All articles starting with R
22,461 articles
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 ganglion cell
Retinal ganglion cells (RGCs) are the retina's sole output neurons, sending visual information through the optic nerve; about 1.2 million in humans, roughly 30 types in mouse, feature detectors lost in glaucoma.
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 implant
A retinal implant is a medical device that restores partial vision to people blinded by retinitis pigmentosa or macular degeneration by electrically stimulating surviving retinal neurons.
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 epithelial cell
Retinal pigment epithelial cell (RPE, CL:0002586): epithelial cell of the retinal pigmented epithelium, a single pigmented layer between photoreceptors and choroid that phagocytoses outer segments, recycles vitamin A, and forms the outer blood-retinal barrier.
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.
RetinaNet
RetinaNet is a one-stage object detection model introduced in 2017 by Tsung-Yi Lin and colleagues at Facebook AI Research, known for focal loss, which down-weights easy background examples during training.
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.
Retinitis punctata albescens
Retinitis punctata albescens (RPA, OMIM 136880) is a rare progressive inherited retinal dystrophy with white fundus dots and childhood night blindness, usually caused by RLBP1 mutations and related to retinitis pigmentosa.
Retinoblast
Retinoblast: multipotent embryonic retinal progenitor cell of the optic cup that generates all retinal neurons and Müller glia; distinct from retinoblastoma, the Rb-gene childhood tumor.
Retinoblastoma
Retinoblastoma is a childhood cancer of the retina, caused by RB1 tumor suppressor inactivation (Knudson two-hit hypothesis) or rarely MYCN amplification. Key sign is leukocoria; survival ranges from 99.5% in high-income to 57.3% in low-income countries.