ASSORT -free Version Online Astigmatism and much more- Calculations from Noel Alpins MD

ORAOcular Residual Asigmatism- was introduced in 1997 from Noel Alpins MD to emphasize the frequent disparity of Topography to Refractive Astigmatic Vector. (20 years later is again the hot talk of the town) . Another Marker is TD (Topography Disparity), TIA (Target Induced Astigmatism) Vector, SIA (Surgical Induced Astigmatism) Vector and DV Difference Vector The ASSORT Software (10.000$ worth) is now “free” to be used by all registered users for single cases and single markers. You can calculate the ORA , Vector Planning, and Coupling Effect of LRI’s/ Excimer Laser Cases (Mixed Astigmatism).

Also Available there is an Excellent Toric IOL Calculator incorporating  different posterior Cornea Assumptions and a Version of Astigmatismfix.com to deal with the unhappy Toric IOL postop Result. 

http://www.assort.com/