Table 2. National trends of the prevalence of cataract, glaucoma, and macular degeneration and β-coefficients of odds ratios before and during the COVID-19 pandemic, weighted % (95% CI), in the data obtained from the KNHANES

Year	Category	Pre-pandemic			During the pandemic		Trends in the pre-pandemic era, β (95% CI)	Trends in during the pandemic era, β (95% CI)	βdiff between pre-pandemic and during the pandemic (95% CI)
		2015-2016	2017-2018	2019	2020	2021
Overall	Cataract	3.27 (2.94 to 3.60)	3.77 (3.42 to 4.13)	3.21 (2.77 to 3.66)	3.19 (2.69 to 3.68)	3.22 (2.73 to 3.72)	-0.03 (-0.32 to 0.25)	0.01 (-0.34 to 0.35)	0.04 (-0.40 to 0.48)
	Glaucoma	0.70 (0.57 to 0.84)	0.92 (0.76 to 1.09)	0.80 (0.59 to 1.02)	0.90 (0.65 to 1.15)	1.15 (0.85 to 1.45)	0.05 (-0.08 to 0.18)	0.17 (-0.01 to 0.36)	0.12 (-0.10 to 0.35)
	Macular degenera-tion	0.21 (0.14 to 0.29)	0.38 (0.28 to 0.47)	0.59 (0.40 to 0.78)	0.64 (0.43 to 0.86)	0.45 (0.30 to 0.61)	0.19 (0.09 to 0.29)	-0.07 (-0.19 to 0.06)	-0.26 (-0.42 to -0.10)
Age
20-39 years	Cataract	0.29 (0.08 to 0.51)	0.30 (0.06 to 0.54)	0.21 (0.00 to 0.44)	N/A	0.05 (0.00 to 0.13)	-0.04 (-0.20 to 0.11)	-0.08 (-0.20 to 0.04)	-0.04 (-0.24 to 0.16)
	Glaucoma	0.19 (0.03 to 0.35)	0.16 (0.03 to 0.29)	0.15 (0.00 to 0.36)	0.04 (0.00 to 0.12)	N/A	-0.02 (-0.15 to 0.11)	-0.08 (-0.18 to 0.03)	-0.06 (-0.22 to 0.11)
	Macular degeneration	0.06 (0.00 to 0.15)	0.09 (0.00 to 0.20)	0.19 (0.00 to 0.45)	0.15 (0.00 to 0.43)	0.05 (0.00 to 0.14)	0.07 (-0.07 to 0.20)	-0.07 (-0.21 to 0.06)	-0.14 (-0.33 to 0.05)
40-59 years	Cataract	1.37 (0.90 to 1.84)	1.40 (1.00 to 1.80)	1.52 (1.00 to 2.05)	1.70 (1.01 to 2.39)	1.30 (0.78 to 1.83)	0.08 (-0.27 to 0.43)	-0.11 (-0.48 to 0.26)	-0.19 (-0.69 to 0.32)
	Glaucoma	0.43 (0.22 to 0.65)	0.74 (0.46 to 1.02)	0.65 (0.27 to 1.02)	1.11 (0.49 to 1.74)	0.78 (0.33 to 1.22)	0.11 (-0.11 to 0.32)	0.07 (-0.23 to 0.36)	-0.04 (-0.40 to 0.32)
	Macular degeneration	0.05 (0.00 to 0.13)	0.08 (0.00 to 0.17)	0.16 (0.00 to 0.38)	0.12 (0.00 to 0.36)	0.04 (0.00 to 0.11)	0.06 (-0.06 to 0.17)	-0.06 (-0.18 to 0.05)	-0.12 (-0.28 to 0.04)
≥ 60 years	Cataract	14.20 (12.95 to 15.45)	15.41 (14.11 to 16.71)	11.93 (10.44 to 13.43)	11.16 (9.50 to 12.82)	11.22 (9.63 to 12.80)	-1.20 (-2.18 to -0.22)	-0.35 (-1.47 to 0.77)	0.85 (-0.64 to 2.34)
