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. Author manuscript; available in PMC: 2022 May 1.
Published in final edited form as: J Glaucoma. 2021 May 1;30(5):380–387. doi: 10.1097/IJG.0000000000001812

Table 3.

Power Calculations Based on Variable Recruitment Plans due to COVID-19 Delay

Scenario Recruitment Assumptions Screenings 80% Re-Screenings Standard Error, Margin of Error* Standard Deviation Difference Detected**
0 Hope: 5 NP/day for 3 years + 3 NP and 2 RS/day for 1 year
Hamilton: 5 NP/day for 2.5 years + 3 NP and 2 RS/day for 1 year		 7320 5856 1440 1.3, 2.6 0.073
1 Hope: 5 NP/day for 2 years + 3 NP and 2 RS/day for 1 year
Hamilton: 5 NP/day for 2 years + 3 NP and 2 RS/day for 1 year		 5760 4608 1440 1.5, 2.9 0.083
2 Hope: 4 NP/day for 3 years + 2 NP and 2 RS/day for 1 year
Hamilton: 4 NP/day for 2.5 years + 2 NP and 2 RS/day for 1 year		 6048 4838 960 1.4, 2.8 0.081
3 Hope: 5 NP/day for 1 years + 3 NP and 2 RS/day for 1 year
Hamilton: 5 NP/day for 2 years + 3 NP and 2 RS/day for 1 year		 5040 4032 1440 1.6, 3.1 0.088
4 Hope: 4 NP/day for 1 years + 2 NP and 2 RS/day for 1 year
Hamilton: 4 NP/day for 2 years + 2 NP and 2 RS/day for 1 year		 4224 3379 960 1.7, 3.4 0.096
*

Standard error, margin of error for disease prevalence estimate

**

standard deviation difference that a paired-sample t-test can detect with 80% power comparing re-screening visual acuity and vision-related quality of life to baseline values; NP, new patient; RS, re-screen patient