A prospective, longitudinal, observational cohort study examining how glaucoma affects quality of life and visually-related function over 4 years: design and methodology

Table 5 Sample confidence intervals for slopes of NEI-VFQ-25 and visual acuity

Number of subjects per class	Effective Sample Size N4.5/(1 + (4.5-1)0.2)	Distance from slope estimate to the two-sided 95 % confidence limits for the class-specific slope
Number of subjects per class	Effective Sample Size N4.5/(1 + (4.5-1)0.2)	NEI-VFQ (Std. Dev = 17)	LogMAR VA (Std. Dev = 0.2)
20	53	+/− 0.28	+/− 0.0033
60	159	+/− 0.16	+/− 0.0019
100	265	+/− 0.12	+/− 0.0014

ISSN: 1471-2415