Plateau Iris Syndrome is a form of angle closure more common in younger female patients. The pathology is thought to be due to anteriorly positioned ciliary processes pushing the peripheral iris forward leading to angle closure. A double hump sign is seen on indentation gonioscopy. During indentation, the peripheral iris drapes over the anteriorly displaced ciliary processes and creates a sign wave formation with elevation, followed by a downward slope in the mid-periphery of the iris and then a second elevation along the iris towards the pupillary margin. Our treatment of choice is to perform cataract extraction with endocyclophotocoagulation which appears to be a more definitive treatment of the root cause of this disease process.
Speaker: Dr. Malik Y. Kahook, Professor of Ophthalmology, University of Colorado, USA
Transcript
00:00
This is Malik Kahook from the University of Colorado with a new addition of one slide in five minutes. The topic is plateau Iris syndrome. Plateau Iris syndrome is a form of angle closure more common in younger female patients. These patients tend to be less hyperopic than those with classic primary angle closure. There is also often a family history of angle closure, and the inheritance pattern appears to be autosomal dominant with incomplete penetrance. A classic teaching is for the presence of anteriorly positioned ciliary processes which push the peripheral Iris forward leading to angle closure.
00:38
The anatomical findings in plateau Iris syndrome might be caused by a more anterior junction of the iris dilator muscle and ciliary epithelium, which may contribute to bunching of the iris and occlusion of the angle at the time of dilation. This is commonly described in textbooks as an anterior displacement of the iris insertion on the ciliary body. Some textbooks also split the findings into two different categories with the first being plateau Iris configuration. This is an appositional or narrow angle confirmed by Gonioscopy prior to LPI with a deep anterior chamber and flat iris.
01:13
And plateau Iris syndrome, which is found after a pain iridotomy has been performed eliminating the relative pupillary block but with evidence of angle closure persisting in a deep central anterior chamber. On exam, the central anterior chamber is deep while the drainage angle is occluded. This is a distinguishing feature compared to primary angle closure. The classic examination question for trainees is the finding of a double hump sign on Gonioscopy or ultrasound biomicroscopy and I will point to the double hump sign here on the Gonioscopic photo showing the double hump in the peripheral Iris. You can also see anterior displacement of the ciliary processes which is pushing the peripheral Iris forward to occlude the anterior chamber and place the peripheral Iris over the trabecular meshwork.
02:06
Peripheral anterior synechiae often formed in reverse from schwalbe’s line to the spur compared to classic pupillary block angle closure where PAS form from posterior to anterior. Management includes laser peripheral iridotomy, however angle closure is still possible despite a patent PI and other steps such as cataract extraction and iridoplasty are often needed to further deepen the angle, we find that aerotow plasti is really just a temporizing measure and have not utilized this in our clinics for the past decade. Our choice is to perform cataract extraction with endo cyclo photocoagulation, which appears to be a more definitive treatment of the root cause of this disease process. Consider visiting keogt.com for more educational material, as well as the YouTube channel which contains all of the one slide and five minute lectures. You can also get in touch with me on Twitter or Instagram. Thank you very much.
Plateau Iris Syndrome
•A form of angle closure more common in younger female patients.
•Classic teaching: Anteriorly positioned ciliary processes push the peripheral iris forward leading to angle closure.
•The anatomical findings in plateau iris syndrome might be caused by a more anterior junction of the iris dilator muscle and ciliary epithelium which may contribute to bunching of the iris and occlusion of the angle at the time of dilation. This is commonly described in textbooks as an anterior displacement of the iris insertion on the ciliary body.
•Plateau Iris Configuration (PIC): Appositional or narrow angle is confirmed by gonioscopy prior to LPI with a deep anterior chamber and flat iris.
•Plateau Iris Syndrome (PIS): Patent iridotomy has eliminated the relative pupillary block but evidence of angle-closure persists with a deep central AC.
•On exam, the central anterior chamber is deep while the drainage angle is occluded, a distinguishing feature compared to primary angle closure.
•A double hump sign is seen on indentation gonioscopy and UBM.
•PAS often form in reverse from Schwalbe’s line to the spur compared to classic pupillary block angle closure where PAS form from posterior to anterior.
•Management includes LPI, however angle closure is still possible despite a patent PI and other steps (cataract extraction, iridoplasty) are needed to further deepen the angle.
•Our choice is to perform cataract extraction with endocyclophotocoagulation which appears to be a more definitive treatment of the root cause of this disease process.