The performance of limbal chamber depth estimation in detection of primary angle closure
| Location | N America17 | Greenland6 | Australia18 | India7 | Taiwan8 | Mongolia | ||||
| Setting | Clinic | Community | Clinic | Clinic | Community | Community | ||||
| Subjects | 135 | 311 | 1113 | 96 | 562 | 1717 | ||||
| LCD/PCT cut off | ⩽¼ | ⩽¼ | ⩽0.2 | <¼ | ¼ to ½ | <¼ | ⩽25% | ⩽ 5% | ||
| Sensitivity | 24/29 (83%) | 51/56 (91%) | 24/27 (89%) | 13/21 (62%) | 15/16 (94%) | 9/16 (56%) | 139/140 (99%) | 26/28 (91%) | ||
| Specificity | 89/106 (84%) | 136/255 (53%) | 3/1086 (99%) | 67/75 (89%) | 282/487 (58%) | 461/487 (95%) | 1022/1560 (66%) | 1564/1689 (93%) | ||
| “Gold standard” | ACD ⩽2.00 mm | ACD ⩽2.00 mm | Gonioscopy | Gonioscopy | Diagnosis of “PACG” | Gonioscopy | Gonioscopy, disc and field examination | |||
↵LCD/PCT=the ratio of depth of the anterior chamber at the temporal limbus to the adjacent peripheral corneal thickness used as the criterion of screening test failure.
↵Gonioscopy was carried out only if LCD/PCT ⩽0.3.
↵Known cases of primary angle closure excluded.
↵Primary angle closure glaucoma: diagnosed irrespective of disc damage or visual field loss, if angle appeared narrow on gonioscopic examination and the intraocular pressure >18 mm Hg or positive dark room prone provocation test. Three subjects with previous attacks of acute angle closure treated by iridectomy were included.
↵For detection of occludable drainage angle as defined in text. Gonioscopy was not possible in 17 people.
↵For detection of occludable drainage angle and glaucomatous visual morbidity.