Human health and medicine

OPM-2

OPM-2 (OPM2, DSMZ ACC 50, Cellosaurus CVCL_1625) is a human multiple myeloma plasma cell line established in 1982 from the peripheral blood of a 56-year-old woman, IgG lambda, carrying t(4;14) with activating FGFR3 K650E and homozygous TP53 R175H.

Opnurasib

Opnurasib (JDQ443, NVP-JDQ-443) is a Novartis investigational covalent KRAS G12C inhibitor binding the Switch II pocket with a novel H95-sparing mode, in phase III (KontRASt-02) versus docetaxel in NSCLC.

Oportuzumab monatox

Oportuzumab monatox (Vicinium, Vicineum, VB4-845) is an investigational anti-EpCAM scFv fused to Pseudomonas exotoxin A, given intravesically for BCG-unresponsive bladder cancer; FDA CRL and EMA withdrawal in 2021.

Opportunistic infection

Opportunistic infection (OI): infections more frequent or severe in immunocompromised people, especially with HIV, cancer, or transplants; examples include PCP, tuberculosis, toxoplasmosis, candidiasis, and CMV retinitis.

Opportunistic osteoporosis screening

Opportunistic osteoporosis screening identifies low bone mineral density and vertebral fractures on CT scans already acquired for unrelated reasons, adding no cost, time, or radiation.

Opportunistic salpingectomy

Opportunistic salpingectomy is the removal of both fallopian tubes during a pelvic operation a woman is already having, to prevent ovarian cancer without causing menopause.

Oppositional defiant disorder

Oppositional defiant disorder (ODD), also called oppositional disorder, is a childhood behavior disorder of angry, argumentative, defiant, and vindictive behavior toward authority figures lasting at least 6 months, treated mainly with parent management training and CBT.

OPQRST

OPQRST is a mnemonic used in emergency medicine, nursing, and prehospital care to structure the history of a patient's pain, covering Onset, Provocation, Quality, Region, Severity, and Time, and taught alongside SAMPLE.

Oprelvekin

Oprelvekin (Neumega), recombinant human interleukin-11, was the first FDA-approved drug (1997) for chemotherapy-induced thrombocytopenia; withdrawn from the US market for fluid retention, arrhythmias, and cost.

Opsin

Opsin: light-sensitive seven-transmembrane GPCR apoprotein that binds retinal via a Schiff base; forms rhodopsin and visual pigments (Type II animal opsins), distinct from Type I microbial opsins used in optogenetics.

Opsismodysplasia

Opsismodysplasia (OPSMD, OMIM 258480) is a rare autosomal recessive skeletal dysplasia with severely delayed bone ossification, short limbs, small hands and feet, and characteristic facial features; biallelic INPPL1 variants explain about 60% of cases.

Opsoclonus-myoclonus syndrome

Opsoclonus-myoclonus syndrome (Kinsbourne syndrome, dancing eye syndrome) is a rare neuroinflammatory disorder with opsoclonus, myoclonus, ataxia, and sleep and behavioral disturbance, usually paraneoplastic from neuroblastoma in children and lung or breast cancer in adults.

Opsonophagocytic killing assay

The opsonophagocytic killing assay (OPKA) is an in vitro immunology assay measuring how antibodies and complement enable phagocytes to kill bacteria, used to evaluate functional immunity from bacterial vaccines.

Optic atrophy

Optic atrophy, better termed optic neuropathy, is death of retinal ganglion cell axons causing a pale optic disc and vision loss; causes include glaucoma, compression, ischemia, toxins, and inherited mitochondrial disorders like LHON and OPA1-related dominant optic atrophy.

Optic atrophy-intellectual disability syndrome

Optic atrophy-intellectual disability syndrome, or Bosch-Boonstra-Schaaf optic atrophy syndrome (BBSOAS, OMIM 615722), is a rare autosomal dominant NR2F1 disorder with developmental delay, intellectual disability, optic atrophy, hypotonia, and seizures.

Optic chiasm

Optic chiasm: brain-base structure where optic nerves partially decussate, nasal retinal fibers crossing (about 53:47 crossed-to-uncrossed), enabling binocular vision; pituitary tumor compression causes bitemporal hemianopia.

Optic disc

Optic disc (optic nerve head): retinal site where ganglion cell axons exit as the optic nerve; no photoreceptors, so it forms the blind spot; central retinal vessels pass through it; key glaucoma and papilledema landmark.

Optic disc dysplasia

Optic disc dysplasia (ICD-11 LA13.73) is a congenital malformation in which the optic disc is deformed and fits no recognized diagnostic category; related excavated anomalies include morning glory disc anomaly, optic disc pit, and coloboma, with risks of retinal detachment and systemic associations such as papillorenal syndrome.

Optic disc pit

Optic disc pit (ODP, optic nerve pit): rare congenital optic nerve head excavation, about 1 in 11,000, usually inferotemporal and unilateral; causes maculopathy with retinal fluid in 25–75% of eyes, treated mainly by vitrectomy.

Optic disc swelling

Optic disc swelling (disc edema, papilledema when from raised intracranial pressure) is axoplasmic-stasis swelling of the optic nerve head, distinguished from pseudoedema such as optic disc drusen by OCT and fundus findings.

Optic nerve

Optic nerve (cranial nerve II, nervus opticus): the CNS white-matter tract of about 1.2 million retinal ganglion cell axons carrying vision from retina to chiasm and brain; myelinated by oligodendrocytes, afferent limb of the light reflex, limited regeneration.

Optic nerve avulsion

Optic nerve avulsion (ONA, Evulsio nervi optici) is traumatic disinsertion of optic nerve fibers at the lamina cribrosa after blunt ocular trauma; rare, causes permanent severe vision loss, no effective treatment.

Optic neuritis

Optic neuritis, inflammatory optic neuropathy causing subacute vision loss and eye pain in young adults; typical (idiopathic or MS) versus atypical AQP4-IgG NMOSD and MOGAD forms, diagnosed clinically with OCT and MRI support.

Optic pathway glioma

Optic pathway glioma (visual pathway glioma) is a rare, slow-growing, usually WHO grade I pilocytic astrocytoma of the optic nerve, chiasm, or tract, mostly in children under 10, often linked to NF1, treated by observation, chemotherapy, or targeted MEK inhibitors.

Optical biometry

Optical biometry is a non-contact ophthalmic technique that uses infrared light to measure the eye's axial length, replacing ultrasound for intraocular lens power calculation before cataract surgery.

Optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) is a noninvasive imaging method that visualizes blood flow in the retinal and choroidal microvasculature without dye, commercially available since 2014.

Optical frequency domain imaging

Optical frequency domain imaging (OFDI), also known as swept-source OCT, is a high-speed form of optical coherence tomography introduced in 2003, used in coronary imaging and gastrointestinal endoscopy.

Optical Imaging

Optical imaging: biomedical imaging using light interaction (scattering, absorption, fluorescence) with tissue, from microscopy to OCT, DOT, and photoacoustic methods; defined by MeSH in 2013, limited by scattering to a depth-resolution trade-off, with FDA-approved agents like ICG.

Optician

Optician (dispensing optician): an eye care professional who fits and dispenses eyeglasses and contact lenses from optometrist or ophthalmologist prescriptions, without diagnosing eye disease; distinct from optometrists and ophthalmologists, regulated in the UK by the General Optical Council.