Table 1.
Baseline demographic and clinical features of the study participants.
| Characteristics | All Participants | No Cataract Surgery | Postcataract Surgeries | P Value † |
|---|---|---|---|---|
| Participant, n (%) | 1397 | 1225 | 172 | |
| Mean age in years (SD) | 66.6 (9.7) | 65.4 (9.1) | 75.4 (9.0) | <0.001 |
| Sex, n (%) | 0.12 | |||
| Men | 531 (38.0) | 475 (38.8) | 56 (32.6) | |
| Women | 866 (62.0) | 750 (61.2) | 116 (67.4) | |
| Eye drop users for dry eye symptoms, n (%) | 411 (29.4) | 359 (29.3) | 52 (30.2) | 0.80 |
| Subjective symptoms | ||||
| Dry sensation, n (%) | 336 (24.1) | 302 (24.7) | 34 (19.8) | 0.16 |
| Foreign-body sensation, n (%) | 263 (18.8) | 226 (18.5) | 37 (21.5) | 0.34 |
| Ocular pain, n (%) | 84 (6.0) | 75 (6.1) | 9 (5.2) | 0.65 |
| Ocular fatigue, n (%) | 445 (31.9) | 396 (32.3) | 49 (28.5) | 0.31 |
| Sensitivity to bright light, n (%) | 238 (17.0) | 217 (17.7) | 21 (12.2) | 0.07 |
| Blurred vision, n (%) | 258 (18.5) | 227 (18.5) | 31 (18.0) | 0.87 |
| Clinical features | ||||
| Tear break-up time, seconds (SD) | 4.6 (1.8) | 4.7 (1.8) | 4.3 (1.9) | 0.02 |
| Keratoconjunctival staining score ‡, (SD) | 0.31 (0.6) | 0.29 (0.6) | 0.44 (0.7) | 0.008 |
| Maximum blinking interval, sec (SD) | 12.0 (5.8) | 12.1 (6.0) | 10.9 (4.4) | 0.002 |
| Abnormal ocular surface parameters * | ||||
| Short tear break-up time, n (%) | 172 (12.3) | 75 (11.0) | 97 (13.6) | 0.13 |
| Corneal epitheliopathy, n (%) | 172 (12.3) | 117 (11.0) | 55 (16.5) | 0.008 |
| Short maximum blinking interval, n (%) | 172 (12.3) | 107 (11.2) | 65 (14.9) | 0.05 |
† The tests for significance were t-tests for continuous variables and Chi-square tests for categorical variables. ‡ Keratoconjunctival staining scores, which originally ranged from 0 (minimum) to 9 (maximum) points by the Japan Dry Eye Association, were categorized into 3 groups: “mild” for 0–2 points, “moderate” for 3 points, and “severe” for 4+ points. We then rescored patients with “mild”, “moderate”, and “severe” as 0, 1, and 2 points, respectively. * Abnormal ocular surface parameters were defined as follows: tear break-up time ≤5 s, the presence of corneal epitheliopathy (keratoconjunctival staining score ≥3 points according to the Japanese dry eye criteria), and maximum blinking interval <10 s. Abbreviations: SD, standard deviation.