Managing Choroidal Effusions after Glaucoma Filtration Surgery

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Disease Entity

A choroidal detachment is defined by the abnormal presence of fluid in the suprachoroidal space, which is the potential space between the choroid and the sclera. It may occur in two types—serous and hemorrhagic. Serous choroidal detachments, also known as choroidal effusions, are a frequent complication of glaucoma surgery.


  • H31.4 Choroidal detachment.
  • H31.8 Other specified disorders of choroid
  • H59.8 Other intraoperative and postprocedural complications and disorders of eye and adnexa, not elsewhere classified


Choroidal effusion

The most common cause of choroidal effusions is glaucoma surgery. Glaucoma filtering procedures may result in hypotony, particularly in the setting of over-filtration or a bleb leak. When hypotony occurs after glaucoma surgery, it results in pressure-driven osmotic shifts of serous fluid into the suprachoroidal space. Inflammation may also contribute by causing decreased vascular permeability. Once choroidal effusions develop, they may further exacerbate hypotony by reducing aqueous humor production.

In addition to glaucoma surgeries, choroidal effusions may also be caused by other intraocular surgeries. Further, they may result from trauma, inflammatory conditions, infectious processes, neoplasms, drug reactions, and disease states resulting in venous congestion.

The terms choroidal effusion, ciliochoroidal effusion, choroidal detachment, and ciliochoroidal detachment describe similar entities and are sometimes used interchangeably in the literature. However, choroidal detachment is a broader term than choroidal effusion. Choroidal detachments may be serous or hemorrhagic. The terms choroidal effusion, ciliochoroidal effusion, and serous choroidal detachment describe the same entity.



Relatively common after glaucoma filtration surgery, particularly in the setting of post-operative hypotony. However, choroidal effusion often goes undetected and/or unreported.


No mortality has been reported.

Cyclitic pupillary membranes may develop. When a flat chamber is present, corneal endothelial damage and peripheral anterior synechiae can occur.

Chronic choroidal detachment can lead to hypotony maculopathy and globe phthisis.

In hemorrhagic choroidal detachment, morbidity is the same as for serous detachment, but the prognosis is worse.

Loss of useful vision is reported in up to 40% of cases.


No racial predilection exists.


No sexual predilection exists.


Hemorrhagic traumatic detachments are seen more frequently in elderly patients.


  • Postoperative hypotony is the most common causative factor. This most frequently occurs after glaucoma surgery, but can also occur in the setting of other intraocular surgeries.
  • Other causative factors include ocular trauma, infection, inflammation, malignancy, or venous congestion. The use of some medications has also reportedly been associated with serous choroidal detachments.
  • Idiopathic causes fall under the umbrella of uveal effusion syndrome, a rare condition considered a diagnosis of exclusion.
  • Hemorrhage occurs when choroidal vessels rupture. Hemorrhagic choroidal effusions often occur in the setting of globe trauma. Additionally, they are more likely in patients with systemic hypertension, intraoperative tachycardia, or arteriosclerosis.
  • Sudden globe decompression during surgery predisposes to choroidal detachment, particularly if the eye is affected by glaucoma and surgery is initiated when the IOP is still elevated.

Risk Factors

  • Ocular medications:
    • The use of antimetabolites such as mitomycin C (MMC) during trabeculectomy surgery is a significant risk factor for clinically significant choroidal effusions. These typically develop in the setting of prolonged hypotony.
    • The use of aqueous suppressants after trabeculectomy or glaucoma drainage device implantation may place patients at increased risk for developing hypotony and choroidal effusions postoperatively.  Late choroidal effusions may develop with latanoprost use after cataract extraction.
  • Systemic medications: Warfarin, sulfonamides, tetracyclines, diuretics, and selective serotonin reuptake inhibitors.
  • Iridotomy
  • Pre-existing conditions: Nanophthalmos and Sturge-Weber syndrome.
  • Eye trauma
  • Older age
  • Atherosclerosis
  • History of choroidal detachment in the other eye


In a normal eye, the suprachoroidal space is essentially nonexistent because of close apposition of the choroid to the sclera. In pathologic conditions that disrupt the normal ocular fluid dynamics and hydrostatic and oncotic pressure gradients, fluid accumulates in this potential space.

