Among eyes treated as needed ( n = 598 ) and followed up for 2 years ( n = 516 ) , the mean number of injections was 15.4 0.9 for eyes having VMT at baseline or during follow-up ( n = 60 ) , 13.8 0.7 for eyes with VMA at baseline or follow-up ( n = 79 ) , and 12.9 0.4 ( P = 0.02 ) for eyes without VMT or VMA ( n = 377 ) .