Table 5: Diagnostic Criteria for POAG used in Studies.
| Study Name, | Diagnostic criteria for POAG | Definition of POAG |
|---|---|---|
| Chennai Glaucoma Study Southern India (36) |
Diagnosed using the 3 categories of the International Society of Geographical and Epidemiologic Ophthalmology classification. Category 1: structural and functional evidence. *CDR or CDR asymmetry ≥97.5th percentile of the normal population or a neuroretinal rim width reduced to ≤ 0.1 CDR (between 11-10 or 5-7 o’clock) with a definite visual field defect on automated perimetry consistent with glaucoma Category 2: advanced structural damage + unproven visual field loss for cases where visual fields could not be assessed or had a CDR and CDR asymmetry ≥ 99.5th percentile for the normal population. Category 3: Optic disc not seen; visual field testing impossible. Visual acuity <3/60 and IOP ≥ 99.5th percentile of normal population or visual acuity <3/60 and the eye shows evidence of glaucoma filtering surgery, or medical record were available confirming glaucomatous visual morbidity. |
Definite POAG: 1 of the 3 categories + an open and normal appearing angle on gonioscopy. (Only 1 case was diagnosed based on IOP criterion in this study) |
| Aravind Comprehensive Eye survey Southern India (5) |
Optic nerve damage: †VCDR>0.8 or a narrowest neuro-retinal rim width <0.2 (including classic notching) or asymmetry >0.2 between eyes coupled with a visual field defect on automated perimetry in the matching location In cases where visual fields were not available: Presence of significant optic disc excavation compatible with glaucoma, or end-stage glaucoma with severe central vision loss, or total optic disc cupping |
Evidence of glaucomatous optic nerve damage which included either glaucomatous change in the appearance of the optic nerve head and/or nerve fiber bundle pattern perimetric defects typical of glaucomatous damage. Definition did not rely on IOP |
| Blue Mountains Study Australia (37-39) |
Matching optic disc cupping with rim thinning (CDR ≥0.7 or cup-disc asymmetry ≥0.3) and characteristic visual field loss on automated perimetry. | Optic disc defects and visual field loss on automated perimetry. Definition did not rely on IOP. |
| Barbados Eye Study Barbados, West Indies (35;40;41) |
Optic disc criteria: At least 2 signs of optic disc damage including either a HCDR or VCDR of ≥ 0.7, narrowest remaining neuroretinal rim of 0.1 disc diameters or less, notching asymmetry in CDR between eyes of > 0.2 and disc hemorrhages. | Criteria for definite PAOG were based on the presence of both visual field defects (Humphrey automated perimetery) and optic disc damage in at least 1 eye. Definition did not rely on IOP |
| Baltimore Eye Study USA (42;43) |
Glaucomatous optic nerve damage and visual field defects on automated perimetry or Goldmann perimetry if automated was not possible in the presence of normal angles and in the absence of other likely causes. 97% of all cases were diagnosed using the following criteria: |
A final classification of definite, probable and uncertain-unknown was made after considering glaucomatous optic nerve damage based on appearance of visual fields, optic disc, and nerve fiber layer, angle grade based on slit-lamp examination and gonioscopy. |
| 1. ≥ 2 abnormal visual fields with excellent congruence between fields | Definition did not rely on IOP | |
| 2. End-stage disease with visual acuity ≤ 20/200 and 100% cupping | ||
| 3. ≥ 1 abnormal visual field with some but not perfect confluence between fields and a CDR ≥ 0.8 or a difference between the 2 eyes of ≥ 0.3/ | ||
| 4. ≥ 1 abnormal visual field with some but not perfect congruence between fields | ||
| 5. 1 visual field performed with typical field defects. | ||
| 6. 1 visual field either typically abnormal or compatible with glaucoma and cupping or nerve-fiber layer loss | ||
| 7. asymmetric cupping with a difference between the 2 eyes of ≥ 0.4 | ||
| Beaver Dam Study USA (44;45) |
1. Visual field defects with suprathreshold static perimetry using multiple stimulus patterns. | Definite glaucoma: having at least 2 of the first 3 criteria. |
| 2. CDR ≥ 0.8 or difference in CDR of 0.2 or more in involved eye. | Probable glaucoma: criterion 4 and fewer than 2 of the other 3 criteria in the same eye. | |
| 3. IOP ≥ 22 mmHg | ||
| 4. History of taking drops or having surgery for glaucoma |
*
CDR=cup to disc ratio,
†
VCDR=vertical cup to disc ratio