina and the choriocapilaris of the choroid
- buckle, scleral
- see scleral buckle
- bulbar conjunctiva
- see conjunctiva, bulbar
- bulbar sheath
- the connective-tissue capsule enclosing the eye (except for the cornea), immediately superficial to the sclera; Tenon’s capsule posteriorly, fusing with the sheath of the optic nerve; penetrated by the tendons of the extraocular muscles
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