Table 1.
Key Previous Estimates of Corneal Back Surface Astigmatism
| Authors | Year | Instrument/Method | Values (D) |
|---|---|---|---|
| Dunne et al37 | 1992 | Purkinje Images | 0.23 (±0.02, n=40, F). |
| 0.37 (±0.03, n=40, M) | |||
| Oshika et al38 | 1998 | Scanning Slit Video | 0.18 (±0.16, n=50) |
| Liu et al39 | 1999 | Orbscan | 0.37 (±0.18, n=94) over 3.0mm |
| 0.52 (±0.25, n=94) over 5.0mm | |||
| 1.04 (±0.20, n=94) over 7.0mm | |||
| Dubbleman et al63 | 2006 | Scheimpflug imaging | 0.31 (n=114) |
| Kamiya et al64 | 2015 | Pentacam HR | 0.44 (±0.12, n=53) |
| Klijn et al22 | 2016 | Pentacam HR | 0.31 (±0.17,0.01 to 0.82, n=77) |
| Rydström et al40 | 2016 | Pentacam HR | 0.26 (±0.15, n=402) |
| Choi et al65 | 2018 | Scheimpflug imaging | 0.39 (±0.18, n=33) |
| Cui et al42 | 2019 | Cassini | 0.35 (0.04–0.89, n=117) |
| Pentacam HR | 0.29 (0.00–0.80, n=117) | ||
| Li et al43 | 2019 | Sirius | 0.31 (±0.17, 0.05–1.09, n=121) |
| Wylęgała et al48 | 2020 | Galilei G6 | 0.44 (n=94) over 4.0mm |
| Casia 2 | 0.52 (n=94) over 3.2mm | ||
| Revo NX | 0.05 (n=94) over 3.0mm |
Notes: All mean values for astigmatism have been converted into plus cylinder format where necessary; Values in parentheses are ±sd and ranges according to the corresponding publication (reference number is in superscript); Details of instruments, or methods, used by each group of investigators are noted as cited in the relevant publication.
Abbreviations: D, units of astigmatic power (dioptres); F, females; M, males.