Peripheral Anterior Synechia Workup

Updated: Jul 26, 2016
  • Author: Andrew J Tatham, MBChB, FRCOphth, FRCSEd, FEBO; Chief Editor: Hampton Roy, Sr, MD  more...
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Workup

Laboratory Studies

For peripheral anterior synechiae (PAS), perform an inflammatory and infectious workup as required.

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Imaging Studies

See the list below:

  • Ultrasound biomicroscopy

    • Useful in evaluating the angle in angle-closure glaucoma

    • Can delineate peripheral anterior synechiae and determine their extent

    • May demonstrate a small space between peripheral anterior synechiae and the trabecular meshwork, suggesting that the trabecular meshwork may still be capable of normal function

    • May be useful in demonstrating supraciliary fluid

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

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Other Tests

See the list below:

  • Provocative testing - This test 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.

    • 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 (alpha-adrenergic antagonists)

      • Blocks iris dilator muscles, resulting in miosis with no effect on outflow facility

      • Decrease in intraocular pressure implies miosis has reduced pupil block

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Procedures

An anterior chamber paracentesis with subsequent injection of viscoelastic into the anterior chamber in an attempt to deepen a narrow angle can be used to differentiate appositional closure versus synechial closure. By deepening the angle, a better view of the angle could be gained in the operating suite to determine the presence of peripheral anterior synechiae. Sometimes, this procedure may be therapeutic and diagnostic.

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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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