Fig 1.
Regression analysis of age and near add power in 2017, 2019 and 2020–21.
The slope (rate of presbyopia progression) became flatter from 2017 to 2021, implicating presbyopia developed earlier and progressed slower toward the pandemic in 2020–21. Red triangle symbol and red solid regression line for 2017, black square symbol and black dotted regression line for 2019, and black circle symbol and black solid regression line for 2020–21. Note many plots are overlapped and small number appears in the graph.
Fig 2.
Scatter plots of near add power and age with a probability ellipse (confidence interval 95%) in 2017, 2019, and 2020–21.
Correlation between age and near add power became weaker toward the pandemic 2020–21. The standardized correlation coefficient between age and near add power was 0.816 for 2017, 0.671 for 2019 (P = 0.084, t test, vs 2017), and 0.572 for 2020–21 (P<0.001, vs 2017). Note many plots are overlapped and small number appears in the graph.
Table 1.
Refraction and presbyopia status.
Table 2.
Multiple regression analysis of near add power and possible confounding factors.
Table 3.
The prevalence of dry eye-related symptoms and corneal signs.