	Glaucoma	2.44 (1.92 to 2.95)	2.97 (2.39 to 3.56)	2.48 (1.76 to 3.19)	2.11 (1.44 to 2.78)	3.68 (2.69 to 4.68)	0.01 (-0.44 to 0.45)	0.62 (0.00 to 1.25)	0.62 (-0.15 to 1.38)
	Macular degeneration	0.62 (0.34 to 0.89)	1.16 (0.82 to 1.50)	1.61 (0.94 to 2.28)	1.54 (0.95 to 2.12)	1.49 (0.94 to 2.05)	0.50 (0.13 to 0.87)	-0.06 (-0.50 to 0.38)	-0.56 (-1.13 to 0.02)
Sex
Male	Cataract	2.10 (1.73 to 2.47)	2.46 (2.10 to 2.82)	2.30 (1.80 to 2.79)	2.24 (1.74 to 2.74)	2.36 (1.78 to 2.94)	0.10 (-0.21 to 0.41)	0.03 (-0.35 to 0.42)	-0.06 (-0.56 to 0.43)
	Glaucoma	0.67 (0.48 to 0.86)	1.01 (0.76 to 1.25)	0.83 (0.52 to 1.14)	0.97 (0.61 to 1.33)	1.05 (0.65 to 1.45)	0.08 (-0.10 to 0.26)	0.11 (-0.14 to 0.37)	0.03 (-0.28 to 0.35)
	Macular degeneration	0.24 (0.12 to 0.36)	0.36 (0.22 to 0.51)	0.47 (0.25 to 0.69)	0.71 (0.37 to 1.06)	0.38 (0.19 to 0.56)	0.12 (-0.01 to 0.24)	-0.05 (-0.19 to 0.10)	-0.16 (-0.36 to 0.03)
Female	Cataract	4.45 (3.93 to 4.96)	5.09 (4.52 to 5.66)	4.13 (3.42 to 4.84)	4.13 (3.39 to 4.88)	1.25 (0.81 to 1.68)	-0.16 (-0.60 to 0.28)	-0.02 (-0.55 to 0.51)	0.14 (-0.55 to 0.83)
	Glaucoma	0.74 (0.54 to 0.93)	0.84 (0.61 to 1.07)	0.78 (0.49 to 1.07)	0.83 (0.50 to 1.17)	0.53 (0.30 to 0.76)	0.02 (-0.15 to 0.19)	0.23 (-0.02 to 0.49)	0.21 (-0.10 to 0.52)
	Macular degeneration	0.18 (0.09 to 0.27)	0.39 (0.25 to 0.52)	0.71 (0.39 to 1.02)	0.57 (0.29 to 0.85)	3.68 (2.85 to 4.51)	0.26 (0.10 to 0.43)	-0.09 (-0.28 to 0.11)	-0.35 (-0.61 to -0.09)
Region of residence
Urban	Cataract	3.02 (2.60 to 3.44)	3.95 (3.41 to 4.49)	3.61 (2.91 to 4.32)	3.67 (2.86 to 4.49)	3.68 (2.85 to 4.51)	0.32 (-0.09 to 0.73)	0.03 (-0.51 to 0.58)	-0.29 (-0.97 to 0.40)
	Glaucoma	0.54 (0.40 to 0.68)	1.10 (0.83 to 1.37)	1.05 (0.66 to 1.45)	0.92 (0.54 to 1.29)	1.11 (0.61 to 1.61)	0.27 (0.06 to 0.47)	0.03 (-0.28 to 0.34)	-0.24 (-0.61 to 0.14)
	Macular degeneration	0.22 (0.11 to 0.33)	0.41 (0.26 to 0.56)	0.67 (0.36 to 0.99)	0.78 (0.40 to 1.16)	0.36 (0.14 to 0.58)	0.22 (0.06 to 0.39)	-0.16 (-0.35 to 0.04)	-0.38 (-0.63 to -0.13)
Rural	Cataract	3.63 (3.10 to 4.17)	3.62 (3.13 to 4.11)	2.88 (2.29 to 3.48)	2.79 (2.18 to 3.40)	2.84 (2.26 to 3.43)	-0.39 (-0.80 to 0.02)	-0.02 (-0.44 to 0.40)	0.37 (-0.21 to 0.96)
	Glaucoma	0.93 (0.66 to 1.20)	0.77 (0.56 to 0.97)	0.60 (0.37 to 0.84)	0.89 (0.55 to 1.23)	1.18 (0.82 to 1.54)	-0.17 (-0.34 to 0.01)	0.29 (0.08 to 0.50)	0.46 (0.18 to 0.73)
