We compared targeted contact lens power for distance with three other treatment techniques : ( 1 ) 30 D contact lens ( 32 D minus 2 D overcorrection for near vision based on IATS protocol ) ; ( 2 ) regression-estimated contact lens power of 84.4 - 3.2 axial length ; and ( 3 ) IOL power calculated using the Sanders-Retzlaff-Kraff ( SRK/T ) regression formula with a modified A-constant ( 112.176 ) .