Table 1: Ocular surface diseases severity grading and pain score.
| 4 | Severe pain (awakening in the night due to pain) 6 times a year or more |
| 3 | Severe pain for less than 6 times a year or moderate pain (soreness early in the morning or during the day) for at least 6 times a year |
| 2 | Moderate pain for less than 6 times a year |
| 1 | No pain or foreign body sensation |