1. Retinal vascular diseases 2
Dr. Mohammad Shehadeh

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

3. 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

4. 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

5. 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

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

8. 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

9. 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

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

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

13. 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

15. 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

16. 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

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

18. 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

20. 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

21. 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

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

23. 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

24. 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

26. 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

27. 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

28. 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

30. 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

31. 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

32. 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

34. 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

35. 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

36. 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

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

38. 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.

39. 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

41. 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.

43. 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

44. 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

45. (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

47. 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

48. 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

49. 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.

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