Peripheral Anterior Synechia Workup

Updated: Mar 19, 2021
  • Author: Maria Hannah Pia U de Guzman, MD, DPBO, FPAO; Chief Editor: Hampton Roy, Sr, MD  more...
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Workup

Approach Considerations

The appropriate management of peripheral anterior synechiae (PAS) depends on the disease process that has led to the formation of the PAS. 

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Laboratory Studies

Perform an inflammatory and/or infectious workup as required.

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Imaging Studies

Ultrasound biomicroscopy [6] or anterior segment imaging (eg, optical coherence tomography [7] )

  • Useful in evaluating the angle in angle-closure glaucoma

  • Can delineate PAS and determine the extent

  • May reveal a small space between the PAS and the trabecular meshwork suggesting that the trabecular meshwork may still be functional

  • May be useful in documenting supraciliary fluid

Corneal specular microscopy - useful in identifying iridocorneal endothelial or posterior polymorphous dystrophy cells

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Other Tests

Provocative testing - measures intraocular pressure while dilating or constricting the pupil to differentiate angle-closure glaucoma from open-angle glaucoma with narrow angles. However, it correctly identifies only 50%-70% of patients with true angle-closure glaucoma.

  • Dark room: Increase in intraocular pressure with mydriasis implies pupil block.
  • Pharmacologic mydriatic test: Increase in intraocular pressure with mydriasis implies pupil block.
  • Thymoxamine and dapiprazole (α-adrenergic antagonists)
    • Block iris dilator muscles, resulting in miosis with no effect on outflow facility.
    • Decrease intraocular pressure, which implies that miosis has reduced pupil block.
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Procedures

A paracentesis with injection of viscoelastic into the anterior chamber done in an attempt to deepen a narrow angle can be used to differentiate appositional closure from synechial closure. By deepening the angle, a better view of the angle can be obtained to determine the presence of PAS. Sometimes, this procedure can be both diagnostic and therapeutic.

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Histologic Findings

Histologic findings depend on the causative agent; they can be fibrovascular, epithelial, endothelial, or inflammatory in nature.

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Staging

No formal staging scale exists.

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