	Macular degeneration	0.20 (0.10 to 0.29)	0.34 (0.21 to 0.48)	0.52 (0.29 to 0.75)	0.53 (0.29 to 0.78)	0.53 (0.31 to 0.75)	0.16 (0.03 to 0.29)	0.00 (-0.16 to 0.16)	-0.16 (-0.36 to 0.05)
Educational background
High school or lower	Cataract	6.08 (5.49 to 6.66)	6.92 (6.24 to 7.60)	6.00 (5.16 to 6.84)	6.15 (5.06 to 7.24)	5.51 (4.69 to 6.32)	-0.03 (-0.55 to 0.48)	-0.25 (-0.85 to 0.35)	-0.21 (-1.00 to 0.57)
	Glaucoma	1.15 (0.91 to 1.39)	1.49 (1.17 to 1.80)	1.38 (0.96 to 1.80)	1.51 (1.01 to 2.00)	1.86 (1.38 to 2.35)	0.12 (-0.12 to 0.36)	0.24 (-0.07 to 0.56)	0.13 (-0.27 to 0.52)
	Macular degeneration	0.37 (0.22 to 0.52)	0.62 (0.43 to 0.81)	0.92 (0.53 to 1.31)	1.02 (0.62 to 1.42)	0.82 (0.50 to 1.14)	0.28 (0.07 to 0.48)	-0.05 (-0.30 to 0.20)	-0.33 (-0.65 to 0.00)
College or higher	Cataract	1.21 (0.86 to 1.55)	1.64 (1.30 to 1.98)	1.41 (1.01 to 1.81)	1.29 (0.89 to 1.70)	1.93 (1.36 to 2.50)	0.09 (-0.17 to 0.36)	0.26 (-0.09 to 0.61)	0.17 (-0.27 to 0.61)
	Glaucoma	0.45 (0.26 to 0.64)	0.58 (0.38 to 0.79)	0.49 (0.24 to 0.74)	0.65 (0.31 to 0.99)	0.78 (0.33 to 1.24)	0.02 (-0.14 to 0.17)	0.15 (-0.12 to 0.41)	0.13 (-0.18 to 0.43)
	Macular degeneration	0.11 (0.03 to 0.19)	0.24 (0.13 to 0.36)	0.43 (0.20 to 0.66)	0.51 (0.20 to 0.82)	0.21 (0.05 to 0.37)	0.16 (0.04 to 0.28)	-0.11 (-0.25 to 0.03)	-0.27 (-0.46 to -0.08)
Economic level of family
Low	Cataract	5.78 (5.12 to 6.44)	6.51 (5.84 to 7.19)	5.28 (4.43 to 6.13)	4.84 (4.01 to 5.67)	5.02 (4.09 to 5.95)	-0.26 (-0.81 to 0.29)	-0.13 (-0.78 to 0.51)	0.13 (-0.72 to 0.97)
	Glaucoma	1.01 (0.76 to 1.26)	1.44 (1.11 to 1.78)	1.15 (0.76 to 1.54)	1.02 (0.63 to 1.40)	1.91 (1.34 to 2.47)	0.07 (-0.16 to 0.30)	0.37 (0.03 to 0.71)	0.30 (-0.10 to 0.71)
	Macular degeneration	0.25 (0.13 to 0.36)	0.47 (0.31 to 0.64)	0.81 (0.47 to 1.14)	0.75 (0.39 to 1.11)	0.82 (0.47 to 1.16)	0.28 (0.10 to 0.46)	0.00 (-0.24 to 0.24)	-0.28 (-0.57 to 0.02)
High	Cataract	1.64 (1.34 to 1.94)	1.99 (1.70 to 2.28)	1.78 (1.35 to 2.21)	2.21 (1.68 to 2.75)	2.16 (1.67 to 2.65)	0.07 (-0.20 to 0.33)	0.19 (-0.14 to 0.52)	0.12 (-0.30 to 0.54)
	Glaucoma	0.51 (0.34 to 0.67)	0.58 (0.42 to 0.75)	0.57 (0.34 to 0.80)	0.83 (0.49 to 1.18)	0.70 (0.31 to 1.09)	0.03 (-0.11 to 0.17)	0.07 (-0.16 to 0.29)	0.04 (-0.23 to 0.30)
	Macular degeneration	0.19 (0.10 to 0.28)	0.31 (0.19 to 0.43)	0.44 (0.22 to 0.65)	0.58 (0.31 to 0.85)	0.24 (0.09 to 0.38)	0.12 (0.01 to 0.24)	-0.10 (-0.23 to 0.03)	-0.23 (-0.40 to -0.05)
BMI groupa
