Human health and medicine

Retifanlimab

Retifanlimab (Zynyz, INCMGA00012) is a humanized IgG4 anti-PD-1 checkpoint inhibitor by Incyte, FDA-approved for Merkel cell carcinoma (2023) and anal canal squamous cell carcinoma (2025).

Retiform hemangioendothelioma (RH), a rare intermediate-malignancy vascular tumor first delineated by Calonje in 1994, forms slow-growing hobnail-lined arborizing skin lesions of the distal extremities; it recurs locally in about 50-60% of cases but rarely metastasizes.

Retina

The retina is the light-sensitive neural tissue lining the back of the eye, containing rods and cones plus bipolar, horizontal, amacrine, and ganglion cells; the fovea is rod-free with peak cone density, and OCT imaging and AAV gene therapy are central clinical advances.

Retina bipolar cell

Retinal bipolar cells are retinal interneurons relaying photoreceptor input to ganglion cells; about 12 primate and 13+ mouse types, split into ON (mGluR6) and OFF pathways.

Retina horizontal cell

Retina horizontal cells are inhibitory interneurons in the inner nuclear layer that feed back to photoreceptors and forward to bipolar cells, creating center-surround receptive fields; primates have H1 and H2 types, mice one, zebrafish four.

Retinal

Retinal (11-cis-retinal), the aldehyde of vitamin A, is the universal light-absorbing chromophore of rhodopsin and cone pigments; photoisomerized to all-trans and regenerated by the RPE65 visual cycle and a Müller-cell cone cycle.

Retinal artery occlusions

Retinal artery occlusions (CRAO, BRAO, ophthalmic artery occlusion) are embolic blockages of retinal arteries causing sudden painless vision loss; treated as acute stroke with urgent stroke-center referral, though no proven vision-restoring therapy exists.

Retinal atrophy

Retinal atrophy: wasting of the retinal pigment epithelium and neurosensory retinal cells from inherited, age-related, toxic, or secondary causes; includes geographic atrophy, ARCA, and gyrate atrophy, classified by OCT consensus terms cRORA and iRORA.

Retinal breaks without detachment

Retinal breaks without detachment (ICD-11 9B73.4): full-thickness retinal tears, holes, or dialyses without retinal separation. Symptomatic horseshoe tears need treatment; asymptomatic breaks are usually observed.

Retinal cavernous hemangioma

Retinal cavernous hemangioma (CHR, cavernous hemangioma of the retina) is a rare benign retinal vascular hamartoma with grape-like saccular clusters, usually unilateral and asymptomatic; intracranial hemangiomas occur in 14% of cases.

Retinal cell

Retinal cell: any of the neuron and glia types of the retina, including rods, cones, horizontal, bipolar, amacrine, and ganglion cells; over 130 cell types, with rods outnumbering cones 20-30 to 1 in humans.

Retinal cysts

Retinal cysts (ICD-11 9B73.2; 網膜嚢胞) are closed sacs in the retina, congenital or acquired, including ora serrata and parasitic cysts; distinct from retinoschisis and microcystoid degeneration, imaged mainly by OCT.

Retinal detachment

Retinal detachment: separation of the retina from the retinal pigment epithelium, an ophthalmic emergency. Rhegmatogenous type is most common; Gonin's 1919 break theory and ignipuncture founded modern repair; over 90% single-surgery success today.

Retinal detachment with retinal break

Retinal detachment with retinal break (rhegmatogenous retinal detachment, RRD): retina separates from the retinal pigment epithelium because a tear lets vitreous fluid pass under it. Treated by pneumatic retinopexy, scleral buckling, or vitrectomy; modern reattachment success exceeds 90%.

Retinal gene therapy using lentiviral vectors

Retinal gene therapy using lentiviral vectors: EIAV- and HIV-1-derived integrating retroviral vectors carrying genes up to ~8 kb, targeting RPE and photoreceptors via subretinal injection; used in Stargardt (SAR422459) and Usher 1B (UshStat) trials, distinct from non-integrating AAV.

Retinal haemorrhage

Retinal haemorrhage (retinal hemorrhage) is bleeding into the retina, classified by layer (flame, dot-and-blot, preretinal, subretinal, vitreous). Causes include diabetes, hypertension, vein occlusion, trauma, and abusive head trauma in infants; diagnosis uses OCT and angiography.

Retinal ischaemia

Retinal ischaemia is an insufficient blood supply to the retina, the light-sensitive tissue lining the back of the eye, and a driving factor in diabetic retinopathy and retinal vein occlusion.

Retinal macular dystrophy type 2

Retinal macular dystrophy type 2 (MCDR2, OMIM 608051), also called PROM1-related or autosomal dominant bull's-eye macular dystrophy, is a rare dominant macular dystrophy causing slowly progressive bull's eye maculopathy with mild vision loss.

Retinal migraine

Retinal migraine (ocular migraine), ICHD-3 code 1.2.4, is a rare migraine subtype with fully reversible monocular visual disturbance (scotomata, scintillations, blindness) followed within 60 minutes by headache; a diagnosis of exclusion, treated with verapamil, avoiding triptans and beta-blockers.

Retinal oedema

Retinal edema, also called retinal edema, is fluid buildup within the retina that causes blurring and distortion of central vision, most often from diabetic retinopathy, retinal vein occlusion, or wet age-related macular degeneration.

Retinal pigment epithelium

Retinal pigment epithelium (RPE): pigmented monolayer behind the retina supporting photoreceptors via phagocytosis, the visual cycle, and the outer blood-retinal barrier; its degeneration drives AMD, and stem cell-derived RPE transplants are in early trials.

Retinal telangiectasis

Retinal telangiectasis is a rare anomaly of the retinal capillaries marked by dilated, tortuous vessels, aneurysms, and leakage, spanning entities from Coats disease to idiopathic macular telangiectasia.

Retinal vascular occlusions

Retinal vascular occlusions (ICD-11 9B74) are blockages of retinal arteries or veins, mainly RVO (CRVO, BRVO) and RAO. Prevalence 0.77% ages 30–89; anti-VEGF is first-line for RVO macular edema; acute RAO requires stroke-center referral.

Retinal vasculitis

Retinal vasculitis: inflammatory infiltration of retinal vessel walls, idiopathic or secondary to infections (tuberculosis, herpes), Behçet disease, sarcoidosis, or systemic vasculitis; diagnosed clinically with angiography, treated by cause.

Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations

RVCL-S (also CRV, HERNS, HVR) is a rare autosomal dominant small vessel disease caused by C-terminal TREX1 mutations, causing retinopathy, brain lesions, liver and kidney disease, onset ages 30-50, premature death, no cure, crizanlizumab trials.

Retinal venous occlusions

Retinal venous occlusions (RVO): blockages of retinal veins, central (CRVO) or branch (BRVO), causing sudden painless vision loss and macular edema; anti-VEGF injections are first-line treatment.

Oct 15, 2026

Retinex

Retinex is a theory of human color vision and a family of image-enhancement algorithms, proposed by Edwin H. Land and John J. McCann in 1971.

Retinitis

Retinitis: inflammation primarily of the retina, usually infectious and necrotizing (CMV, HSV/VZV, Toxoplasma, syphilis). CMV retinitis affects AIDS patients with CD4 <50 cells/µL; HAART cut incidence over 80%.

Retinitis pigmentosa

Retinitis pigmentosa (RP), hereditary retinal dystrophy, is a group of inherited retinal diseases causing progressive photoreceptor degeneration, night blindness, tunnel vision, and legal blindness; over 130 genes involved, no cure, vitamin A and emerging gene therapies studied.