Retinal vascular diseases 2 Dr. Mohammad Shehadeh

Retinal vein occlusion Classification: Branch retinal vein occlusion Central retinal vein occlusion

Pathogenesis Atherosclerosis of the retinal arterioles make them rigid and they compress the veins when they cross it causing it to thrombose  causing branch retinal vein occlusion Central retinal vein and artery share a common adventitial sheath posterior to lamina cribrosa, so that atherosclerosis changes of the artery may compress the vein causing its thrombosis  and cause central retinal vein occlusion

Risk factors of retinal vein occlusion Old age : 50% over the age of 65 Systemic conditions: Hypertention, hyperlipidemia, diabetes, smoking and obesity. Raised intraocular pressure Inflammatory diseases such as sarcoidosis Thrombophilic disorders : inherited or aquired

Branch retinal vein occlusion Presentation: depend on the extent of macular involvement. If the macula not involved it may be asymptomatic Sudden onset of blurred vision Metamorphopsia Relative visual field defect

signs Visual acuity: depend on the extent of macular involvement Fundus signs: Venous dilatation and tortuousity Flame shaped hemorrhages Retinal edema Cotton wool spots

FA : eary hypofluorescence due to blockage by edema and blood and late hyperfluorescence due to leakage of dye Prognosis: reasonably good 50% return to visual acuity of 6/12 or better within 6 mounths Vision threatenin complications of BRVO: 1- chronic macular edema 2- neovascularization: NVD or NVE

Management of BRVO We review the patient every 6-12 weeks When the hemorrhages resolve we do FA: FA shows good macular perfusion and vision is good no treatment is required FA shows macular edema with good macular perfusion and vision is 6/12 or worse after 3 months  laser photocoagulation should be considered but if vision is better than 6/12  no treatment is needed FA shows macular non perfusion and visual acuity is poor  laser treatment will not improve vision. FA shows 5 or more disc diameters of non perfusion the patient should be reviewed every 4 months for 1-2 years because there is risk of neovascularization

Central retinal vein occlusion Non-ischemic CRVO : 75% of cases Ischemic CRVO

Non-ischemic CRVO Clinical features: Presentation: with sudden blurred vision Visual impairment : moderate to severe Afferent pupillary defect (APD): abscent or mild

Fundus features: Tortuousity and dilatation of all branches of central retinal vein Retinal dot-blot and flame shaped hemorrhages all over the four retinal quadrant Occasional cotton wool spots Mild to moderate optic disc edema and macular edema

FA : shows Delayed venous return Good retinal capillary perfusion Late leakage Course: Most signs resolve over 6-12 months Conversion to ischemic type can occur in 34% within 3 years

Prognosis: In cases that do not convert to ischemic type, prognosis is good, with return of visual acuity to normal or near normal in about 50% Management: Follow up should be for years to detect conversion to ischemic CRVO High intensity laser to create anastomosis between retinal vein and choroidal vein, but it may cause fibrosis at the laser site or hemorrhage from ruptured vein

Ischemic central retinal vein occlusion Clinical features: Presentation: sudden and severe visual impairment Visual impairent: severe APD : severe

Fundus features: Marked tortuousity and engorgement of all branches of central retinal vein Extensive dot-blot and flame shaped hemorrhages Cotton wool spots which may be numerous Macular edema Severe optic disc edema

FA: central masking by retinal hemorrhages and extensive areas of capillary non-perfusion Course: most acute signs resolve over the next 9-12 months Prognosis: extremely poor due to macular ischemia, rubeosis iridis develop in about 50% of cases usually 2-4 months and there is high risk of neovascular glaucoma

Management: Follow up monthly for 6 months in order to detect rubeosis iridis and with gonioscopy to detect angle neovascularization If neovascularization develops , laser PRP should be done without delay

Retinal artery occlusion Branch retinal artery occlusion (BRAO) Central retinal artery occlusion (CRAO) Cilioretinal artery occlusion

Causes: Atherosclerosis-related thrombosis(most common cause of CRAO) 80% of cases Carotid embolism Giant cell arteritis Cardiac embolism Priarteritis in cases of systemic vasculitis, such as SLE , Behcet…Etc. Thrombophilic disorders such as antiphospholipid syndrome

Branch retinal artery occlusion BRAO is most frequently caused by embolism Presentation: with sudden and profound sectoral visual field loss Fundus features: retinal cloudining corresponding to the area of occluded artery narrowing and segmentation of blood column One or more emboli may be present

