Table 4 Ocular symptoms and signs according to season.

Ocular surface disease index

36.7 ± 22.3

31.6 ± 19.4

35.4 ± 20.4

35.1 ± 21.5

0.51^a

Dry eye severity level

2.0 ± 0.4

2.1 ± 0.5

2.0 ± 0.5

2.0 ± 0.5

0.85^a

Dry eye severity level 1 (% within season)

8.5

10.2

10.2

10

–

Dry eye severity level 2 (% within season)

81.5

71.4

75.8

75.4

–

Dry eye severity level 3 (% within season)

9.5

18.4

14

14.7

–

Dry eye severity level 4 (% within season)

0.5

0

0

0

–

Tear film breakup time

5.0 ± 3.9

6.7 ± 10.1

5.6 ± 3.9

4.9 ± 3.9

0.34^a

Ocular protection index

2.1 ± 2.2

2.7 ± 2.6

2.0 ± 1.6

1.8 ± 1.7

0.06^a

Ocular surface staining

1.5 ± 2.0

1.6 ± 2.2

1.5 ± 2.0

1.7 ± 2.1

0.67^a

Schirmer I

16.1 ± 10.5

10.1 ± 7.5^b

15.8 ± 10.3

15.4 ± 10.3

0.002^a

Tear meniscus height (% < 0.2 mm)

11.9

16.0

29.2^d

8.7

< 0.001^c

Meibum expressibility

1.1 ± 0.9

0.7 ± 0.8

1.0 ± 0.9

1.0 ± 0.9

0.051^a

Intraocular pressure

13.9 ± 3.2

12.9 ± 2.4

13.1 ± 3.6

15.1 ± 3.7^e

< 0.001^a