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Exophthalmos
Exophthalmos, also called proptosis, is the bulging of one or both eyes from the orbit, the bony socket. In adults it is most often caused by Graves disease.
Exotropia
Exotropia, also called wall-eye, is an outward-turning eye misalignment (strabismus). Most common form is intermittent exotropia (75-90% of cases, ~1% prevalence); treated with patching, overminus lenses, or eye muscle surgery.
Exposure keratitis
Exposure keratitis (exposure keratopathy, EK): corneal damage from dryness due to incomplete eyelid closure or poor blinking. Common in ICU patients (pooled prevalence 34%); treated with lubricants, moisture chambers, taping, tarsorrhaphy.
Extraocular muscles
Extraocular muscles: the seven muscles per orbit (four rectus, two oblique, levator palpebrae superioris) that move the eye and lift the eyelid, innervated by cranial nerves III, IV, and VI, organized in global and orbital layers with connective tissue pulleys.
Extrapyramidal system
Extrapyramidal system: historical grouping of basal ganglia, substantia nigra, red nucleus, subthalamic nucleus and descending tracts outside the corticospinal tract; criticized as obsolete, tied to antipsychotic EPS, VMAT2 inhibitor treatments.
Eye
Eye: the organ that focuses light through cornea, pupil, and lens onto the retina, sending signals via the optic nerve to the brain; camera eyes evolved convergently in vertebrates and cephalopods, and vision impairment affects over 2.2 billion people.
Eye Axial Length
Eye axial length: distance from cornea to retina, normally about 23.5 mm (22-24.5 mm). Longer in myopia, shorter in hyperopia; measured by A-scan ultrasound or optical biometry (PCI, SS-OCT) for IOL calculation and myopia control.
Eye discharge
Eye discharge (eye mucus, ICD-11 MC14): mucus, pus, or excess tears from the eye. Normal as sleep crust; abnormal color, texture, or amount signals conjunctivitis, keratitis, blepharitis, stye, or dry eye.
Eye examination
Eye examination: comprehensive adult medical eye evaluation (AAO Preferred Practice Pattern), including history, visual acuity, slit lamp, tonometry, dilation, and fundus exam; differs from simple vision screening, which USPSTF finds insufficient evidence for in older adults.
Eye movement in music reading
Eye movement in music reading studies fixations and saccades over musical notation. Experts show shorter fixations (meta-analytic g = -0.72), read about two beats ahead, and skip notes; other measures vary by task.
Eye movement in reading
Eye movement in reading: saccades and fixations (with 5–20% regressions) by which eyes sample text; covers perceptual span, parafoveal preview, E-Z Reader and SWIFT models, and dyslexia screening.
Eye Movements
Eye movements: saccades, smooth pursuit, vergence, and vestibulo-ocular movements that shift or stabilize gaze on the fovea; controlled by brainstem, superior colliculus, and cerebellum, and measured by eye tracking.
Eye surgery
Eye surgery covers procedures on the eye, from cataract extraction (couching to phacoemulsification, Ridley's 1949 IOL) to LASIK, retinal, and glaucoma surgery; cataract surgery is the leading global blindness treatment.
Eye tracking
Eye tracking, also called gaze tracking, is the measurement of eye position and movement over time, most often by video-oculography, which tracks the pupil and a corneal reflection.
Eyelid
Eyelid (palpebra): the thin skin-muscle fold protecting the eye and spreading the tear film. Key facts: thinnest body skin, tarsal plates, meibomian glands, levator and orbicularis muscles, blepharitis, blepharoplasty.
Eyelid retraction
Eyelid retraction: abnormally high upper or low lower lid position, mostly from thyroid eye disease; causes exposure keratopathy; treated with lubrication, injections, or retractor-lengthening surgery (85% success).
Eyelid trauma
Eyelid trauma is injury to eyelid tissues from blunt or penetrating forces, from black eyes to lacerations, and frequently accompanies eye or orbital injuries needing urgent evaluation.
Face
Face: front of the head, moved by the facial nerve (CN VII) with five motor branches plus taste, salivary, and lacrimal functions; facial nerve palsy, mostly Bell's palsy, is its main disorder.
Facial dysmorphism-lens dislocation-anterior segment abnormalities-spontaneous filtering blebs syndrome
Traboulsi syndrome, also called FDLAB syndrome (OMIM 601552), is an extremely rare autosomal recessive eye disorder caused by ASPH variants, featuring lens dislocation, anterior segment abnormalities, flat cheeks, a beaked nose, and spontaneous filtering blebs.
Facial nerve
Facial nerve (CN VII), seventh cranial nerve with motor and intermediate roots; supplies facial expression muscles, taste anterior two-thirds of tongue, and lacrimal/submandibular/sublingual glands; exits via stylomastoid foramen; Bell's palsy.
Facial nerve paralysis
Facial nerve paralysis, loss of facial muscle movement from facial nerve (CN VII) damage; most often idiopathic Bell's palsy with onset under 72 hours, treated with corticosteroids within 72 hours.
Facial neuritis
Facial neuritis (ICD-11 8B88.3, 顔面神経炎) is inflammation of the facial nerve causing unilateral facial weakness; most often Bell's palsy, treated with corticosteroids within 72 hours, with good prognosis.
Fatal insomnia
Fatal insomnia, fatal familial insomnia (FFI) and sporadic fatal insomnia, fatal thalamic prion disease destroying sleep, caused by PRNP D178N with Met129 in the familial form; death within about a year, no approved treatment.
Federation of European Neuroscience Societies
The Federation of European Neuroscience Societies (FENS) is the main organization for neuroscience in Europe, founded in 1998 and based in Brussels, representing 43 societies and some 20,000 scientists.
Femoral nerve
The femoral nerve is a large lower limb nerve arising from the L2, L3, and L4 lumbar plexus roots and supplying the anterior thigh muscles.
Fencing response
Fencing response, or tonic posturing, is an involuntary posture after traumatic brain injury: one arm extends, the opposite flexes. Linked to the brainstem lateral vestibular nucleus; indicates moderate injury forces but not worse NFL recovery outcomes.
Fever dream
Fever dreams are vivid, bizarre, often negative dreams occurring during fever (oral temperature 100.4°F/38°C or higher). Schredl's studies show they are more bizarre, emotionally intense, heat-themed, and lucid than normal dreams, likely because fever disrupts REM sleep.
Filtering Surgery
Filtering surgery (glaucoma filtration surgery, trabeculectomy) creates a fistula draining aqueous humor to a subconjunctival bleb to lower IOP; developed from De Wecker's 1882 fistula to Cairns' 1968 guarded trabeculectomy, now alongside tube shunts and MIGS.
Fine motor skill
Fine motor skill: coordination of small muscles, bones, and nerves for small, precise hand movements such as pincer grasp and handwriting; also called manual dexterity. Covers corticospinal, cerebellar, and basal ganglia control, pegboard normative scores, developmental milestones, and stroke rehabilitation robotics.
Flaccid paralysis
Flaccid paralysis, also called acute flaccid paralysis (AFP), is loss of muscle tone from lower motor neuron lesions, caused by Guillain-Barré syndrome, poliomyelitis, acute flaccid myelitis, transverse myelitis, botulism, or myopathies, and tracked by WHO polio surveillance.