Kim 2014b.

Study characteristics
Patient Sampling	Retrospective case‐control study including early glaucoma, preperimetric glaucoma and healthy controls. If both eligible, one eye per person was randomly selected.
Patient characteristics and setting	Sample size: 204 eyes of 204 participants (72 early glaucoma, 68 preperimetric glaucoma, 64 normal controls) Age: early glaucoma mean ± SD, 56.83 ± 12.73 years; preperimetric glaucoma, 53.12 ± 10.69 years; controls, 51.77 ± 14.44 years; Sex: not reported. Ethnicity: not reported. Setting: general healthcare clinic or glaucoma clinic of the Guri Hanyang University Medical Center from September 2011 through May 2013. Country: South Korea. Ocular comorbidities: patients with co‐existing retinal disease, uveitis, or non‐glaucomatous optic disc neuropathy were excluded. Spectrum of glaucoma severity: the mean ± SD MD and PSD on the VF test were ‐3.08 ± 1.61 and 4.29 ± 2.64 respectively, for early glaucoma; ‐1.02 ± 1.29 and 1.87 ± 0.5 respectively for preperimetric glaucoma. Control participants: first‐degree relatives with glaucoma, no history or evidence of intraocular surgery, IOP < 22 mmHg, a normal optic disc appearance and ophthalmic findings.
Index tests	Optical coherence tomography: Cirrus OCT (Carl Zeiss Meditec, Dublin, CA, USA); software version 6.0. Poor‐quality OCT images such as those with low signal strength (< 70), motion artefact, or decentration were excluded. 7 x 7 mm scanning disc protocol was used to analyse RNFL and GCC parameters. The authors declare no conflict of interest
Target condition and reference standard(s)	Manifest perimetric glaucoma: glaucomatous VF results (defined as a cluster of 3 points with P < 5% on the pattern deviation map in at least 1 hemifield, including at least 1 point with P < 1%; or a cluster of 2 points with P < 1%, and GHT or PSD outside normal limits) and glaucomatous ONH/RNFL appearance (neuroretinal rim loss or notching, focal thinning of the NFL, disc haemorrhages, or vertical elongation of the optic cup). Manifest preperimetric glaucoma: glaucomatous ONH/RNFL appearance (neuroretinal rim loss or notching, focal thinning of the NFL, disc haemorrhages, or vertical elongation of the optic cup) with normal VF results. Visual field test: Humphrey Field Analyzer (Carl Zeiss Meditec, Dublin, CA, USA) 30‐2 SITA standard programme. The fixation losses < 20 %, and false‐positive and false‐negative errors < 15 %, were considered as reliable. Optic disc/RNFL evaluation: dilated funduscopy using a 78‐D lens and stereoscopic optic disc photography.
Flow and timing	No details reported about exclusion and time interval between index and reference test.
Comparative
Notes	None.
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Was a case‐control design avoided?	No
Did the study avoid inappropriate exclusions?	Yes
Could the selection of patients have introduced bias?		High risk
Are there concerns that the included patients and setting do not match the review question?			High
DOMAIN 2: Index Test (All tests)
If a threshold was used, was it pre‐specified?	Yes
Were imaging test's quality assessed?	Yes
Were any conflict of interest avoided	Yes
Could the conduct or interpretation of the index test have introduced bias?		Low risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
Could the reference standard, its conduct, or its interpretation have introduced bias?		Low risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			Low concern
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Unclear
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Unclear
Did all patients receive a reference standard	Yes
Could the patient flow have introduced bias?		Unclear risk