S
“S” selections in the Glossary of Terms for
Anatomy, Physiology & Pathology of the Human Eye
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- saccade
- an eye movement in which the eyes jump from one point to another, as from one word to the next while reading or around a room when searching for something
- sarcoidosis
- a rare, chronic, autoimmune disease of unknown cause that is characterized by the formation of nodules resembling true tubercles, especially in the lymph nodes, lungs, liver, eyes, bones, skin, joints, kidneys, and spleen
- Schlemm, canal of
- see canal of Schlemm
- Schwalbe’s line
- the demarcation between the cornea and the sclera; the endpoint of Descemet’s membrane
- sclera
- the dense fibrous opaque white outer coat enclosing the eyeball, except the part covered by the cornea
- scleral buckle
- a silicone implant or flexible band placed around the equator of the eye which “squeezes” the eye inward and to counterbalance any force pulling the retina out of place
- scleral spur
- the protrusion of the sclera to which the trabecular fibers attach anteriorly and the iris root attaches posteriorly
- sclerosis, multiple (MS)
- see multiple sclerosis (MS)
- scotoma
- a blind or dark spot in the visual field
- scotopic range
- the dimly-illuminated range of light, below 0.034 cd/m˛ (candela per meters squared), in which the rods of the retina respond well but the cones of the retina respond poorly or not at all; most commonly present at night
- silicone plug
- see plug, silicone
- sinusitis
- inflammation of a sinus of the skull
- Sjogren’s syndrome
- a chronic inflammatory autoimmune disease that affects especially older women; characterized by dryness of mucous membranes, especially of the eyes and mouth, and by infiltration of the affected tissues by lymphocytes; often associated with rheumatoid arthritis
- spasm, ciliary
- see ciliary spasm
- spectacles
- see eyeglasses
- spondylitis, ankylosing
- see ankylosing spondylitis
- strabismus
- heterotropia or tropia; inability to attain or maintain binocular vision due to some type of muscle imbalance in one eye, causing that eye to turn in, out, up, or down relative to the other eye; can be “intermittent” (occurring sometimes), “constant” (occurring all the time), and/or “alternating” (occurring sometimes with one eye and sometimes with the other eye, whether intermittently or constantly)
- stress, nearpoint
- see nearpoint stress
- stroma, corneal
- substantia propria; lamellae (layers) of regularly arranged collagen fibers in the cornea, the parallel fibers in each lamella aligned at an orientation different from those of the fibers in the appropriately spaced layers above and below it such that corneal transparency is maintained; comprises 90% of the cornea’s thickness
- stroma, iridial
- thick, highly vascular central layer of the iris containing delicate collagenous fibers intermixed with varying proportions of pigmented and nonpigmented cells, the amounts of the latter which provide the iris with its degree of color
- sty(e)
- see hordeolum
- subconjunctival hemorrhage
- see hemorrhage, subconjunctival
- substantia propria
- the layer of lamellated transparent fibrous connective tissue that makes up the bulk of the cornea of the eye
- superior oblique muscle
- an extraocular muscle in the orbit, originating in the annulus of Zinn, which loops through the trochlea before inserting into the sclera; innervated by the trochlear nerve (cranial nerve IV); intorts, depresses, and abducts the eye
- superior rectus muscle
- an extraocular muscle in the orbit, originating in the annulus of Zinn; innervated by the oculomotor nerve (cranial nerve III); elevates, intorts, and adducts the eye
- suspensory ligaments
- see zonules of Zinn
- syphilis
- a chronic contagious, usually venereal and often congenital disease that is caused by a spirochete of the genus Treponema (T. pallidum) and if left untreated produces chancres, rashes, and systemic lesions in a clinical course with three stages continued over many years
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