VASCULAR DISORDERS OF RETINA

BY:

HARIS KHANROLL # 100

ANATOMY OF RETINA

The retina is a thin, semitransparent, multilayered sheet of neural tissue that lines the inner aspect of the posterior

two-thirds of the wall of the globe.

LANDMARKS OF RETINA1. Optic Disc2. Retinal Blood

Vessels3. Area centralis with

fovea and foveola4. Peripheral retina

and ora serrata5. Thickest near the

optic disc6. Thin towards the

peripheral

MICROSCOPIC STRUCTURE

BLOOD SUPPLY OF THE RETINA:•Outer 4 layers of retina is supplied by (till outer nuclear layer) choriocapillaries.•The inner six layers gets its supply from central retinal artery which is a branch of ophthalmic artery.•The outer plexiform layer gets partly by both the above arteries.•The fovea is avascular and is mainly supplied by choriocapillaries.•The inner portion of the retina is perfused by branches of the central retinal artery.•In 30% of eyes ,a cilioretinal artery,branching from the ciliary circulation ,supplies part of inner retina mainly The Macula Region.•The retinal blood vessels maintain the inner blood-retinal barrier.This physiological barrier is due to single layer of non-fenestrated endothelial cells,whose tight junctions are impervious to tracer substances such as fluorescein.

•Retinal blood vessels lack an internal elastic lamina & a continuous layer of smooth muscle cells.•The retinal arteries are end arteries & have no anastomoses.The only place where the retinal system anastomoses is in the neighbourhood of lamina cribrosa.•The veins of the retina unite to form Central retinal vein at the disc, which follows the corresponding artery.•The terminal fundus arterioles bend sharply and dip almost vertically into the retina.•In most of the Extramacular fundus- two retianal capillary networks- a superficial and a deep.•In parafoveal zone it is well developed and in 3 layers.•A capillary free zone of 500miceo metre diameter in foveal zone- FAZ.

VASCULAR DISORDERS OF RETINA

1. DIABETIC RETINOPATHY2. HYPERTENSIVE RETINOPATHY

3. RETINAL VEIN OCCLUSION4. RETINAL ARTERY OCCLUSION

5. RETINOPATHY OF PREMATURITY

DIABETIC RETINOPATHY• Diabetic retinopathy is a disorder of the retinal

vessels that eventually develops to some degree in nearly all patients with long-standing

diabetes mellitus. • Most Common cause of bilateral severe visual

loss in working age group in US

RISK FACTORS• Age at diagnosis of diabetes• Duration• Poor control of diabetes• Pregnancy• Hypertension• Nephropathy• Hyperlipidemia• Obesity• Anemia• Smoking• Cataract surgery

PATHOGENESISMICROVASCULAR LEAKAGE1. LOSS OF PERICYTES2. MICRO ANEURYSM3. BLOOD RETINAL BARRIER

BREAKDOWN

IT CAUSES4. RETINAL OEDEMA5. HARD EXUDATE6. RETINAL HEMORRHAGES

• SUPERFICIAL(FLAME SHAPED)

• DEEP(DOT AND BLOT)

MICROVASCULAR OCCLUSION1. THICKENING OF BASEMENT

MEMBRANE2. ENDOTHELIAL DAMAGE3. STICKNESS AND AGGREGATION OF

PLATELETS4. FIBRINOLYTIC SYSTEM IS DEFECTIVE5. RED CELL AGGREGATION6. DEFECTIVE OXYGEN TRANSPORT

IT CAUSES7. RETINAL ISCAEMIA(COTTON WOOL

SPOTS)8. NEOVASCULARIZATION ON THE

SURFACE OF RETINA,OPTIC NERVE HEAD AND IRIS(RUBEOSIS IRIDIS)

9. ARTERIO VENOUS SHUNTS

SIGNS1. BACKGROUND DIABETIC RETINOPATHY2. PREPROLIFERATIVE STAGE3. PROLIFERATIVE STAGE4. DIABETIC MACULOPATHY5. ADVANCED STAGE

