What is the role of provocative testing in the workup of peripheral anterior synechiae (PAS)?

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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Answer

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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