Retina

RETINA Ding JianGuang

Anatomy of Retina: Thin, semitransparent, inner layer of the wall of the eyeball.  Anterior margin: ora serrata ciliary body Posterior margin: round the optic disc Outside: closely neighbors with the choroid Inside: vitreous 

Anatomy of Retina (Histology): 

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10 layers, Retina pigment epithelium(RPE) are firmly bound to Bruch’s membrane (basement membrane of the RPE, its outside is choroid), RPE : tidy arranged, hexagonal cells, transport nourishment from the choroid to the external layer of the retina(5 layers) Photoreceptor layer ( rods and cones) separate from the RPE layer --Retina detachment. Visual message visual never pulse.transmitted by 3 neurons: Photoreceptor - bipolar cell – ganglion cell. Photoreceptor cells : Rods (function)—dark vision Cones—strong light and color vision

Anatomy of Retina: 

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Macula: the center of the posterior retina no blood vessel, responsible for the best visual acuity and color vision. Fovea: the center of the macula only cones Optic disc: 4mm lateral to the fovea no photoreceptor cells The retinal artery: from ocular artery The retinal vein Peripheral retina: mainly rod photoreceptors, for peripheral and night vision.

Examine the Retina:    

Direct ophthalmoscopy Indirect ophthalmoscopy Goldman three-mirror lens Fundus photography

Examine the Retina: Fundus Fluorescein Angiography(FFA)—take pictures  Indocyanine green angiography(ICG)  Electrophysiologic testing ERG (Electroretinography) —F-ERG : reflect the whole retina (various retinopathies) —P-ERG : reflect never ganglion cell layer EOG (Electro-oculography)—reflect the diseases of RPE VEP (Visual Evoked Response)— above the ganglion cells 

Diseases of the Retina:  Diseases

of the macula:

Age- related macular degeneration ( AMD) Central serous chorioretinopathy ( CSC)

 Diseases

of the peripheral retina:

Retina detachment (RD)

 Retinal

vascular diseases:

Retinal artery occlusion (Central , CRAO; Branch , BRAO) Retinal vein occlusion (CRVO; BRVO) Diabetic retinopathy (DR)

 Tumors

of the retina:

Retinoblastoma(RB)

Age- related macular degeneration ( AMD)  Age-related

macular degeneration is the leading cause of permanent blindness in the elderly. The exact cause is unknown, but the incidence increases with each decade over age 50.  classified into two groups: nonexudative ("dry") and exudative ("wet").

Nonexudative Macular Degeneration  Nonexudative

age-related macular degeneration is characterized by variable degrees of atrophy and degeneration of the outer retina, retinal pigment epithelium, Bruch's membrane and choriocapillaris.  Drusen are discrete, round, yellow-white deposits of variable size beneath the pigment epithelium and are scattered throughout the macula and posterior pole.

Nonexudative age-related macular degeneration. Typical signs include drusen (arrow) and geographic central atrophy (arrowhead).

Nonexudative Macular Degeneration  In

addition to drusen, clumps of pigment irregularly dispersed within depigmented areas of atrophy may progressively appear throughout the macula.  There is no generally accepted means of preventing of this type of macular degeneration.

Exudative Macular Degeneration  the

majority of patients who experience severe vision loss from this disease do so from the development of subretinal neovascularization and related exudative maculopathy  Ingrowth of new vessels from the choroid into the subretinal space is the most important change that predisposes patients with drusen to macular detachment and irreversible loss of central vision.

Exudative age-related macular degeneration. A typical finding is the intraretinal serous fluid (arrows), which is extravasating from the choroidal neovascularization.

a Fluorescein angiogram. A classic choroidal neovascularization is visible under the fovea (arrows). This is therefore a late, exudative stage of age-related macular degeneration.

Exudative Macular Degeneration Treatment a

well-defined extrafoveal (≥200um from the center of the foveal avascular zone) subretinal neovascular membrane----laser photocoagulation

Central Serous Chorioretinopathy  Central

serous chorioretinopathy is characterized by serous detachment of the sensory retina as a consequence of focal leakage of fluid from the choriocapillaris through a defect in the retinal pigment epithelium.  Young to middle-aged men, may be related to life stress events.

Central Serous Chorioretinopathy

Central Serous Chorioretinopathy A

sudden onset of blurred vision, micropsia, metamorphopsia, and central scotoma.  Visual acuity is often moderately decreased.  FFA: Fluorescein dye leaking from the choriocapillaris may accumulate below the pigment epithelium or sensory retina, resulting in a variety of patterns including the well-recognized smokestack configuration.

Central Serous Chorioretinopathy

Central Serous Chorioretinopathy  80%

of eyes undergo spontaneous resorption of subretinal fluid and recovery of normal visual acuity within 6 months.  Many patients have a mild permanent visual defect.  Argon laser photocoagulation shortens the duration of the sensory detachment and hastens the recovery of central vision, but can not reduce the chance of permanent loss of visual function.

