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Dilated episcleral vessels refer to visibly enlarged veins on the surface of the white part of the eye (the episclera). They often indicate increased episcleral venous pressure or underlying vascular conditions, rather than simple irritation. These corkscrew-like vessels can appear in one or both eyes.
read more about dilated episcleral vessels ...The most common causes include elevated episcleral venous pressure from venous congestion or carotid-cavernous fistulas, systemic vascular disorders, thyroid disease, Sturge?Weber syndrome, or idiopathic causes. Inflammation of the sclera and episclera can also lead to vascular dilation. Surface irritation alone rarely produces this pattern.
The vessels appear as prominent red or corkscrew veins on the white of the eye. Depending on the underlying cause, people may also experience eye pressure, proptosis, or pulsatile noise. Vision is usually unaffected, but associated glaucoma may cause visual field loss.
Eye doctors examine the vessels with a slit lamp and measure intraocular pressure. They look for other signs such as blood in Schlemm canal, proptosis or bruit. Imaging studies like CT or MRI and angiography help identify underlying causes such as carotid-cavernous fistulas or venous obstruction. Systemic evaluation may be necessary.
Dilated episcleral vessels can be a sign of surface inflammation, eye pressure problems, or other conditions that need evaluation. An eye exam can check eye pressure and look for causes that are not obvious from appearance alone. If redness is paired with deep aching pain, light sensitivity, blurred vision, or nausea, seek urgent eye care. If the redness keeps returning in the same area, schedule a follow-up even if discomfort is mild.
They are usually a sign of another problem rather than a disease themselves. Prompt evaluation is important to rule out sight-threatening causes, but the vessels alone do not damage vision.
Vision is typically unaffected unless the underlying condition raises eye pressure enough to damage the optic nerve.
Surface rubbing or dryness may make veins temporarily more visible but does not cause persistent dilation. Persistent dilation usually indicates systemic or ocular vascular problems.
Seek care promptly if you notice persistent dilated vessels, especially if accompanied by pain, double vision, proptosis, or vision changes. Early diagnosis helps guide proper treatment.
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Carotid Cavernous Fistula Ophthalmological Implications. National Library of Medicine (PMC). https://pmc.ncbi.nlm.nih.gov/articles/PMC2813585/. Published 2009
Elevated Episcleral Venous Pressure (EVP). American Academy of Ophthalmology EyeWiki. https://eyewiki.org/Elevated_Episcleral_Venous_Pressure_%28EVP%29. Published on April 29, 2025
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