Underweight to normal	Cataract	2.23 (1.88 to 2.58)	2.93 (2.55 to 3.32)	2.34 (1.84 to 2.84)	2.55 (1.90 to 3.20)	2.48 (1.86 to 3.11)	0.05 (-0.26 to 0.36)	0.07 (-0.33 to 0.47)	0.02 (-0.49 to 0.52)
	Glaucoma	0.60 (0.43 to 0.77)	0.77 (0.55 to 1.00)	0.63 (0.37 to 0.88)	0.77 (0.43 to 1.10)	1.06 (0.66 to 1.47)	0.01 (-0.14 to 0.16)	0.22 (-0.02 to 0.46)	0.21 (-0.08 to 0.49)
	Macular degeneration	0.18 (0.08 to 0.28)	0.23 (0.14 to 0.33)	0.56 (0.30 to 0.83)	0.62 (0.31 to 0.93)	0.31 (0.12 to 0.51)	0.19 (0.05 to 0.33)	-0.12 (-0.29 to 0.04)	-0.31 (-0.53 to -0.10)
Over-weight to obese	Cataract	4.31 (3.78 to 4.83)	4.60 (4.09 to 5.10)	4.06 (3.35 to 4.76)	3.60 (2.98 to 4.22)	3.82 (3.12 to 4.52)	-0.13 (-0.57 to 0.32)	-0.12 (-0.63 to 0.40)	0.01 (-0.67 to 0.69)
	Glaucoma	0.81 (0.58 to 1.04)	1.07 (0.84 to 1.31)	0.99 (0.64 to 1.33)	1.02 (0.67 to 1.37)	1.22 (0.80 to 1.64)	0.09 (-0.12 to 0.30)	0.12 (-0.15 to 0.39)	0.03 (-0.31 to 0.37)
	Macular degeneration	0.24 (0.14 to 0.35)	0.52 (0.35 to 0.69)	0.62 (0.36 to 0.88)	0.65 (0.35 to 0.95)	0.50 (0.27 to 0.72)	0.19 (0.05 to 0.33)	-0.06 (-0.23 to 0.11)	-0.25 (-0.47 to -0.03)
Smoking status
Smoker	Cataract	2.24 (1.43 to 3.05)	1.62 (1.16 to 2.08)	2.21 (1.37 to 3.05)	2.03 (1.10 to 2.96)	1.51 (0.74 to 2.28)	-0.02 (-0.60 to 0.57)	-0.35 (-0.92 to 0.23)	-0.33 (-1.15 to 0.49)
	Glaucoma	0.77 (0.41 to 1.14)	0.82 (0.44 to 1.20)	0.91 (0.34 to 1.49)	1.00 (0.31 to 1.70)	1.16 (0.20 to 2.12)	0.07 (-0.27 to 0.41)	0.13 (-0.43 to 0.68)	0.06 (-0.59 to 0.70)
	Macular degeneration	0.29 (0.05 to 0.53)	0.27 (0.03 to 0.50)	0.32 (0.03 to 0.61)	0.37 (0.00 to 0.79)	0.25 (0.00 to 0.54)	0.01 (-0.17 to 0.20)	-0.03 (-0.24 to 0.17)	-0.05 (-0.33 to 0.23)
Ex-smoker	Cataract	3.80 (3.05 to 4.56)	4.31 (3.59 to 5.02)	4.05 (3.07 to 5.03)	3.72 (2.83 to 4.62)	4.41 (3.23 to 5.58)	0.12 (-0.51 to 0.74)	0.19 (-0.57 to 0.95)	0.07 (-0.91 to 1.05)
	Glaucoma	1.01 (0.64 to 1.37)	1.45 (0.97 to 1.93)	1.20 (0.63 to 1.77)	1.51 (0.76 to 2.25)	1.73 (0.95 to 2.50)	0.09 (-0.25 to 0.43)	0.26 (-0.22 to 0.75)	0.17 (-0.42 to 0.77)
	Macular degeneration	0.32 (0.11 to 0.54)	0.79 (0.44 to 1.14)	0.85 (0.35 to 1.36)	1.33 (0.57 to 2.10)	0.47 (0.16 to 0.78)	0.26 (-0.02 to 0.54)	-0.20 (-0.50 to 0.10)	-0.46 (-0.87 to -0.05)
Non-smoker	Cataract	3.42 (3.04 to 3.79)	4.21 (3.74 to 4.68)	3.22 (2.65 to 3.80)	3.31 (2.73 to 3.90)	3.25 (2.61 to 3.90)	-0.10 (-0.45 to 0.25)	0.01 (-0.43 to 0.46)	0.11 (-0.45 to 0.67)