BACKGROUND DIABETIC RETINOPATHY

1. MICROANEURYSMS

MICRO ANEURYSMS

2. HAEMORRHAGES

1. FLAMED SHAPED HAEMORRHAGES

2. DOT AND BLOT HAEMORRAGES

3. HARD EXUDATES• LOCATED

BETWEEN INNER PLEXIFORM AND INNER LAYER OF RETIINA

• COMPOSED OF PLASMA PROTEINS AND LIPID

• YELLOW WAXY APPEARANCE WITH DISTINCT MARGINS

4. RETINAL EDEMAIT CAUSES THICKENING OF RETINA AND GIVES CYSTOID APPEARANCE TO RETINA

PREPROLIFERATIVE CHANGES

1. VASCULAR CHANGES• VENOUS CHANGES IN THE FORM OF

BEADING,LOOPING AND SAUSAGE LIKE SEGMENTATION

• ARTERIOLES BECOME NARROW

Retinal arteriole obliterationVenous Segmentation

Venous BeadingVenous Loop

2. COTTON WOOL SPOTS

APPEAR AS WHITISH,GREY AREAS WITH INDISTINCT MARGINS

3.DARK BLOT HAEMORRHAGETHEY REPRESENT HAEMORRHAGIC RETINAL INFARCTS

INTRA RETINAL MICROVASCULAR ABNORMALITIES

PROLIFERATIVE DIABETIC RETINOPATHY NEO

VASCULARIZATION : DISC

NEW VESSELS GROW OR

PROLIFERATE ON THE OPTIC NERVE

HEAD

2. NEO VASCULARIZATION

ELSEWHERE:NEW VESSELS PROLIFERATE

ALONG COURSE OF INTERNAL

TEMPORAL VASCULAR

ARCADES OR OTHER AREAS OF

RETINA

ADVANCED DIABETIC EYE DISEASE

• Pre retinal hemorrhage

• Vitreous hemorrhage

• Traction RD• Rubeosis

Iridis• Neovascular

Glaucoma

DIABETIC MACULOPATHYCAUSES1. OEDEMA2. HARD EXUDATE3. MACULAR

HAEMORRHAGE4. MACULAR ISCHAEMIA5. PRE MACULAR

MEMBRANE FORMATION

6. MACULAR TRACTION OR DETACHMENT

CLINICAL TYPES1. FOCAL EXUDATIVE2. DIFFUSED EXUDATIVE3. ISCHAEMIC4. MIXED MACULOPATHY

DIAGNOSIS1. FUNDUS EXAMINATION WITH

• DIRECT OPHTHALMOSCOPE• INDIRECT OPHTHALMOSCOPE

• SLIT LAMP BIMICROSCOPY WITH CONTACT LENS AND NON CONTACT LENS

2. FUNDUS FLUORESCEIN ANGIOGRAPHY FOR ASSESSMENT OF:

• LEAKING AREAS• OCCLUSION AREAS

3. OPTICAL COHERENCE TOMOGRAPHY IS USEFUL TO ASSESS RETINAL OEDEMA

TREATMENTMEDICAL1. CONTROL OF RISK FACTORS

• DIABETES MELLITUS• HYPERTENSION,ANAEMIS,NEPHROPATHY,HYPERLIPI

DEMIA2. ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR3. INTRAVITREAL STEROIDS ARE USEFUL TO REDUCE THE MACULAR OEDEMA (INTRAVITREAL INJECTION OF TRIAMCINOLONE)

