Chief & Presenting Author: Dr.Narendra Singh Verma

Abstract

Present SIA Calculator are based on vector method can measure magnitude (mean SIA & Centroid SIA) only. But can't measure rotation of steep axis which is also equally important to determine toric lens axis of alignment. New SIA calculator based on polar method can measure both component of SIA.
Two groups are compared by using both calculators.
Group 1- 57 cases of 2.8 mm phaco incision & 2.8 mm OCCI on steep axis.
Group 2- 12 cases of 2.8 mm temporal phaco incision not on steep axis.
SIA is calculate by using both calculators.
Vector method provides only magnitude of centroid SIA.
Polar method provides us magnitude components of SIA as well as SIA component for rotation of steep axis.
In Group 1 change in magnitude is more & in Group 2 rotation of steep axis is maximum.
When incision are on steep or flat axis change in cylindrical power is maximum but when incision are not on steep or flat axis rotation of steep axis is maximum.