VECTOR ANALYSIS OF CORNEAL ASTIGMATISM AFTER SCLERAL BUCKLING SURGERY

We conducted a short-term prospective study of 125 eyes with retinal detachment to examine changes of corneal astigmatism about 2 weeks after scleral buckling surgery, using a vector method on 2-fold-angle rectangular coordinates. Segmental buckles of one to less than two quadrants produced significantly greater changes in astigmatism (1.65+/-0.97 dptr) than those of less than one quadrant (0.88+/-0.75 dptr) and those spanning two quadrants or more (1.09+/-0.38 dptr) (p=0.0005, Kruskal-wallis test; n=73). The amplitude of differential vectors after explant buckling surgery (1.33+/-0.89 dptr, n=24) was significantly greater than after implant buckling surgery (0.65+/-0.45 dptr, n=15) (p=0.009, Mann-Whitney U-test) with buckles of one quadrant or less. Differential vectors tended to direct toward the buckles. There was no obvious directional tendency in the case of encircling procedures (n=52).