Myopic Macular Degeneration  Pathologic

myopia is one of the leading causes of blindness and characterized by progressive elonggation of the eye with subsequent thinning and atrophy of the choroid and pigment epithelium in the macular.

Myopic Macular Degeneration  Perpapillary

chorioretinal atrophy and linear breaks in Bruch’s membrane are characteristic findings on ophthalmoscopy.  A characteristic lesion of this disease is a raised, circular, pigmented macular lesion called a Fuchs spot.

Myopic Macular Degeneration  Most

patients are in the fifth decade when the degenerative macular changes cause a slowly progressive loss of vision; rapid loss of visual acuity is usually caused by serous and hemorrhagic macular degeneration overlying a subretinal neovascular membrane.

Myopic Macular Degeneration  Peripheral

retinal findings may include paving stone degeneration, pigmentary degeneration, and lattice degeneration.  Some retinal breaks will progress to Rhegmatogenous retinal detachment.

Macular Hole A

macular hole is a partial or full-thickness absence of the sensory retina in the macula. Tangential traction from epiretinal vitreous cortex plays an important role in the pathogenesis.

Retinal detachment:  Retinal

detachment:

Separation of the sensory retina (photoreceptors and inner tissue layers) from the underlying retinal pigment epithelium (RPE).

Retinal detachment:  Three   

main types:

Rhegmatogenous detachment Traction detachment Serous or hemorrhagic detachment

Rhegmatogenous retinal detachment:  Most

common of the three types

 Tear: full-thickness break in sensory retina

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horseshoe tear,round atrophic hole,etc Blurred vision: one part(nasal 、 temporal) extend Variable degrees of vitreous traction

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Liquefied vitreous through the sensory retina

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defect(tear) into the subretinal space Usually accompanied by a posterior vitreous detachment Myopia,ocular trauma, aphakia associated with this type

Posterior vitreous detachment:    

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Normal vitreous is bounded by the retina,optic disk,pars plana, zonule, and lens. It’s firmly attached to the retina and pars plana near the ora serrata Support the retina With age,the center of the vitreous may undergo syneresis and become filled with liquid.The liquid contents of the cavity can migrate into the preretinal space .The heavier vitreous gel collapses. Vitreous shrinkage: Vitreoretinal traction—retinal tear

Rhegmatogenous retinal detachment treatment: Close the hole(key)  Cryotherapy  Laser photocoagulation  surgery

Retinitis Pigmentosa  Retinitis

pigmentosa is a group of hereditary retinal degenerations characterized by progressive dysfunction of the photoreceptors and associated with progressive cell loss and eventual atrophy of several retinal layers.

Retinitis Pigmentosa  This

disease can be inherited as an autosomal recessive, autosomal dominant, or X-linked recessive trait.  The hallmark symptoms are night blindness and gradually progressive peripheral visual field loss.

Retinitis Pigmentosa  The

most characteristic ophthalmoscopic findings are narrowing of the retinal arterioles, mottling of the retinal pigment epithelium, and peripheral retinal pigment clumping, referred to as “bone-spicule formation”.

Retinitis Pigmentosa  The

electroretinogram usually shows either markedly reduced or absent retinal function.  No effective therapy.

Diabetic retinopathy(RD) Diabetic patient  Damage of pericyte and endothelial cell of retinal capillary  One of the leading causes of blindness in the Western world  Two types: nonproliferative diabetic retinopathy proliferative diabetic retinopathy

Diabetic retinopathy(RD) 

Microvascular—the capillaries develop tiny dot-like outpouchings, while the retinal veins become dilated and tortuous (Back-ground diabetic retinopathy).

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Hemorrhages Macular edema—most frequent cause of visual loss among patients with background diabetic retinopathy.It caused primarily by a breakdown of the inner blood-retinal barrier at the level of the retinal capillary endothelium, allowing leakage of fluid and plasma constituents into the surrounding retina.

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Cotton-wool spot— microvascular occlusion (preproliferative diabetic retinopathy).

Diabetic retinopathy(RD) 

Neovascularization—new vessels bleed, massive vitreous hemorrhage may cause sudden visual loss.

Diabetic retinopathy(RD) treatment:   

Argon laser panretinal photocoagulation—indicated in proliferative RD Control the concentration of blood sugar Vitrectomy—RD, severe vitreous hemorrhage

Retinal artery occlusion: Pathogeny:   

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Narrow blood vessel and spasm vascular inflammation Operation of RD or intraorbital operation(sometimes) Arteriosclerosis

Retinal artery occlusion clinical finding:  Not

common but very serious prognosis  Two types: Central, branch

 History:  

Painless catastrophic visual loss occurring over a period of seconds for one eye Antecedent transient visual loss

 Examination: Visual acuity : between counting fingers and light perception (no light perception)  Light reflex of pupil: direct: ill eye—disappears indirect: ill eye—exists 

Retinal artery occlusion clinical finding:  Examination: Fundus: (Ophthalmoscopically) 1. The superficial retina becomes opacitied (The inner layer loses transparence to become grayishwhite edema due to ischemia). 2. Cherry-red spot: in the foveola Because the retina in macular area is thinner and without inner layer,so the edema is no obvious.The choroidal red background 3. BRAO: The retina in distributed area of the artery is in grayish(retina edema) 4. Retinal artery becomes narrow, with segmental fluxion of the blood

