Table 4. Cut-off point, specificity, and sensitivity values identified in previous study.
| Study | Device | Reference surface | Elevation values(μm) | Normal control | FFKC or KC suspect | KC | Cut-off value (μm) | Sensitivity | Specificity |
|---|---|---|---|---|---|---|---|---|---|
| M Itoi et al. [38] (Normal n = 88, FFKC n = 13, KC n = 29) | SS-OCT CASIA 1000 | BFS (central 5 mm of the anterior or posterior cornea) | anterior | 5.43 ± 1.38 (n = 88) | 13.85 ± 7.23 (n = 13) | 44.00 ± 22.15 (n = 29) | 8.00 | 85% | 96% |
| posterior | 10.00 ± 2.82 | 22.69 ± 12.07 | 89.93 ± 41.93 | 13.00 | 85% | 86% | |||
| Rao et al. [39] (Normal n = 50, KC suspect n = 60, KC n = 15) | Orbscan II | BFS | anterior | 0.005 ± 0.002 | 0.009 ± 0.007 | 0.013 ± 0.010 | - | - | - |
| posterior | 0.021 ± 0.006 | 0.035 ± 0.015 | 0.044 ±0.025 | 40 | - | - | |||
| I Kovács et al. [23] (Normal n = 41, KC n = 41) | Pentacam | BFS (central 5 mm of the anterior or posterior cornea) | anterior | 2.7 ± 2.3 | - | 33.3 ± 28.6 | - | - | - |
| posterior | 5.7 ± 5.5 | 55.8 ± 33.2 | 15.5 | 95.1% | 94.3% | ||||
| I Kovács et al. [29] (Normal n = 70, KC n = 44) | Pentacam | BFS, BFTE (fixed 8-mm-diameter) | Posterior elevation BFS 8 mm | 1.38 ± 5.75 | - | 42.68 ± 33.44 | 15.5 | 91% | 98% |
| Posterior elevation BFTE 8 mm | 5.66 ± 5.02 | 67.57 ± 48.57 | 10.5 | 91% | 95% | ||||
| Orucoglu F et al. [40] (normal n = 513, KC n = 656) | Pentacam | BFS (8-mm-diameter) | Anterior | 3.59 ± 2.43 | - | 16.28 ± 12.14 | 8.5 | 71.6% | 100% |
| at thinnest point | Anterior elevation at thinnest point | 2.29 ± 1.80 | 20.53 ± 14.33 | 5.5 | 91.3% | 97.4% | |||
| BFS (8-mm-diameter) | Posterior | 5.64 ± 3.50 | 35.74 ± 25.95 | 12.5 | 87.3% | 96.1% | |||
| at thinnest point | Posterior elevation at thinnest point | 6.41 ± 3.83 | 47.39 ± 28.52 | 13.5 | 93.2% | 94.9% | |||
| Mostafa EM et al. [41] (Normal n = 500, KC n = 100) | Sirius | Elevation values at Thinnest corneal point | Spherical MAE | 5.2 ± 1.9 | - | 21.2 ± 11.3 | 24 | 91% | 92% |
| Aspherotoric MAE | 5.6 ± 2.4 | 23.9 ± 17.1 | 19 | 98% | 99% | ||||
| Spherical MPE | 6.3 ± 2.0 | 28.9 ± 18.1 | 15 | 92% | 93% | ||||
| Aspherotoric MPE | 6.7 ± 2.3 | 29.8 ± 17 | 12 | 98% | 99% | ||||
| Smadja D et al. [42] (Normal n = 177 FFKC n = 47 KC n = 167) | GALILEI | BFS and BFTA (8-mm-diameter) | BFS MAE | 5.4 ± 3.15 | 7.2 ± 4.3 | 25.2 ± 12.5 | 11 | 92% | 91% |
| BFTA MAE | 4.8 ± 1.7 | 8.4 ± 3.9 | 31.9 ± 15.8 | 9 | 98% | 99% | |||
| BFS MPE | 13.1 ± 5.2 | 15.4 ± 6.5 | 46.0 ± 20.6 | 21 | 93% | 95% | |||
| BFTA MPE | 8.6 ± 2.8 | 16.9 ± 6.9 | 57.8 ± 28.4 | 16 | 99% | 99% |
FFKC, Forme-Fruste Keratoconus; KC, keratoconus; BFS, best-fit sphere; BFTA, best-fit toric and aspherical surface; BFTE, best-fit toric-ellipsoid; MAE, mean anterior elevation; MPE, mean posterior elevation