Serous choroidal effusions involve transudation of serum into the suprachoroidal space, whereas hemorrhagic choroidal effusions involve blood accumulation from rupture of choroidal vessels. Choroidal effusions represent tissue edema and are best understood through Starling’s law, which elucidates the balance of hydrostatic and osmotic gradients between the choroidal capillaries and interstitial space of the eye.

With this approach, the intraocular pressure (IOP) can be thought of as the hydrostatic pressure in the interstitial space. Thus, any process that shifts flow from the choroidal capillaries into the interstitium may lead to an effusion. A decrease in IOP allows fluid to accumulate in the interstitial spaces, while inflammation increases the permeability of the choroidal capillaries.

These mechanisms suggest that choroidal effusions form either as a result of increased transudation through the choroidal capillary walls or from a drop in IOP caused by an increase in uveoscleral outflow of aqueous humor.

Primary Prevention

The best strategy for handling acute intraoperative choroidal effusions is to prevent them by minimizing hypotony and inflammation intra-operatively and post-operatively.

Pre-operative care: Pre-operative osmotics or carbonic anhydrase inhibitors can be used to decrease the IOP to a safe level before surgery. If it is medically reasonable to discontinue aspirin or anticoagulants in preparation for glaucoma surgery, then this should be done. However, the risk of choroidal effusion attributable to anticoagulant use is not yet clear.

During surgery:  Good scleral flap technique, appropriate thickness, multiple sutures on the flap to regulate aqueous outflow, use of cautery to achieve hemostasis, considerate use of antimetabolites, anterior sclerotomy to avoid the ciliary body, and adequate closure of the conjunctiva are all important measures to minimize intraoperative bleeding and hypotony during glaucoma surgery.

Drainage devices: For non-valved devices, the tube should be ligated with dissolvable polyglactin suture at the time of surgery, or two-stage surgery should be performed with the tube remaining in the subconjunctival space outside the eye and being placed into the anterior chamber at a later time. These techniques allow time for the formation of a fibrous capsule around the plate, avoiding excessive filtration in the early post-operative period and thereby minimizing hypotony and its related sequelae.

High-risk patients:  Prophylactic sclerotomies should be performed as a preventive measure in patients with nanophthalmos, Sturge-Weber syndrome, or previous postoperative choroidal effusions.

Post-operative care: Topical and systemic aqueous suppressants should be discontinued, and early laser suture lysis should be avoided. 


Intra-operative hemorrhage is characterized by the development of positive pressure, visualization of an enlarging dark mass obscuring the fundus reflex, and tendency to extrude eye contents.

Post-operative hemorrhagic detachments are characterized by sudden, excruciating throbbing pain with an immediate loss of vision; both symptoms are almost pathognomonic.

Intraocular pressure can be normal, low, or elevated; as a rule, low IOP accompanies serous detachments, and high IOP accompanies hemorrhagic choroidal detachments.


  • The anterior chamber (AC) can be of normal depth, or it can be shallow or flat.
  • The fundus examination shows choroidal detachment.
  • Intraoperative hemorrhages can be complicated by loss of eye contents, resulting in vitreous, retina, or lens remnants incarcerated in the surgical incision or visible in the AC.
  • A non-rhegmatogenous retinal detachment can be superimposed to a choroidal detachment and characterized by shifting subretinal fluid.
  • Choroidal detachments are non-tremulous.
  • Retinal vessels look normal.
  • Ora serrata may be visible without indentation.
Resolving inferior choroidal effusion in setting of improving post-operative hypotony. This patient is a 77M with POAG s/p Ahmed glaucoma valve OS.  Left:  B-scan ultrasonography (US) on post-operative day 3, with intraocular pressure of 4 by Goldmann applanation tonometry.  Right:  B-scan US at post-operative week 2.


Symptoms of choroidal effusions vary among individuals:

  • Serous: Small, peripheral effusions may be asymptomatic, with minimal to no shallowing of the anterior chamber. Large effusions may cause refractive changes from anterior displacement of the lens-iris diaphragm and resultant myopia, or they may cause significant reduction in visual acuity by encroachment into the visual axis.  
  • Hemorrhagic: Unlike serous choroidal effusions, which typically develop painlessly, hemorrhagic choroidals generally have an abrupt onset with severe pain and marked reduction in visual acuity. When hemorrhagic choroidals are associated with high IOP, hyperosmotic agents and aqueous suppressants are recommended. 