FA: Delay in arterial filling Masking of background fluorescence by retinal swelling which is confined to the involved sector Prognosis : Poor unless the obstruction can be relieved within few hours

Central retinal artery occlusion CRAO is most frequently the result of atherosclerosis Presentation: sudden and profound loss of vision except when a portion of the papillomacular bundle is supplied by cilioretinal artery, when central vision is preserved APD is profound or total

Fundus features: Attenuation of arteries and veins with segmentation of the blood column Extensive retinal cloudiness Cherry red spot : which is an red-orange reflex from intact choroid appearing through the thin fovea In eyes with cilioretinal artery , part of the macula will appear normal in colour

FA: Shows delay in arterial filling Masking of background choroidal fluorescence by retinal swelling A patent cilioretinal artery will fill during the early phase Prognosis: Is poor due to retinal infarction Rubeosis iridis may occur and need PRP laser

Cilioretinal artery occlusion Cilioretinal artery present in 20% of population It arises from posterior ciliary circulation but supplies the retina, in the area of the macula and papillomacular bundle

Classification: Isolated: typically affects young patients with an associated systemic vasculitis Combined with CRVO: has similar prognosis to non-ischemic CRVO Combined with anterior ischemic optic neuropathy: affects patients with giant cell arteritis and carry a very poor prognosis

Presentation: with acute, severe loss of central vision Fundus: cloudiness localized to that part of the retina normally perfused by the vessel FA: shows corresponding filling defect

Treatment of acute retinal artery occlusion Initial treatment: Ocular massage: by 3 mirror contact lens, press for 10 seconds then release for 5 seconds. Sublingual isosorbide dinitrite: to dilate perepheral blood vessles and decrease resistance Lowering of IOP with intravenous acetazolamide and mannitol

Subsequent treatment If the above mentioned measures are unsuccessful after 20 minutes we can do the following: Anterior chamber paracentesis IV streptokinase ( thrombolytic drug ) Retrobulbar injection of tolazoline to decrease retrobulbar resistance to flow

Hypertensive retinopathy Hypertension is diagnosed on blood pressure reading on several consecutive occasions 140/90 or over.

Retinal changes: Arterial narrowing : May be focal or generalized Severe hypertention may lead to obstruction of precapillary arterioles and the development of cotton wool spots Vascular leakage: Leading to flame shaped retinal hemorrhages , retinal edema , hard exudates and macular star. Swelling of the optic disc is the hallmark of malignant hypertension.

Arteriosclerrosis: Involves thickenning of the vessel wall The most important sign is arteriovenous nipping Grades of arteriosclerosis: Grade 1 : subtle broadening of arteriolar light reflex Grade 2 : bending of veins at arteriovenous crossings Grade 3 : copper wiring Grade 4 : silver wiring

Choroidal changes: Rare and developes in acute hypertensive crisis Elshing spots: focal choroidal infarcts Siegrist streaks: fibrinoid necrosis Exudative retinal detachment: associated with toxemia of pregnancy.

Retinopathy of prematurity (ROP) It is aproliferative retinopathy affecting pre-term infants of low birth weight who have been exposed to high ambient oxygen concentration The vessles reach the nasal periphery after 8th month of gestation but do not reach the temporal perephery until 1 month after delivery The incompletely vascularized temporal retina is particularly susceptible to oxygen damage especially in preterm infants

Active ROP Severity: determined in terms of (a)location (b)extent (c) stages (d) plus disease (a) Location : It is determined by three zones centered on the optic disc

(b) Extent: determined by the number of clock hours of the retina involved (c) Staging : Stage1: demarcation line Stage 2: ridge Stage 3: ridge with extraretinal fibrovascular proliferation Stage 4: subtotal retinal detachment Stage 5: total retinal detachment

Oher considerations Plus disease: signifies tendency to progression. Characterized by: 1- failure of pupil to dilate 2- development of vitreous haze 3- dilatated tortuous vessles 4- Preretinal and vitreous hemorrhage

Threshold disease It is the indication of treatment in ROP. It is the presence of five consequetive hours or 8 non-consequetive hours of stage 3 in zone 1 or 2 associated with plus disease

screening Babies born at or before 31 weeks or weighing 1500g or less should be screened for ROP When to screen? At the gestational age 34 or 4 weeks post delivery which ever comes later.

Treatment: Ablation of immature retina by cryotherapy or laser ( successful in 85% of cases only) Retinal surgery in cases of retinal detachment