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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Approach Considerations

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


Laboratory Studies

Perform an inflammatory and/or infectious workup as required.


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


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.


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.


Histologic Findings

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



No formal staging scale exists.