Human health and medicine

Ocular pain

Ocular pain (eye pain, ICD-10 H57.1, ICD-11 MC18) is pain in or around the eye, from corneal abrasion to glaucoma, uveitis, scleritis, referred headache, or neuropathic ocular pain; red flags include vision loss and proptosis.

Ocular prosthesis

Ocular prosthesis (artificial eye, glass eye): wearable device replacing lost eye tissue after enucleation, evisceration, or congenital anophthalmia; made of cryolite glass or PMMA, fitted 5-8 weeks post-surgery, polished yearly, increasingly 3D printed.

Ocular Refraction

Ocular refraction (eye refraction, retinoscopy, autorefraction) is the clinical measurement of the eye's refractive error to derive an eyeglass or contact lens prescription, by subjective, objective, or cycloplegic methods.

Ocular siderosis

Ocular siderosis (siderosis bulbi): iron deposition in eye tissues from a retained iron-containing intraocular foreign body, usually after hammering trauma; causes heterochromia, cataract, retinal degeneration; treated by foreign body removal.

Ocular surface squamous neoplasia

Ocular surface squamous neoplasia (OSSN), also called conjunctival intraepithelial neoplasia spectrum, is a dysplasia-to-invasive-squamous-cell-carcinoma continuum of the conjunctiva and cornea, linked to UVB, HPV, and HIV, treated by excision or topical interferon, 5-FU, or mitomycin C.

Ocular tilt reaction

Ocular tilt reaction (OTR): triad of skew deviation, ocular torsion, and head tilt toward the lower eye, from otolithic pathway imbalance; coined by Westheimer and Blair, 1975.

Oculo-palato-cerebral syndrome

Oculo-palato-cerebral syndrome, also called oculo-palato-cerebral dwarfism (OMIM 257910), is an extremely rare autosomal recessive disorder with persistent hyperplastic primary vitreous, microphthalmia, microcephaly, cleft palate, small hands and feet, and intellectual disability; about five cases reported.

Oculoauriculofrontonasal syndrome

Oculoauriculofrontonasal syndrome (OAFNS) is a rare congenital disorder combining frontonasal dysplasia, such as widely spaced eyes, with ear and facial defects of the oculoauriculovertebral spectrum; its cause is unknown.

Oculocerebral hypopigmentation syndrome, Cross type

Oculocerebral hypopigmentation syndrome, Cross type (Cross syndrome, Kramer syndrome, Cross-McKusick-Breen syndrome, OMIM 257800) is an extremely rare autosomal recessive disorder with skin and ocular hypopigmentation, microphthalmia, intellectual disability, spastic tetraplegia, and athetoid movements, first described in 1967 in an Amish family.

Oculocerebrocutaneous syndrome

Oculocerebrocutaneous syndrome, also called Delleman-Oorthuys syndrome, is a rare congenital disorder combining eye, brain, and skin malformations, first described in 1981 in around 40 reported cases, mostly in boys.

Oculocerebrorenal syndrome of Lowe

Oculocerebrorenal syndrome of Lowe, or Lowe syndrome (OCRL gene, Xq25), a rare X-linked disorder with congenital cataracts, hypotonia, intellectual disability, and renal Fanconi syndrome; allelic milder Dent disease 2.

Oculocutaneous albinism type 1

Oculocutaneous albinism type 1 (OCA1, tyrosinase-negative albinism) is an autosomal recessive TYR-gene disorder with subtypes OCA1A, OCA1B, and temperature-sensitive OCA1-TS, prevalence about 1 in 40,000.

Oculocutaneous albinism type 2

Oculocutaneous albinism type 2 (OCA2), also called P gene albinism, is an autosomal recessive albinism caused by OCA2 gene mutations on chromosome 15; the most common albinism worldwide, with prevalence about 1 in 36,000 in Europeans and up to 1 in 1,000 in parts of sub-Saharan Africa.

Oculocutaneous albinism type 3

Oculocutaneous albinism type 3 (OCA3, rufous albinism, OMIM 203290) is an autosomal recessive albinism from TYRP1 mutations on 9p23, prevalent at 1 in 8,500 in Africa, with mild red-bronze skin, ginger-red hair, and mild ocular features.

