ABSTRACT
We inspected reliability of A-constant of AMO SI-30NB by comparing target diopter and actual postoperative refractive status. Group 1 comprised 191 eyes which were implanted AMO PhacoFlex SI-30NB with corneal incision. Group 2 comprised 45 eyes implanted Pharmacia 812C with scleral incisions. Group 3 comprised 17 eyes implanted AMO OgaciFlex SI-30NB with corneal incision. Refraction was performed on post operative day 1, day 5, day 14, 1 month, and 3 month. It revealed hyperopic shift of 0.31 to 0.40 diopter compared to the target diopters in both Group 1 and Group 3 and no statistical difference was found between two groups(p value>0.05). On the other hand, Group 2 were statistically significant(p value<0.01). We attempted mathematical modelling of this phenomenon and the cause of hyperopylene haptics, structural weakness of haptic-optic junction, and the structure of SI-30NB itself.