We present the results of a consecutive series of graded transverse (T) incisions for correcting idiopathic astigmatism evaluated by vector analysis, a method not previously used to report T-incision results. In fact, no clinical studies on the results of the T-incision method have been reported. For comparison with conventional reporting methods, the results of graded T incisions on a series of eyes were evaluated, using both vector analysis and simplified analytic procedures. Sixty eyes were evaluated following surgery based on the Thornton guide for astigmatism correction. The mean preoperative cylinder in the series was 1.5 diopters (D) (SD = 0.43, range 1.00 D to 2.25 D); mean postoperative cylinder was 0.4 D (SD = 0.61, range 0 to 3.75 D). The mean decrease of 1.1 D was statistically significant. The results show that it is possible to quantify astigmatism correction using vector analysis.