Detection of Occludable Angles with the Pentacam and the Anterior Segment Optical Coherence Tomography

Primary angle closure glaucoma (PACG) is known to be highly prevalent among some ethnic groups, especially those of Mongolian descent.1-5 Foster and Johnson2 have estimated that 1.7 million people in China are bilaterally blind from glaucoma and 91 % of them are attributable to PACG. The number of people with a predisposing risk of anatomically occludable angles is estimated to be 28.2 million, and 9.1 million with significantly closed angle.3 For several decades, it is believed that proper prophylactic laser peripheral iridotomy prevents occludable angles from the angle closure attack.6,7 As damage by acute angle closure is irreversible; screening for occludable angles in endemic areas of angle closure is important. PACG is diagnosed in cases that have an occludable angles combined with glaucomatous optic neuropathy and consistent visual field defect. Gonioscopy is the gold standard for identifying occludable angles, but it requires expertise of a highly skilled examiner. In addition, it is a relatively subjective technique, and intra- and inter-observer reproducibility is poor. There are no uniform gonioscopic criteria to identify angles that require treatment.8,