Oculocutaneous albinism type 4

Oculocutaneous albinism type 4 (OCA4), also called SLC45A2-related oculocutaneous albinism, is a rare autosomal recessive albinism affecting about 1 in 100,000 people and is the most common type in Japan.

Oculocutaneous albinism type 5

Oculocutaneous albinism type 5 (OCA5, OMIM 615312) is an autosomal recessive albinism mapped to chromosome 4q24 with the gene unidentified; reported in a consanguineous Pakistani family, causing white skin, golden hair, nystagmus, and reduced vision.

Oculocutaneous albinism type 6

Oculocutaneous albinism type 6 (OCA6) is a rare autosomal recessive albinism caused by variants of the SLC24A5 gene, producing pale skin, light hair, and reduced vision.

Oculocutaneous albinism type 7

Oculocutaneous albinism type 7 (OCA7, OMIM 615179) is a very rare autosomal recessive albinism caused by LRMDA (C10orf11) variants on 10q22.2-q22.3, with predominantly ocular features; 18 patients described, proposed rename ocular albinism type 2.

Oculocutaneous albinism type 8

Oculocutaneous albinism type 8 (OCA8, OMIM 619165) is an ultra-rare autosomal recessive albinism caused by DCT (dopachrome tautomerase) variants, with mild skin and hair hypopigmentation, nystagmus, foveal hypoplasia, and iris transillumination.

Oculodental syndrome, Rutherfurd type

Oculodental syndrome, Rutherfurd type (Rutherfurd syndrome, ORPHA:2709, OMIM 180900) is a rare autosomal dominant disorder with gingival fibromatosis, failure of tooth eruption, and bilateral corneal dystrophy; causative gene unknown.

Oculodentodigital dysplasia

Oculodentodigital dysplasia (ODDD, Meyer-Schwickerath syndrome) is a rare autosomal dominant GJA1/connexin 43 disorder affecting eyes, teeth, and digits, with syndactyly type 3, microcornea, and neurologic involvement in about 30 percent.

Oculoectodermal syndrome

Oculoectodermal syndrome (Toriello-Lacassie-Droste syndrome, OMIM 600268) is a very rare mosaic RASopathy caused by somatic KRAS mutations, defined by aplasia cutis congenita and epibulbar dermoids with variable bone, brain, and heart anomalies.

Oculofaciocardiodental syndrome

Oculofaciocardiodental (OFCD) syndrome, or syndromic microphthalmia 2, is a rare male-lethal X-linked dominant disorder caused by BCOR null mutations, featuring congenital cataracts, microphthalmia, heart defects, and canine radiculomegaly in females.

Oculogastrointestinal muscular dystrophy

Oculogastrointestinal muscular dystrophy (OGIMD), or visceral myopathy with familial external ophthalmoplegia, is an extremely rare autosomal recessive neuromuscular disease with childhood-onset ptosis, ophthalmoplegia, chronic diarrhea, malnutrition, and intestinal pseudo-obstruction; OMIM 277320.

Oculogastrointestinal-neurodevelopmental syndrome

Oculogastrointestinal-neurodevelopmental syndrome (OGIN), also called OGIN syndrome, is a rare autosomal recessive CAPN15-related disorder with microphthalmia, coloboma, imperforate anus, horseshoe kidney, cardiac defects, hearing loss, and developmental delay.

Sep 29, 2026

Oculography

Oculography is the clinical recording of eye movements, including saccades, smooth pursuit, and nystagmus, to assess vestibular, neurological, and ocular motor disorders, chiefly by electro-oculography and video-oculography.

Oculogyric crisis

Oculogyric crisis (OGC), also called vertical spasm of gaze, is a rare acute dystonic reaction causing sustained conjugate upward eye deviation, usually from neuroleptic drugs or dopamine-related neurometabolic disorders, treated with anticholinergics.

Oculomotor nerve

Oculomotor nerve (cranial nerve III): midbrain motor nerve supplying four extraocular muscles, levator palpebrae, and pupil constriction via Edinger-Westphal fibers; palsy causes ptosis, diplopia, down-and-out eye, pupil-involving from aneurysm or herniation.

Oculomotor nerve palsy

Oculomotor nerve palsy (third cranial nerve palsy, CN III palsy) causes ptosis, diplopia, and a down-and-out eye; pupil involvement signals aneurysm and urgent imaging, while pupil sparing suggests microvascular ischemia.