Choroidal detachment is a detachment of the choroid from the underlying sclera due to the accumulation of fluid in the suprachoroidal space generally due to increased intraocular pressure (IOP), as observed in some settings:
- choroidal effusion
- transudative: trauma
- exudative: fluid accumulating in the suprachoroidal space secondary to many causes, most commonly inflammation (e.g. uveitis)
- choroidal hemorrhage: trauma and surgery
Please note that this article will prefer the term choroidal detachment regardless its fluid content, with choroidal effusion and choroidal hemorrhage used as its subtypes.
Depending or not on the rupture of small choroidal vessels, the content within the detachment may be hemorrhagic or effusion. Some of the more common causes of choroidal detachment are:
- spontaneous (Valsalva, etc.)
- medications for lowering IOP
- ocular hypotony: small globe with a characteristic umbrella sign or scleral infolding
- ocular neoplasms
- inflammatory choroidal disorders
- caroticocavernous fistula
- severe atherosclerosis
Imaging is usually not required unless a specific underlying cause, such as a metastasis is considered.
A high frequency, small footprint probe, performed through the closed eyelid provides excellent detail, typically demonstrating the following sonographic features :
- paired, convex echogenic bands extending posteriorly from the ciliary bodies
- remain fixed in position during eye movements, allowing differentiation from retinal and posterior vitreous detachments
- the detachment is not limited anteriorly by the ora serrata (compared to the retinal detachment that is limited)
- posteriorly the detachment diverges as it approaches the optic disc (compared to the retinal detachment that converges to the disc) due to the insertion of neurovascular structures at the ciliary body
- choroidal effusions appear on CT as hypodense linear fluid collections elevating a thick hyperdense choroid. On MRI, they usually will exhibit low T1 and high T2 signal
- choroidal hemorrhage classically appears as a hyperdense lentiform lesion on CT and, on MRI, will show hemoglobin products throughout the sequences, typically with a high T1 signal
Treatment and prognosis
In non-traumatic cases, the cause is treated and IOP is reduced with appropriate medication. Trauma cases may be treated with surgery, like non-traumatic cases persisting for a week or more, where the fluid may be drain and a tamponade method performed.
Un- or under-treated choroidal detachment can damage the cornea and cause cataracts.