In plateau iris configuration, laser peripheral iridotomy (LPI) fails to prevent recurrent angle closure because the primary mechanism is:

• A Persistent pupillary block due to lens-iris apposition
• B Failure of aqueous to exit through the LPI site
• C Progressive accumulation of proteinaceous material in the angle
• D Anteriorly rotated ciliary processes mechanically displacing the peripheral iris against the trabecular meshwork ✓

Explanation

In plateau iris configuration, the ciliary processes are anteriorly rotated and physically support the peripheral iris against the trabecular meshwork even after LPI relieves pupillary block. The iridotomy opens the blocked aqueous pathway but does not alter the abnormal ciliary process anatomy. On ultrasound biomicroscopy (UBM), the diagnosis is confirmed by demonstrating anteriorly rotated ciliary processes that 'tent' the peripheral iris. Treatment requires argon laser peripheral iridoplasty (ALPI) to thermally shrink the peripheral iris stroma and deepen the angle recess, or surgical options in refractory cases.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.