Chapter 6: The Basics of the Alpins Method

Golf analogy, Alpins Method target induced astigmatism vector (TIA), surgically induced astigmatism vector (SIA), difference vector (DV) Now the Alpins Method has been adopted by the major Ophthalmology Journals, including JCRS, JRS and Ophthalmology. Let’s discuss the Alpins’ Method and what it actually involves. Well the fundamentals of the Alpins’ Method involves the relationship between 3 basic vectors. The TIA is the Target induced astigmatism vector which is actually the astigmatic treatment, what you put into the laser or what you put in to your nomogram for limbal relaxing incisions. Or even the power of the Toric implant at the corneal plane. The SIA is the change that you have measured from pre-op to post-op astigmatism, the Surgically induced astigmatism vector And then the third is what we call the Difference vector or DV and that is an interesting one because it is actually a very objective means of measuring how successful the surgery has been. It is how much you have missed the astigmatic target by and if you have corrected all the targeted astigmatism then the DV will be zero