Retinal Vein Occlusions:
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Introduction
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Retinal vein occlusions are a common cause of visual loss in the West, and are the second commonest cause of reduced vision due to retinal vascular disease after diabetic retinopathy
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It is of 2 types - BRVO (Branched Retinal Vein Occlusion (BRVO) and CRVO (Central Retinal Vein Occlusion)
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BRVO is more frequent than CRVO.
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Risk Factors :​
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RVO frequency increases with increasing age.
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Commonly associated systemic diseases are :
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Hypertension
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Diabetes Mellitus
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Hyperlipidaemia
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Hyperhomocysteinaemia (especially in patients less than 40 years of age)
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Blood coagulation disorders (especially in patients less than 40 years of age) )
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Clinical Presentation & Treatment:
The clinical presentations are related to the primary effects related to the vein occlusion :
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Macular edema- Fluid collects in the areas of retina responsible for central vision called the macula. The fluid causes swelling or edema of the macula, causing a person’s central vision to become blurry. This condition is called macular edema.
It causes sudden, painless decrease in vision in one eye that can become worse over several hours or days
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Image 1 :Retina shows presence of multiple hemorrhages throughout the retina with or without disc edema (black arrow in the fundus photo)
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Image 2 : OCT (Retina scan) shows presence of Macular edema – Retina swelling – shown by white arrow
Prompt treatment in the form of intravitreal injections – injections in the eye are required to recover the blurred vision
Timely management can prevent blindness due to RVO
2. Tractional retinal detachment and Neovascular glaucoma – neglected and undiagnosed cases have about 10% chance of developing these VEGF related complications.
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Tractional retinal detachment - Typically patients present with sudden, painless loss of vision. The patient was seeing well for few days prior to this event when he had sudden loss of vision.
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The treatment at this point is vitreous surgery in the form of vitrectomy and endolaser. Silicone oil requirement would depend on the status of retina on table.
Retina shows presence of sclerosed blood vessels along with new vessels(red) and tractional retinal detachment (white arrow) at edge of macula. Peripheral and posterior sectoral laser could successfully prevent vision loss in this patient
Neovascular glaucoma – Patient presents with sudden painful red eye with loss of vision.
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It is a medical emergency and the response time in consulting a doctor and treatment would eventually determine the outcome in terms of vision improvement.
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In later stages, cryotherapy and enucleation especially in cases of painful blind eye are the last resort to treatment
Presence of red blood vessels on the iris is an indicator of noevascularisationof the iris – an indicator of start of neovascular glaucoma