Table 1

Details of the seven population studies included for analysis

Author, area, yearAges surveyed (response rates)Ratio POAG to PACGMethod of anterior chamber angle examinationGonioscopic definition of an occludable angleDiagnostic definition of PACGOverall PACG prevalence with age-specific prevalence if given
Bonomi, Egna-Neumarkt, Italy, 1998, 2000* 11 18 40+ (73.9%)3.2:1Slit lamp screening then gonioscopy if glaucoma suspected (by disc exam or visual field testing or IOP≥22 mm Hg)‘Chamber angle partially or totally closed’ or ‘a very narrow angle prone to occlusion (Shaffer grade 0)’; ‘the cases of glaucoma with a narrow but open (Shaffer grade 1 or 2) in the absence of goniosynechiae and with no evidence of previous episodes of angle closure were classified as open-angle glaucoma’Angle + at least two of: IOP≥22 mm Hg, GON, GVFD
  • 26/4297: 0.605%

  • 40–49: 0%

  • 50–59 0.65%

  • 60–69: 0.65%

  • 70+: 1.23%

Cedrone, Ponza, Italy, 1997* 12 40+ (84.3%)2.6:1Slit lamp screening then gonioscopy if shallow AC or suspicious optic disc or IOP >20 mm Hg‘PACG is the angle equal to or less than grade 2’ (Becker–Shaffer)Angle + GVFD + at least one of: IOP>20 mm Hg, GON
  • 10/1034: 0.967%

  • 40–49: 0%

  • 50–59: 1.74%

  • 60–69: 0.64%

  • 70–79: 1.29%

  • 80+: 2.50%

Dielemans, Rotterdam, The Netherlands, 1994* 13 55+ (70.9%)NASlit lamp examination, gonioscopy if glaucoma suspected by visual field testing‘A Goldmann three-mirror contact lens was used to judge if the anterior chamber angle was open following the Shaffer grading system and to determine the degrees of pigmentation and the presence of other abnormalities’No definition, but ‘no person with a narrow angle had glaucomatous visual field defects’0/3062: 0% (but three patients developed AAC after dilation)
Friedmann, Salisbury, USA, 200614 (Friedman et al, unpublished work)73–92 (98.6%)17:114 Gonioscopy if glaucoma known or suspected by suspicious disc, abnormal visual field or IOP≥22 mm Hg‘Angle closure glaucoma was present if the pigmented trabecular meshwork was visible for 90 degrees or less or peripheral anterior synechiae were present without evidence of prior surgery or inflammatory disease’14PACG was diagnosed if the pigmented (posterior) trabecular meshwork was not visible for 180 degrees or more or PAS were present (Friedman et al, unpublished work)Angle + GON ± GVFD
  • 8/1233: 0.649%14 or

  • 19/1233: 1.541%β (Friedman et al, unpublished work, 2011)

Mitchell, Blue Mountains, Australia, 199615 49+ (82.4%)10.8:1All slit lamp examination, gonioscopy if GVFD‘Shaffer grade 1 or less was graded as angle closure glaucoma’Angle + GVFD and GON10/3654: 0.274%
Nizankowska, Wroclaw, Poland, 200516 40–79 (80.8%)20.7:1All slit lamp screening then gonioscopy if glaucoma suspected or Van Herrick less than one-fourth corneal thickness‘An angle in which the posterior trabecular meshwork cannot be seen throughout three-quarters or more of the angle circumference’ made in the primary position without indentationAngle + IOP with GON or GVFD3/4853: 0.062%
Tielsch, Baltimore, USA, 1991* 17 40+ (79.2%)6.4:1All slit lamp examination then gonioscopy if glaucoma suspected (IOP≥21 mm Hg, suspicious disc or VF, or shallow AC)‘…grade of iridocorneal angle (open vs narrow/closed) based on gonioscopy’Angle + GVFD or GON25/5308: 0.471%
  • * Study included in PACG prevalence analysis by Quigley and Broman, 2006;1 for the ratios of POAG to PACG, all cases of normal pressure glaucoma were counted as POAG cases (if reported separately); NA: not applicable; β depending on gonioscopic definition, 19/1233 cases were used for the prevalence analysis as this is consistent with the currently accepted definition for an occludable angle for PACG, see Discussion section.

  • AAC, acute angle closure; AC, anterior chamber; GON, glaucomatous optic neuropathy; GVFD, glaucomatous visual field defect; IOP, intraocular pressure; PACG, primary angle closure glaucoma; PAS, peripheral anterior synechiae; POAG, primary open angle glaucoma; VF, visual field.