SEROUS CHOROIDAL DETACHMENT

 

INTRODUCTION:

• Terms such as choroidal effusion, ciliochoroidal effusion, choroidal detachment, and ciliochoroidal detachment are used for somewhat similar entities and occasionally mentioned interchangeably in the literature.
• However, choroidal detachment is a broader term than choroidal effusion.
• The terms choroidal effusion, ciliochoroidal effusion, and serous choroidal detachment describe the same entity.
• A choroidal detachment (CD) is defined as abnormal presence of fluid or blood in the suprachoroidal space.
• The suprachoroidal space is the potential space between the choroid and the sclera.
• CD is of in two types—serous and haemorrhagic. Serous choroidal detachments, also known as choroidal effusions, are a frequent complication of glaucoma surgery.
• Glaucoma surgery is the most common cause of choroidal detachments, which may occur in 3-34% of trabeculectomies and 3%-35% of glaucoma implant procedures. Newer techniques such as MIGS have lower incidence of CDs.
• Other causes of choroidal detachment include infection (e.g., herpesviruses, human immunodeficiency virus), inflammation (e.g., posterior scleritis, drug-induced cyclitis, Vogt-Koyanagi-Harada syndrome), malignancy (e.g., primary intraocular lymphoma or metastatic carcinoma), or episcleral venous congestion (e.g., Sturge-Weber syndrome, dural arteriovenous fistula.
• Uveal effusion syndrome is a rare cause of idiopathic choroidal effusions that may involve impaired posterior segment drainage and congenital anomaly of the sclera resulting in scleral thickening.
• Following glaucoma surgery hypotony may occur, resulting in pressure-driven osmotic shifts of serous fluid from the choroidal capillaries into the suprachoroidal space due to decreased vascular permeability.
•  Due to the increased use of antimetabolites, there is increased incidence of persistent choroidals, complicating the postoperative course with prolonged visual compromise, shallow anterior chambers, cataract formation, and bleb failure.
• Choroidal effusions further potentiate hypotony due to reduced aqueous humor production.
• Disturbances in the hydrostatic and oncotic pressure gradients and high permeability of the choriocapillaris result in serum or blood accumulation in the suprachoroidal space. This fluid accumulation leads to thickening of the choroid and the formation of a fluid-filled suprachoroidal layer.
• Low IOP or a disruption to uveoscleral outflow also promotes fluid accumulation within the suprachoroidal space.

SEROUS CHOROIDAL DETACHMENTS:

• Serous choroidal effusions result from transudation of serum into the suprachoroidal space.
• Starling’s equation explains the movement of fluid between the plasma and interstitium. According to this equation, the movement is determined by the relative hydrostatic and oncotic pressures of these compartments.
• Drastic fall in IOP such as that occurring following incisional glaucoma surgery allows fluid to accumulate in the interstitial space, due to a higher capillary pressure relative to interstitial pressure.
• Other factors which can contribute to the formation of choroidal effusions include:
• Inflammation-induced increases in choroidal capillary permeability and high hydrostatic pressure in the choroidal vascular plexus secondary to hypertension.
• Accumulation of proteinaceous serum in the suprachoroidal space disturbs the equilibrium between the oncotic pressure in the interstitium and plasma limits uveal resorption.
• These non-resolving choroidal effusions may result in serous retinal detachment due to failure of the retinal pigment epithelium pump mechanism.

RISK FACTORS FOR SEROUS CDs:

SURGERY

Glaucoma filtration surgery (GFS) [e.g., trabeculectomy or MIGS implantation].

Glaucoma Drainage Device (GDD) implantation [especially valved devices].

Laser peripheral iridotomy.

Retinal surgery (pars plana vitrectomy or scleral buckling procedure).

Any glaucoma surgery with intraoperative or postoperative hypotony.

 

OCULAR MEDICATIONS

Antimetabolite (mitomycin C or 5-fluorouracil) augmented GFS especially in the setting of prolonged hypotony.

Topical aqueous suppressants (e.g., timolol and dorzolamide) after trabeculectomy or GDD implantation.

Topical prostaglandin analogs (e.g., latanoprost, travoprost, and bimatoprost) have been associated with late choroidal effusions following cataract extraction or GFS.

Intravitreal injection of ocriplasmin has also been reported as a cause of choroidal effusion.

 

SYSTEMIC MEDICATIONS

Carbonic anhydrase inhibitors.

Anticoagulants.

Topiramate.

Tamsulosin.

Sulfonamides (e.g., chlorthalidone, sulfamethoxazole-trimethoprim, indapamide)

Antidepressants (e.g., escitalopram, venlafaxine, bupropion)

Angiotensin receptor blockers (e.g., losartan)

Chemotherapeutics (e.g., docetaxol and gemcitabine)

Pergolide (a dopamine agonist used to treat Parkinson’s disease)

Drugs of abuse (e.g., 3,4-methylenedioxymethamphetamine a.k.a. “ecstasy” or MDMA)

 

PRE-EXISTING CONDITIONS

Nanophthalmos

Sturge-Weber syndrome

Hypermetropia

Systemic hypertension

Atherosclerosis

Diabetes mellitus

Prior cataract surgery

Glaucoma

Diffuse choroidal hemangioma

Older age

History of choroidal detachment in the other eye

 

TREATMENT-RELATED FACTORS 

Lower postoperative IOP

Full-thickness filtration surgery

Ocular inflammation

Aqueous suppressant therapy

 

PRIMARY PREVENTION OF CDs:

• Acute glaucoma surgery-related CDs may be prevented by minimizing hypotony, bleeding, and inflammation intra-operatively and post-operatively.
• Pre-operative medications (Carbonic anhydrase inhibitors or osmotic agents) can be used to reduce IOP.
• Intra-operative proper and meticulous surgical technique would avoid the development of CDs.
• The scleral flap should be constructed at 50-75% scleral depth.
• To prevent early hypotony, multiple sutures can be placed in the scleral flap.
• Suture release should be delayed by at least one week.
• A stable anterior chamber can be achieved with a cohesive ophthalmic viscosurgical device or anterior chamber maintainer.
• Antimetabolites should be used carefully, as their use can increase the risk of CD.
• When non-valved GDDs are implanted, the tube should be ligated with dissolvable polyglactin suture intra-operatively, 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.
• Proper water-tight closure of the conjunctiva should be done at the end of the surgery (it can be confirmed by placing a fluorescein strip over the conjunctival wound and doing the Seidel’s test)
• Releasable sutures and restrictive devices may be used to reduce hypotony, but these tools do not prevent choroidal detachment completely.
• Post-operative care: Topical and systemic aqueous suppressants should be discontinued post-operatively, and early laser suture lysis should be avoided.

DIAGNOSIS:

• Post-operative CDs develop around 2-5 days after surgery.
• Small, peripheral effusions are asymptomatic and usually resolve spontaneously.
• Large effusions affect peripheral vision and may occasionally be large enough to obstruct the visual axis.
• Anterior displacement of the lens-iris diaphragm causes a myopic shift and results in secondary angle closure. Appositional choroidal detachments, which extend from the optic nerve to the lens, are more likely to obscure central vision and cause secondary angle closure.
• Young patients are more prone to develop hypotonic maculopathy.
• Persistent hypotonic maculopathy leads to permanent vision loss.

SIGNS & INVESTIGATIONS:

• The AC can be of normal depth, shallow, or flat.
• AC shallowing is typically diffuse, as pressure from choroidal swelling is indirectly transmitted to the posterior surface of the lens via the vitreous body.
• IOP can be normal, low, or elevated in the setting of choroidal detachment. Typically, low IOP accompanies serous choroidal detachments.
• Fundus examination reveals a multi-lobed appearance. Up to four smooth lobes may be visualized, extending to the vortex veins.
• The fluid-filled lobes of serous detachments demonstrate transillumination. Conversely, hemorrhagic detachments do not transilluminate. Choroidal detachments can be distinguished from retinal detachments based on their more anterior location, extension to the ora serrata, and unique morphology resulting from the choroid’s strong attachments at the sites of the vortex veins.
• B-scan ultrasonography can distinguish serous vs. hemorrhagic CD. Serous detachments appear as rounded, peripheral lobes filled with echo-lucent fluid.
• Ultrasound biomicroscopy (UBM) can be used to visualize anterior rotation of the ciliary body associated with CDs.
• UBM can serve a helpful diagnostic role in confusing cases, as it can distinguish secondary angle closure due to choroidal effusions or a choroidal tumor from a pupillary block angle-closure mechanism.
• Occasionally, wide field fundus photography and swept source optical coherence tomography can also be used to detect and monitor choroidal detachments, with improved detection of peripheral CD.

DIFFERENTIAL DIAGNOSIS:

Retinal detachment

Choroiditis

Central serous chorioretinopathy

Choroidal melanoma

Uveal effusion syndrome

Idiopathic ciliochoroidal effusion

Pseudophakic or aphakic pupillary block

Malignant glaucoma

 

MANAGEMENT:

MEDICAL MANAGEMENT

Most CDs resolve spontaneously. Surgical interventions have been found to cause more visual worsening compared to conservative/medical treatment.

Initially, CDs can be treated with steroids and long-acting cycloplegics such as atropine and cyclopentolate).

Topical steroids are used in an effort to increase IOP and control any inflammation which may be contributing to CD. In severe cases that are refractory to topical medications, systemic steroids may be used.

Any medications promoting ocular inflammation should be discontinued.

SURGICAL MANAGEMENT

In case of wound leaks, a bandage contact lens or suture(s) placed with a tapered (blood vessel) needle can be used to close leaking areas, if the AC is still formed and deep.

If there is an over-filtrating trabeculectomy, transconjunctival sutures may be placed using a tapering needle to secure the scleral flap.

The AC can be reformed by inserting a cohesive or ultracohesive viscoelastic material (e.g., Healon 5 or Healon GV, respectively) through the already-formed intraoperative paracentesis track. In some instances, multiple viscoelastic injections may be necessary to maintain AC depth and IOP.

Injections are performed under topical anesthesia, and IOP should be measured afterward to monitor for ocular hypertension due to over-installation of viscoelastic.

SURGICAL DRAINAGE OF CHOROIDAL DETACHMENTS IS INDICATED IN THE FOLLOWING CASES

Flat anterior chamber

Persistent corneal edema with a shallow anterior chamber

Significant eye pain

Elevated IOP refractory to medical management

Longstanding choroidal effusion

Appositional choroidal effusion and/or apposition of the central retina

Hemorrhagic choroidal detachment

Decreased vision

 

• Drainage procedures involve deepening the AC while choroidal fluid egresses out of a full-thickness scleral incision behind the limbus.
• First, a tangential conjunctival incision is made 3-6 mm from the limbus in the quadrant where the effusion is most substantial; a 2-3 mm radial sclerectomy is then placed 3-4 mm posterior to the limbus.
• Choroidal fluid egresses spontaneously and/or with assistance by holding the incision open with forceps or gently depressing the adjacent sclera with a cyclodialysis spatula.
• Finally, the AC is deepened by injecting saline solution via a paracentesis incision.
• This procedure has a reported 77% success rate by 12 months follow-up, defined as complete resolution of the choroidal detachment, normalization of anterior chamber depth, and resolution of hypotony. Most patients had improved visual acuity as well.
• Cataract extraction is part of treating CD. When a visually significant cataract is present in combination with CD, then combined cataract extraction and CD drainage should be performed. Cataract extraction may be considered for non-resolving choroidal detachment, as this may in some cases result in resolution.

PROGNOSIS:

Serous choroidal effusions are usually benign and do not significantly reduce visual acuity.

A large, persistent effusion, however, may cause significant morbidity, particularly when it is associated with hypotony maculopathy or serous retinal detachment.