	Glaucoma	0.61 (0.45 to 0.77)	0.80 (0.61 to 0.99)	0.66 (0.43 to 0.89)	0.69 (0.42 to 0.96)	0.95 (0.62 to 1.29)	0.03 (-0.11 to 0.17)	0.15 (-0.05 to 0.35)	0.12 (-0.12 to 0.36)
	Macular degeneration	0.16 (0.09 to 0.24)	0.29 (0.19 to 0.39)	0.58 (0.32 to 0.84)	0.50 (0.28 to 0.72)	0.50 (0.29 to 0.70)	0.21 (0.08 to 0.34)	-0.04 (-0.21 to 0.12)	-0.25 (-0.46 to -0.04)
Alcohol consumption
Non-drinker	Cataract	4.37 (3.86 to 4.87)	4.77 (4.21 to 5.34)	3.86 (3.20 to 4.53)	4.07 (3.38 to 4.75)	3.92 (3.19 to 4.64)	-0.26 (-0.68 to 0.17)	0.03 (-0.48 to 0.53)	0.28 (-0.38 to 0.94)
	Glaucoma	0.77 (0.58 to 0.95)	0.93 (0.71 to 1.15)	0.90 (0.61 to 1.20)	1.00 (0.66 to 1.34)	1.13 (0.73 to 1.53)	0.07 (-0.11 to 0.24)	0.12 (-0.13 to 0.36)	0.05 (-0.26 to 0.35)
	Macular degeneration	0.26 (0.15 to 0.36)	0.50 (0.33 to 0.66)	0.73 (0.42 to 1.04)	0.76 (0.44 to 1.08)	0.58 (0.36 to 0.81)	0.24 (0.07 to 0.40)	-0.08 (-0.27 to 0.12)	-0.31 (-0.56 to -0.06)
1–5 days/month	Cataract	2.00 (1.60 to 2.40)	2.66 (2.19 to 3.14)	2.44 (1.73 to 3.15)	1.99 (1.37 to 2.60)	2.31 (1.59 to 3.04)	0.22 (-0.19 to 0.63)	-0.07 (-0.57 to 0.44)	-0.28 (-0.93 to 0.36)
	Glaucoma	0.60 (0.37 to 0.84)	0.84 (0.55 to 1.13)	0.71 (0.32 to 1.10)	0.86 (0.27 to 1.44)	1.18 (0.65 to 1.71)	0.05 (-0.18 to 0.28)	0.24 (-0.09 to 0.57)	0.19 (-0.22 to 0.59)
	Macular degeneration	0.09 (0.01 to 0.17)	0.15 (0.03 to 0.27)	0.40 (0.08 to 0.73)	0.63 (0.27 to 0.99)	0.31 (0.06 to 0.56)	0.16 (-0.01 to 0.33)	-0.04 (-0.25 to 0.16)	-0.20 (-0.47 to 0.06)
6–30 days/month	Cataract	2.22 (1.57 to 2.87)	2.83 (2.18 to 3.48)	2.64 (1.85 to 3.43)	2.47 (1.54 to 3.40)	2.54 (1.62 to 3.45)	0.21 (-0.30 to 0.73)	-0.05 (-0.66 to 0.55)	-0.27 (-1.06 to 0.53)
	Glaucoma	0.68 (0.36 to 1.01)	1.02 (0.61 to 1.42)	0.68 (0.20 to 1.16)	0.68 (0.25 to 1.12)	1.14 (0.43 to 1.85)	0.00 (-0.29 to 0.29)	0.23 (-0.20 to 0.65)	0.23 (-0.29 to 0.74)
	Macular degeneration	0.28 (0.04 to 0.52)	0.39 (0.18 to 0.59)	0.48 (0.15 to 0.82)	0.32 (0.00 to 0.74)	0.26 (0.00 to 0.55)	0.10 (-0.10 to 0.31)	-0.11 (-0.33 to 0.11)	-0.21 (-0.51 to 0.09)

BMI, body mass index; CI, confidence interval; KNHANES, Korea National Health and Nutrition Examination Survey.
BMI is divided into two groups: underweight to normal (<23.0 kg/m²) or overweight to obese (≥ 23.0 kg/m²).
The numbers in bold indicate a significant difference (p<0.05).