Table 3.
Dry eye and normal groups compared with respect to variability
| Dry eye | Normal | Ratio | P value | |
|---|---|---|---|---|
| Schirmer’s | 8.67 | 15.06 | 0.58 | 0.078 |
| Staining (all) | 0.56 | 0.33 | 1.67 | 0.005 |
| Staining (superior) | 0.58 | 0.37 | 1.59 | 0.010 |
| Staining (central) | 1.00 | 0.31 | 3.23 | <0.001 |
| Staining (inferior) | 0.65 | 0.48 | 1.35 | 0.092 |
| Forced-stare TFBUT | 0.34 | 0.63 | 0.54 | <0.001 |
| IBI | 1.11 | 0.53 | 2.09 | 0.001 |
| MBA (all) | 8.72 | 4.29 | 2.03 | 0.282 |
| MBA (central) | 8.45 | 3.10 | 2.73 | 0.094 |
| MBA (inferior) | 10.99 | 2.36 | 4.66 | 0.010 |
| MBA (superior) | 7.00 | 3.43 | 2.04 | 0.226 |
| OPI 2.0 (all) | 4.08 | 1.59 | 2.57 | 0.022 |
| OPI 2.0 (central) | 2.05 | 0.93 | 2.19 | 0.008 |
| OPI 2.0 (inferior) | 4.26 | 0.78 | 5.45 | <0.001 |
| OPI 2.0 (superior) | 1.76 | 1.18 | 1.50 | 0.172 |
Note: Ratios of standard deviation were used for Schirmer’s and staining, while ratios of coefficients of variation were used for forced-stare tear film breakup time, interblink interval, mean breakup area, and OPI 2.0.
Abbreviations: IBI, interblink interval; MBA, mean breakup area; OPI 2.0, mean breakup area/interblink interval; TFBUT, tear film breakup time.