LASER PHOTOCOAGULATIONOBJECTIVES1. TO DESTROY THE HYPOXIC

RETINA ,STOP THE RELEASE OF VASOFORMATIVE SUBSTANCE AND CAUSE INVOLUTION OF NEW VESSEL

2. TO DESTROY THE LEAKAGE AREAS AND ENHANCE THE ABSORPTION OF OEDEMA AND EXUDATE

TYPES1. FOCAL TREATMENT

FOR FOCAL MACULAR OEDEMA

2. GIRD TREATMENT FOR DIFFUSE MACULAR OEDEMA

3. PANRETINAL PHOTOCOAGULATION

SURGERYPARS PLANA VITRECTOMY IS INDICATED FOR:1. DENSE PERSISTENT

VITREOUS HAEMORRHAGE2. TRACTIONAL RETINAL

DETACHMENT3. EPIRETINAL MEMBRANES

HYPERTENSIVE RETINOPATHYDEFINITION

HYPERTENSIVE RETINOPATHY IS A RETINAL VASCULAR DAMAGE CAUSED BY

HYPERTENSION.

Pathophysiology

Systermic chronic hypertension

Arteriosclerosis and

atherosclerosis predominates

Narrowing of retinal arterioles Retinal Ischaemia

HypoxiaIncreased capillary

permeability

Focal Retinal Oedema, retinal

haemorrhage,cotton wool spots, hard exudates

1.

1. The cardinal funduscopic feature of malignant hypertension is disk swelling, which appears as blurring and elevation of disk margins. The top image also shows a characteristic star-shaped macular lesion caused by leaking retinal vessels; the bottom image also shows a characteristic

flame-shaped hemorrhage and dilated veins.2. Moderate hypertensive retinopathy is characterized by thinned, straight arteries; intraretinal

hemorrhages; and yellow hard exudates (top). Cotton-wool spots (bottom) are an additional feature of moderate hypertensive retinopathy. They are caused by focal axonal swelling of the

retinal nerve fiber layer as a result of small-vessel occlusion.

Retinal arteriolar narrowing due to thickening and opacification of arteriolar walls (copper wiring) caused by hypertensive arteriosclerosis. Image also

shows macular edema.

Classification• Keith-Wagener-Barker classification

Grade DescriptionGrade 1 Slight narrowing, sclerosis, and tortuosity of the retinal arterioles; mild,

asymptomatic hypertensionGrade 2 Definite narrowing, focal constriction, sclerosis, and AV nicking; blood

pressure is higher and sustained; few, if any, symptoms referable to blood pressure

Grade 3 Retinopathy (cotton-wool patches, arteriolosclerosis, hemorrhages); blood pressure is higher and more sustained; headaches, vertigo, and nervousness; mild impairment of cardiac, cerebral, and renal function

Grade 4 Neuroretinal edema, including papilledema; Siegrist streaks, Elschnig spots; blood pressure persistently elevated; headaches, asthenia, loss of weight,

dyspnea, and visual disturbances; impairment of cardiac, cerebral, and renal function

Modified Scheie classification

Grade 0 - No changes

Grade 1 - Barely detectable arterial narrowing

Grade 2 - Obvious arterial narrowing with focal irregularities

Grade 3 - Grade 2 plus retinal hemorrhages and/or exudates

Grade 4 - Grade 3 plus disc swelling

Retinal Vein Occlusion• Definition:

o It is a common vascular disorder characterized by retinal vein occlusion resulting in edema and hemorrhages on retina in the affected region with potential blinding complications

• Types:o Central retinal vein occlusiono Branch Retinal vein occlusion

• Etiology and Risk Factors:o Age of age of above 50 yearso Systemic diseases like hyperlipidemia, Diabetes, Chronic

Renal Failureo Chronic Open Angle Glaucoma

Retinal Vein Occlusion• Clinical Presentation:

o Sudden painless loss of visiono Persistent decreased central vision

• Clinical Examination:o Visual Acuity- Severe visual loss, up to 20/200o Intra Ocular Pressure- Raisedo Fundus Examination- dilated, tortuous veins, retinal and

macular edema, flame shaped hemorrhages, and cotton wool spots

Central retinal vein occlusion Clinical manifestation• Non-ischemic type

– Mild fundus change : retinal hemorrhage and tortuous vein– Mild VA decrease– capillary nonperfusion rare– Visual field defect (retinal hemorrhage)

• Ischemic type ：– More common– Extensive retinal

hemorrhage and tortuous vein ， Multiple cotton-wool spots

– Severe VA decrease

– Widespread capillary nonperfusion ， 60% cases present iridal neovascularization.