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Retinal artery occlusion clinical finding:    

FFA The filling time of retinal artery is prolonged The fluorecein is no filling in obstructed blood vessel or filling peak prolonged than the others A few cases: see doctor quite late In FFA, the sign of artery occlusion may not be seen,but the fundus change is very typical

Retinal artery occlusion clinical finding:   

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After few weeks: The function of the retina lost almost at all. The retina restores to transparency, but the ganglions and nerve fibers at occlusion area are dead. Optic atrophy and pale of the disk may be appeared in the trunk occlusion(CRAO) FFA: Artery blood flow had been restored to unobstructed, but the filling peak prolong than the other eye or other branch Some fundus are normal

Retinal artery occlusion Treatment: Retina ischemia is longer than 90 minutes: retina damage is irreversible (photoreceptor die) When diagnosis is clear: 4. Massage eyeball by himself at once: Close the eye--use the finger --press the eyeball for seconds--then loose finger for seconds--repeat. 5. Anterior chamber paracentesis (puncture) 6. Inhalation with mixed gas(95% oxygen+5%carbon dioxide),10 minutes every hour 7. Or inhalation of isoamyl nitrite 8. Retrobulbar injection: drugs:Tolazoline, papaverine(with the use of promote angiectasis ) 9. Treat systemic disorder: carotid and heart system(risk of cerebral infarction) 10. It must performed within 8 hours

Retinal vein occlusion:  Common

fundus disease

 Pathogeny: Extravascular compression: retina artery compress the neighbor vein at the arteriobenous crossing  Insufficient perfusion pressure or increased intraocular pressure or high blood viscosity. 1.Olds with hypertension and arteriosclerosis is commonly seen 2. Often complicated by insufficient blood erythrocytosis, glaucoma,diabetes,etc. 

Retinal vein occlusion clinical finding:  Two

types:BRVO is much common

than CRVO

 Clinical

finding Depend on the types  Easily diagnose  With potentially blinding complication  History:sudden painless loss of vision,often at about 0.1

Retinal vein occlusion clinical finding: Fundus Varies from a few small scattered retinal hemorrhages and cotton-wool sports to a marked hemorrhagic appearance with both deep and break through into vitreous cavity. Retinal vein –dilated tortuous with deep color Hemorrhages –flame-shape Optic disk—edema(severe cases) Yellowish-white hard lipid exudates—cystoid macular edema(CMD)with long ill course

Retinal vein occlusion FFA:  Ischemia:capillary occlusion in large area leading to extensive retinal ischemia

 Non-ischemia:prognosis is quite good   

Venous vascular walls—staining(In later stage of FFA) Retinal neovascularization—flourescein leakage Defilade

Retinal vein occlusion FFA:

Retinal vein occlusion treatment: *Isn’t specific therapy for RVO *Chinese traditional medicine *Careful follow-up evaluation is warranted *When develop anterior segment neovascularization, than prompt panretinal laser photocoagulation

Retinoblastoma(RB) 

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RB is a rare(morbidity rate is 1/15000-1/28000) but lifeendangering tumor of childhood.Two-thirds of cases appear before the end of third year. Bilateral disease occurs in 30% of cases. Generally a sign of heritable disease.An allele within chromosomal band 13q14(band 14 of long arm of chromosome) controls both the heritable and nonheritable forms of the tumor. The normal retinoblastoma gene is a suppressor gene or anti-oncogene. Gene defect or inactivation----tumor happen.

Retinoblastoma(RB) clinical findings: RB may exhibit outward or inward growth---either or both, gradually fill the eye and extend through the optic nerve to the brain. Less commonly, to the orbital tissue.  Occasionally, discharging malignant cells into vitreous or anterior chamber, producing a psedoinflammatory process. 

Early symptom isn’t obvious. RB usually remains unnoticed until it has advanced far enough to produce a white pupil (leukocoria). Simulate symptom: retrolental fibroplasia, persistence of the primary vitreous, retinal dysplasia, Coats’ disease, and nematode endophthalmitis.

Retinoblastoma(RB) clinical findings:   

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B-scan ultrasonic MRI X-ray: show calcific focus in the tumor CT

Retinoblastoma(RB) treatment: First of all, Rescue the baby’s life Then saved the eyeball  Laser photocoagulation or cryotherapy—small tumor,

localized at the retina, early stage, make the tumor necrosis and atrophy

 Radiotherapy

of sclera—60Co, 125I  Enucleation—over a quadrant, Operative manipulation should be gentle; cutting of the optic nerve should be as long as you can(should not less than 10mm)

 Evisceration

of orbit combined with radiotherapy or chemotherapy—extraocular stage, prognosis is quit worse

Retinoblastoma(RB) prevention:  

Not effective preventive High-risk family(got RB)—for every newborn baby should examine the fundus with mydriasis