# Table 1 Summary of main features of models combining OCT parameters for the diagnosis of early glaucoma

Model Analytical Method Proposed Combination Predicted Probability Cutoff Points AUC 95% CI width Strength Weakness Validation
GSDI [37] Multivariable logistic regression Average RNFL+GCC; focal loss volume RNFL+GCC; VCDR Not provided Improved diagnostic ability Inter-variable collinearity Internal
OCT Glaucoma Diagnostic Calculator [39] Multivariable logistic regression Age, color code for SN, ST, and min GCIPL, CDR, and values of CDR, VCDR, IT GCIPL and inferior quadrant RNFL. < 0.3 = low;
0.3–0.6 = intermediate;
> 0.6 = high
0.046 Improved diagnostic ability Inter-variable collinearity Internal
UNC OCT Index [36] Exploratory Factor Analysis; multivariable logistic regression Composite RNFL (average, superior and inferior quadrants), composite ONH (VCDR, CDR, rim area), composite GCIPL (all 8 parameters), age ≤0.34 = low; > 0.34 = high 0.011 Minimized inter-variable collinearity, improved diagnostics ability Some information in the original set of variables may be lost when running the factor analysis Internal, external
Baskaran et al. [32] Classification And Regression Tree RNFL (superior, inferior and nasal quadrant, symmetry); ONH (disc area, VCDR, cup volume) Not provided 0.01 Low misclassification rate; improved diagnostic ability Inter-variable collinearity Internal
Baskaran et al. [32] Linear Discriminant Analysis RNFL (average, IQ, SQ); ONH (VCDR, CDR, disc and rim area) Not provided 0.02 Low misclassification rate; improved diagnostic ability Inter-variable collinearity Internal
Blumberg et al. [31] Logistic regression Disc area; RNFL (superior quadrant, clock-hours 8, 12, 1, 6); age Not provided 0.247 Improved diagnostic ability Wide AUC 95% CI Internal
Fang et al. [30] Logistic regression Average RNFL, VCDR, rim area Not provided 0.109 Variables chosen arbitrary. Wide AUC 95% CI. Inter-variable collinearity. No
Huang et al. [33] Linear Discriminant Analysis RNFL (ST1 and 2, NU2, IT1), disc area, standard deviation of superior and inferior hemispheric GCC ≤0.131 0.045 Improved diagnostic ability Inter-variable collinearity No
Yoshida et al. [35] Random Forest classification ONH, RNFL, and GCIPL Not provided 0.028 Improved diagnostic ability Risk of overfitting Internal
1. AUC = area under the curve; CI = confidence intervals; GSDI = Glaucoma Structural Diagnostic Index; RNFL = retinal nerve fiber layer; GCC = ganglion cell complex; VCDR = vertical cup-to-disc ratio; GCIPL = ganglion cell-inner plexiform layer; CDR = cup-to-disc ratio; UNC = University of North Carolina