Table 3

Change in visual acuity for the better and worse eye over time by group: comparison, adherent and non-adherent

	Unadjusted (worse eye) (95% CI)	Adjusted† (worse eye) (95% CI)	Unadjusted (better eye) (95% CI)	Adjusted† (better eye) (95% CI)
Constant	0.177 (0.159 to 0.194)*	0.386 (0.124 to 0.648)*	0.240 (0.026 to 0.454)*	0.240 (0.026 to 0.454)*
Age (months)	−0.009 (−0.011 to −0.008)***	−0.009 (−0.011 to −0.007)***	−0.006 (−0.008 to −0.005)***	−0.006 (−0.008 to −0.005)***
Age (months) squared	0.00016 (0.00012 to 0.00020)***	0.00016 (0.00012 to 0.00021)***	0.00010 (0.00007 to 0.00013)***	0.00010 (0.00006 to 0.00014)***
Group (reference: comparison)
Adherent	0.337 (0.309 to 0.366)***	0.337 (0.304 to 0.370)***	0.184 (0.162 to 0.106)***	0.170 (0.144 to 0.196)***
Non-adherent	0.277 (0.250 to 0.305)***	0.273 (0.241 to 0.305)***	0.150 (0.128 to 0.172)***	0.148 (0.123 to 0.174)***
Age × group interaction
Age × adherent	−0.008 (−0.009 to −0.007)***	−0.008 (−0.009 to −0.007)***	−0.004 (−0.005 to −0.004)***	−0.004 (−0.005 to −0.003)***
Age × non-adherent	−0.003 (−0.003 to −0.001)***	−0.003 (−0.004 to −0.001)***	−0.001 (−0.002 to 0.000)	−0.002 (−0.004 to 0.000)

× : interaction between group and age to determine if the effect of being in a particular group changes with age. The total effect for any one group is the coefficient for age plus the additional effect of age for that group.
*P<0.05, **P<0.01, ***P<0.001.
†Model adjusted for gender, ethnicity, gestation period, birth weight, birth route, maternal education status, maternal age and means-tested benefit status.