In the sequential analysis , peak light intensity increased gradually in the first 24 months after implantation and reached a plateau ( relative difference with respect to baseline [ % Dif ] : 61.4 % at 12 months , 115.0 % at 24 months , 110.7 % at 36 months ) , while the median intensity kept increasing at 36 months ( % Dif : 14.3 % at 12 months , 75.0 % at 24 months , 93.1 % at 36 months ) .