Clinical diagnosis

Elevated in a four-lobed presentation because of firm attachments of the choroid to the vortex veins.

Hemorrhagic kissing choroidal detachments in two patients. In both patients, these images were captured at a follow-up visit after surgical repair of a traumatic globe injury.  Left:  B-scan US performed on an elderly female with hemorrhagic choroidals.  Right:  B-scan US performed on a young male with hemorrhagic choroidals.

Diagnostic procedures

B-scan echography helps to differentiate choroidal effusions from retinal detachments.

On echography, effusions are notable for their anterior angle and extension to the ora serrata. Ultrasonography offers a method for detecting a small accumulation of fluid in the supra-ciliary/choroidal space not readily apparent on clinical examination.

Stage the detachment

  • The extent of choroidal detachment can be limited to one or more sectors, with the lobe(s) limited by the fibrous attachments corresponding to the vortex veins.
  • Annular detachments involve the circumference for 360°.
  • A large degree of fluid accumulation can cause contact between lobes within the visual axis, with retina-to-retina contact centrally (kissing choroidals).
  • A small amount of fluid accumulation can cause a flat and anterior detachment, visible only with ultrasound biomicroscopy (UBM).

Differential diagnosis

  • Uveal effusion syndrome
  • Idiopathic ciliochoroidal effusion
  • Pseudophakic or aphakic pupillary block
  • Choroidal melanoma
  • Retinal detachment
  • Malignant glaucoma


Choroidal effusions after glaucoma surgery are often managed conservatively, and the approach varies depending on underlying etiology.

Close observation of post-operative serous chroroidal detachment is frequently appropriate, as IOP may gradually rise. Most effusions resolve spontaneously if they are limited in size and duration. In this situation, they do not affect surgical prognosis or visual outcomes.

General treatment

As soon as the diagnosis is confirmed, topical corticosteroids, cycloplegics, and mydriatics should be prescribed for patients.

Other treatments for an over-filtering bleb include application of a bandage contact lens, injection of a high-density viscoelastic, or use of compression sutures.

Medical therapy

In the presence of inflammation, the eye is treated aggressively with topical or oral steroids. In the presence of over-filtration, steroids are tapered quickly or discontinued to promote bleb scarring. Cycloplegic agents are used to deepen the anterior chamber by rotating the ciliary body posteriorly.


Surgical drainage indications: Flat anterior chamber, decreased vision, long-lasting choroidal effusions, appositional choroidals, and suspected suprachoroidal hemorrhage. When planning to surgically drain hemorrhagic choroidal detachments resulting from ocular trauma, it is typical to wait 10-14 days after the inciting event to allow liquefaction of the clotted blood to occur.

Surgical drainage technique: The location of maximal fluid accumulation should be noted pre-operatively to determine the optimal drainage site(s). Steps of the procedures are listed.

  1. A conjunctival peritomy is performed.
  2. Starting 3 or 4 mm posterior to the limbus, a partial-thickness radial incision is made in the sclera, extending 2- to 3-mm in length.
  3. The incision is deepened until the suprachoroidal space is entered and fluid is released. (The fluid is clear and yellowish in serous choroidals or dark red with blood clots in hemorrhagic choroidals).
  4. The incision’s edges may be pulled apart by forceps or cautery to facilitate fluid egress.
  5. The sclerotomy site is left open with closure of overlying conjunctiva.
  6. A second sclerotomy may be needed to drain fluid from another quadrant.
  7. Throughout the procedure, the eye should be kept pressurized with injection of balanced salt solution, a viscoelastic substance in the anterior chamber, or an anterior chamber maintainer.

Follow up

Post-operative visits should include assessment of visual acuity, anterior chamber depth, and IOP, as well as careful evaluation of the choroidal detachment.


Serous choroidal detachment or suprachoroidal hemorrhage can result in phthisis, retinal detachment, cataract formation, or intractable secondary glaucoma. 


The prognosis is guarded. In general, a correlation exists between the severity and extension of the detachment and the prognosis.

Even with treatment, loss of functional vision can occur in 10-80% of patients.

In general, the prognosis for patients with choroidal hemorrhage is definitely worse than for those with serous choroidal detachments, especially when choroidal hemorrhage occurs intraoperatively, as severe functional damage is frequent.


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