| Study characteristics |
| Patient Sampling |
Single centre, retrospective, case‐control study. The control group consisted of refractive surgery candidates with normal clinical and topographic features. Early keratoconus was defined as local corneal steepening and asymmetric astigmatism, or the contralateral eye was diagnosed with keratoconus. It also included people with keratoconus. |
| Patient characteristics and setting |
Data set consisted of subclinical keratoconus and keratoconus eyes. |
| Index tests |
A predictive index, Sirius Keratoconus Index (SKI), was constructed using LASSO and Logistic regression analyses based on topographic, pachymetric, and aberrometry variables of the Sirius. The cut‐off value of the SKI was set at 0.44. |
| Target condition and reference standard(s) |
Unclear how the cases were diagnosed. |
| Flow and timing |
Unclear whether all cases received the same reference standard. All cases were included in the index test. 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? |
No |
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| Was a case‐control design avoided? |
No |
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| Did the study avoid inappropriate exclusions? |
No |
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| Could the selection of patients have introduced bias? |
|
High risk |
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| Are there concerns that the included patients and setting do not match the review question? |
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High |
| DOMAIN 2: Index test (All tests) |
| Were the index test results interpreted without knowledge of the results of the reference standard? |
Unclear |
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| If a threshold was used, was it pre‐specified? |
Yes |
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| Was the model designed in an appropriate manner? |
Unclear |
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| Could the conduct or interpretation of the index test have introduced bias? |
|
Unclear 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 standard likely to correctly classify the target condition? |
Unclear |
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| Were the reference standard results interpreted without knowledge of the results of the index tests? |
Unclear |
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| 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? |
|
|
Low concern |
| DOMAIN 4: Flow and timing |
| Did all patients receive the same reference standard? |
Unclear |
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| Were all patients included in the analysis? |
Yes |
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| Could the patient flow have introduced bias? |
|
Unclear risk |
|
| DOMAIN 5: Comparative |
| Were different AI tests were developed and interpreted without knowledge of each other. |
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| Are the proportions and reasons for missing data similar for all index tests? |
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