Saad 2016.

Study characteristics
Patient Sampling	Case‐control study; part of a prospective study evaluating clinical, topographic, tomographic, and biomechanical characteristics of people with keratoconus and keratoconus suspect at the Rothschild Foundation, Paris, France. The study included healthy people and people with keratoconus suspect.
Patient characteristics and setting	119 eyes of 176 people from the Department of Ophthalmology of the Rothschild Foundation were included and separated into 2 groups: normal and keratoconus suspect. The 2 groups were divided based on the results of the Nidek Corneal Navigator (NCN) automated corneal classification software in the OPD‐Scan (Nidek Co. Ltd., Gamagori, Japan). The keratoconus suspect group was composed of 62 topographically normal eyes of people with keratoconus in the fellow eye. The normal group was composed of 114 eyes of 57 people with post‐myopic LASIK who had 4‐year follow‐up, with no postoperative complications such as ectasia. Only the preoperative topographies were considered in the normal group.
Index tests	Discriminant analysis, combining Placido (topography) and corneal wavefront data to detect early forms of keratoconus and to classify corneas as healthy, keratoconus suspect, or keratoconus.
Target condition and reference standard(s)	The article did not mention who made the diagnosis of keratoconus or keratoconus suspect; however, all cases were separated in the 2 groups before the discriminant analysis.
Flow and timing	It was unclear whether all participants received the same reference standard. All cases did receive the same index test, and all data were included in a 2 × 2 table.
Comparative	Not applicable
Notes	No funding source mentioned.
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?	No
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)
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	Unclear
Was the model designed in an appropriate manner?	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?			Unclear
DOMAIN 3: Reference standard
Is the reference standard likely to correctly classify the target condition?	Unclear
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
Could the reference standard, its conduct, or its interpretation have introduced bias?		Unclear risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			Unclear
DOMAIN 4: Flow and timing
Did all patients receive the same reference standard?	Unclear
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		Low risk
DOMAIN 5: Comparative