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 (rotates the top of the eye inward, turns the front of the eye downward, and turns the front of the eye outward)

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 (turns the front of the eye upward, rotates the top of the eye inward, and turns the front of the eye inward)

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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