BRANCH RETINAL VEIN OCCLUSION• MORE COMMON THAN

CRVO• OEDEMA AND

HAEMORRHAGE LIMITED TO THE AFFECTED VEIN

• VISSION AFFECTED ONLY MACULAR AREA IS INVOLVED

• SECONDARY GLAUCOMA OCCURS RARELY

• PROGNOSIS IS REASONABLY GOOD

Retinal Vein Occlusion• Investigations:

o Fluorescein Angiographyo ECGo Blood CPo ESRo Blood Glucose level

• Complications:o Chronic Macular Edemao Conversion from Non-Ischemic to Ischemic typeo Retinal Neovascularizationo Neovascular Glaucoma

Retinal Vein Occlusion• Treatment:

o Macular Laser Photocoagulationo Intra Vitreal injections anti-VEGF and steroidso Intra Vitreal triamcinolone injections

Retinal Artery Occlusion

• Definition:o Vascular disorder of retina resulting in sudden painless

loss of vision, with antecedent transient visual loss• Types:

o Central Retinal Artery Occlusiono Branch Retinal Artery Occlusion

• Etiology:o Thrombosis due to atherosclerosiso Embolismo Raised Intra Ocular Pressureo Giant Cell Arteritiso Angiospasm- Retinal Migraine

Clinical manifestation

Symptoms

Signs

Sudden painless vision lose of one eye

Direct light reflex disappear, indirect light reflex normal

Retinal edema、 cherry-red spotRetina artery narrow，mild hemorrhage

CENTRAL RETINAL ARTERY

OCCLUSION• RETINAL OEDEMA

• CHERRY RED SPOTS• RETINAL ARTERY

NARROW • MILD

HAEMORRHAGE• WHITISH

APPEARANCE OF RETINA

BRANCH RETINAL ARTERY

OCCLUSION• DUE TO LODGMENT OF

EMBOLI AT BIFURCATION OF RETINAL ARTERY

• RETINAL DISTAL TO OCCLUSION BECOMES OEDEMATIOUS WITH

NARROWED ARTERIOLES• INVOLVED AREA ATROPHIED CAUSING

SECTORIAL VISUAL FIELD DEFFECT PERMANANTLY.

Retinal Artery Occlusion

• Treatment:o Intraocular pressure lowered immediately by anterior

chamber paracentasis or I.V Acetazolamideo Inhaled oxygen and carbon dioxide mixture to improve

oxygen delivery to retinao Thrombolytic therapy

Retinopathy Of Prematurity

• Definition:o It is a bilateral vasoproliferative retinopathy occurring in

premature infants with low birth weight and exposed to high concentration of oxygen

• Etiology and Risk Factors:o Low birth weighto Exposure to high concentrations of oxygeno Premature birth

• Pathology:o THE TEMPORAL RETINAL VASCULARIZATION IS

COMPLETED 1 MONTH AFTER BIRTHo TOXIC LEVEL OF OXYGEN INTERFERES WITH

REVASCULARIZATION BY DAMAGING THE ENDOTHELIUM AND OBLITERATING NEWLY FORMED CAPILLARIES.

Retinopathy Of Prematurity

Stage 1- Changes at junction of vascular and avascular retina as demarcation line

Retinopathy Of Prematurity

Stage 2- Formation of distinct ridge

Retinopathy Of Prematurity

Stage 3- Extra retinal fibrovascular proliferation

Retinopathy Of Prematurity

Stage 4- Severe retinal detachment

Retinopathy Of Prematurity

Stage 5- Total retinal detachment seen as whitish mass (leukocoria) behind iris

Retinopathy Of Prematurity

• Treatment:o Peripheral retinal laser in stage 2o Ablation of avascular retina in stage 3o Vitreotomy in stage 4 & 5