Dr. Shrushti
Resident, Abmh
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Retina Vitreous › Vitreous substitutes
Surgical peripheral iridotomy
An inferior PI (Ando's PI) is performed in aphakic or pseudophakic eyes that are filled with silicone oil, usually following retinal detachment surgery. Silicone oil is lighter than the eye's natural aqueous humor and tends to float upwards. If a traditional superior (top) PI is used, the oil bubble floats up and blocks the hole, trapping fluid and causing dangerous pressure spikes (pupillary block glaucoma).The Solution: An inferior PI (at the 6 o'clock position) allows the heavier aqueous fluid to flow freely underneath the trapped silicone oil, equalizing pressure and preventing pupillary block.