Table 6

The performance of limbal chamber depth estimation in detection of primary angle closure

Location N America17 Greenland6 Australia18 India7 Taiwan8 Mongolia
Setting ClinicCommunityClinicClinicCommunityCommunity
Subjects 1353111113965621717
LCD/PCT cut off ⩽¼ ⩽¼⩽0.2¼ to ½⩽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 GonioscopyDiagnosis 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.