Table 1 PICOS criteria for inclusion and exclusion of studies
Parameter | Inclusion criteria | Exclusion criteria |
|---|---|---|
Participants | Healthy individuals; individuals with type 1 or type 2 diabetes without ocular complications; individuals with diabetes and ocular complications | Individuals with ocular complications in the absence of diabetes |
Interventions | No interventions or treatment before sample collection | Treatment or any drug intervention at the time of sample collection |
Comparators | Controls versus Complications; Controls versus Diabetes; Diabetes versus Complications | Longitudinal time points (baseline vs endpoint) |
Outcomes | Biomarkers with actual concentrations reported in tear-fluid | Studies not reporting biomarkers and/or concentrations for the reported biomarker |
Study design | Case–control and observational studies | Non-original articles (conference abstracts, proceedings papers, reviews, systematic reviews, protocols, meta-analyses), drug interventions |