Cataract surgery for residual angle closure after peripheral laser iridotomy.

PURPOSE: To investigate the frequency of residual angle closure after resolution of pupillary blocking by laser peripheral iridotomy and the effects of subsequent cataract surgery to resolve angle closure completely.
DESIGN: Retrospective, consecutive, interventional study. PARTICIPANTS: Among 70 eyes treated with laser iridotomy, 13 with residual angle closure were treated with cataract surgery.
METHODS: The provocative test of angle closure by prone position in a dark room for 1 hour was performed; increases in tension of > or =8 mmHg, 6 or 7 mmHg, and < or =5 mmHg were considered to be positive, suspected positive, and negative, respectively. Configuration of the anterior chamber was examined using ultrasound biomicroscopy (UBM). MAIN OUTCOME MEASURES: Intraocular pressure (IOP), response to the dark room prone position test, and morphologic analysis by UBM were evaluated before and 3 months after cataract surgery.
RESULTS: Residual angle closure after iridotomy was seen in 27 (38.6%) of 70 eyes; this was confirmed functionally by the dark room prone position test and morphologically by UBM. Eyes with IOP of > or =20 mmHg or with a glaucomatous visual field defect before iridotomy had a significantly higher incidence of residual angle closure after iridotomy than eyes without these findings (P<0.05). In all the eyes with residual angle closure after iridotomy, the response to the prone position test became negative after cataract surgery, with significant lowering of IOP (P<0.01).
CONCLUSIONS: Residual angle closure after iridotomy was common, especially in eyes with primary angle closure and poorly controlled IOP or glaucomatous optic neuropathy. Cataract surgery was effective to resolve completely the residual angle closure after iridotomy and lower IOP.