Retinal vascular occlusions

1
Retinal vascular occlusions

• Retinal venous and arterial occlusions are among
  the more common serious ophthalmic conditions
  presenting acutely.
• Should be always considered in the DDx of a pt
  with sudden painless loss of vision.
• Usually a manifestation of a systemic disease.

2
Venous occlusion

• Pathogenesis
• Central retinal vein occlusion (CRVO) may result
  from
• 1- Abnormality of the blood itself (the
  hyperviscosity syndromes and abnormalities in
  coagulation).
• 2- An abnormality of the venous wall
  (inflammation).
• 3- An increased ocular pressure.

3

• History
• The patient complains of a sudden partial or
  complete loss of vision although onset may be
  less acute than that of arterial occlusion.
• This loss of vision occurs when the involved
  segment of retina includes the macula
• Variability of the initial fall in visual
  acuity- ranging from 6/9 to hand movm.
• Signs
• These contrast markedly with those of arterial
  occlusion.
• There is marked haemorrhage and great tortuosity
  and swelling of the veins.
• The optic disc appears swollen.
• Macular edema may be seen.

4

• Signs cont.
• Branch retinal vein occlusion may originate at
  the crossing point of an arteriole and a vein
  where the arteriole has been affected by
  arteriosclerosis associated with hypertension
  (a/v nipping) ? Subsequently
• 1- Abnormal new vessels may grow on the
  retina and optic disc, causing vitreous
  haemorrhage. This happens if the retina has
  become ischaemic as a result of the vein
  occlusion (an ischaemic retinal vein occlusion).
• 2- In ischaemic retinal vein occlusion
  abnormal new vessels may grow on the
  iris(rubeosis) causing rubeotic glaucoma.

5

• Investigation
• Vascular and haematological work-up to exclude
  increased blood viscosity.
• CRVO is also associated with raised ocular
  pressure, diabetes and hypertension.
• Treatment
• Retinal laser treatment is given if the retina is
  ischaemic to prevent the development of retinal
  and iris new vessels.
• Laser treatment may improve vision in some
  patients with a branch retinal vein occlusion by
  reducing macular oedema.

6

• Prognosis
• The vision is usually severely affected in
  central, and often in branch vein occlusion and
  usually does not improve.
• Younger patients may fare better, and there may
  will be some visual improvement.