Sudden loss of vision is an ophthalmological emergency and requires immediate referral to the eye emergency department.
- mild cases usually do not require any treatment. Frequently they are young people. Visual acuity is 6/24 or better and peripheral vision is relatively normal. The retinal haemorrhages gradually absorb over 2-3 months and collaterals frequently develop around the optic disc to restore normal blood flow. Normal vision is often restored although patients in whom the fovea was damaged by oedema may have a persistent central scotoma
- older patients tend to be more severely affected with acuity reduced to 6/60 or worse. Peripheral vision is often reduced. The retinal haemorrhages absorb slowly and the fovea may be left chronically oedematous. The vitreous may be severely liquefied removing the diffusion barrier to angiogenesis stimuli from the retina. Neovascularisation occurs on the surface of the iris and the anterior chamber angle resulting in peripheral anterior synechiae and secondary glaucoma. Photocoagulation may be preventive.
Dexamethasone intravitreal implant is recommended as an option for the treatment of macular oedema following central retinal vein occlusion (1).
Ranibizumab is recommended as an option for treating visual impairment caused by macular oedema following central retinal vein occlusion (2).
Aflibercept (a vascular endothelial growth factor (VEGF) inhibitor) solution for injection is recommended as an option for treating visual impairment caused by macular oedema secondary to central retinal vein (3)
Notes:
- ranibizumab belongs to a class of drugs that block the action of vascular endothelial growth factor (VEGF)-A
- retinal vein occlusion (RVO) is a common cause of reduced vision as a result of retinal vascular disease. Thrombosis in the retinal veins causes an increase in retinal capillary pressure, resulting in increased capillary permeability and the discharge of blood and plasma into the retina. This leads to macular oedema and varying levels of ischaemia through reduced perfusion of capillaries. These changes trigger an increase in VEGF, which increases vascular permeability and new vessel proliferation
- by inhibiting the action of VEGF-A, ranibizumab reduces oedema and limits visual loss or improves vision.
Reference: