Postoperative Flat Anterior Chamber Clinical Presentation

Updated: Apr 12, 2019
  • Author: Andrew A Dahl, MD, FACS; Chief Editor: Hampton Roy, Sr, MD  more...
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Presentation

History

Clearly, this topic has an important historical connotation. Prior to the introduction of suture material to create edge-to-edge wound closure, flat and shallow anterior chambers were not uncommon occurrences following anterior segment surgery.

Even the introduction of suture material did not eliminate the problem. Microsurgical techniques, fine needles, and suture material and instrumentation have had an enormous beneficial impact.

Newer sutureless self-sealing corneal incisions have continued to reduce the problem but have not eliminated it.

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Physical

The anterior chamber of the eye contains the anterior chamber, the posterior chamber, and the vitreous cavity. The anterior chamber is bordered anteriorly by the cornea, posteriorly by the front surface of the iris and the lens, and peripherally by the anterior chamber angle, which contains the trabecular meshwork. The anterior chamber is deepest (approximately 3 mm) in its central portion and shallowest at the peripheral insertion of the iris. In humans, its volume is approximately 0.25 mL.

A shallower anterior chamber can be a normal variant commonly seen in hyperopic eyes.

The slit lamp biomicroscope is important to accurately assess the anterior chamber. When a shallow anterior chamber is detected, a thorough history, including previous surgery or trauma, should be obtained. Evaluation of associated factors, including intraocular pressure, gonioscopy, and fundus examination, is important.

The depth of the anterior chamber is estimated as the distance between the posterior surface of the cornea and the front surface of the iris. Usually, it measures 3 mm or more. If the iris appears to be convex and parallels the posterior chamber surface and if the depth of the anterior chamber is less than 2 mm, angle-closure glaucoma is a risk.

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Causes

Causes and management of flat anterior chamber with elevated intraocular pressure

Angle-closure glaucoma

Angle-closure glaucoma is a frequent cause of narrowing of the anterior chamber.

Acute angle closure presents with a painful red eye, significant intraocular pressure elevation, and closure of the angle detected by gonioscopy. Angle-closure glaucoma can indicate pupillary block. Laser iridotomy is indicated and should result in an immediate resolution of the condition with deepening of the anterior chamber. [2] Medical management includes topical pilocarpine drops to constrict the pupil and to break the attack, as well as topical ocular pressure lowering agents, intravenous mannitol or acetazolamide, and topical anti-inflammatory eye drops. Gonioscopy after relief of pupillary block is important to detect residual angle closure.

Chronic angle closure may have a much less dramatic presentation; however, gonioscopy readily determines the diagnosis.

Aqueous misdirection

Malignant glaucoma is most common in hyperopic eyes and in eyes with previous primary angle-closure glaucoma, often with a recent history of intraocular surgery. It is diagnosed when there is shallowing of the central anterior chamber in association with increased IOP and a normal posterior segment examination. This condition is believed to be due to misdirection of aqueous humor flow posteriorly into the vitreous cavity, with an impermeable anterior hyaloid face. Fluid buildup in the vitreous causes a forward force leading to anterior displacement of the lens-iris diaphragm. It may be treated with medical therapy, including topical atropine and aqueous humor suppressants, or surgically with disruption of the vitreous face.

Pseudophakic or aphakic eyes can be treated with Nd-YAG laser capsulotomy and disruption of the anterior hyaloid face. Phakic patients are treated by cataract extraction with intraocular lens implantation, posterior capsulotomy, and vitrectomy. In cases refractory to medical and laser therapy, surgical intervention to remove the vitreous is necessary to increase aqueous flow into the anterior chamber.

Synechial closure from adhesions, neovascularization, or inflammation

Anterior uveitis, with or without infection, can produce anterior synechiae and an apparent shallowing of the anterior chamber. In these instances, appropriate anti-inflammatory therapy and/or anti-infective therapy is indicated.

Posterior synechiae (iris/crystalline lens) may also form and result in pupillary block, iris bombe, and acute angle-closure glaucoma. Posterior synechiae can often be broken with the use of cycloplegic agents.

Surgical synechialysis or laser iridoplasty may be performed when the inflammatory situation has stabilized.

Mature lens causing phacomorphic glaucoma

With development of a mature lens, the lens may swell, leading to shallowing of the anterior chamber.

Lens swelling can lead to pupillary block in the acute phase.

In the late phase, phacomorphic glaucoma can occur without pupillary block as a result of forward movement of the peripheral iris.

Causes include a traumatic cataract, a rapidly progressive senile cataract, or a delay in cataract surgery for a mature lens.

Lens extraction results in normalization of the anterior chamber if permanent synechiae have not formed.

Causes and management of flat anterior chamber with low intraocular pressure

Cataract extraction wound leaks

Following cataract extraction using a clear corneal incision, the surgeon often hydrates the lips of the corneal wound. The resultant stromal edema produced by the hydrophilic stromal collagen assists in creating an initial seal; therefore, the anterior chamber can be maintained at the close of the procedure.

Occasionally, one or more superficial sutures may be used if any question exists as to wound stability.

Hydrated collagen shields alone or in addition to hydrophilic bandage lenses for 24 hours may help wound leaks. Any application of a hydrophilic bandage lens must be accompanied by instillation of appropriate prophylactic antibiotic solution.

Corneal transplantation wound leaks

In the early postoperative period, several possible complications may be encountered. Wound leak is usually associated with poor wound apposition between the graft and the host tissues. A loose suture, wound tissue displacement, or poor wound closure may occur. Seidel testing is helpful in detecting wound leaks.

If the wound dehiscence is large, especially if it is associated with a flattened anterior chamber, resuturing of the wound is indicated. In addition, use of patching or bandage contact lens may be helpful in the case of resuturing.

Use of a viscoelastic gel in the anterior chamber is a helpful technique during resuturing.

Excessive filtration (trabeculectomy)

A soft eye and a shallow anterior chamber in the early postoperative period can be associated with a filtering bleb, either deliberately created following trabeculectomy or an inadvertent bleb in which a leak becomes covered with conjunctiva. [3, 4]

Late-onset bleb leaks can occur after glaucoma filtering surgery. [5]

Intracameral injection of viscoelastic agents or certain gases may be effective in the reformation of the flat anterior chamber. [6]

Pressure patching can help to reduce filtration and to reform the anterior chamber.

Choroidal detachment [7]

If the shallow chamber persists and the intraocular pressure is very low, this may reflect choroidal detachment. Indirect ophthalmoscopy or B-scan ultrasonography can be used to confirm the diagnosis.

Treatment includes topical steroids. [8] Choroidal drainage with or without modification of a filtering bleb may be indicated to avoid long-term sequelae of choroidal detachment and ciliary body dysfunction.

Trauma

Traumatic cyclodialysis cleft formation may be associated with hypotony and shallowing of the anterior chamber.

Corneal perforation with wound leak (as confirmed by a Seidel test) may result in a shallow anterior chamber with hypotony.

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