SURGICAL CONTROL OF LATE POSTKERATOPLASTY ASTIGMATISM WITH OR WITHOUTTHE USE OF COMPUTERIZED VIDEO KERATOGRAPHY - A PROSPECTIVE, RANDOMIZED STUDY

Objective: To assess the effectiveness of computerized videokeratograp hy (CVK) in refining the surgical design and in improving predictabili ty of surgical correction of postkeratoplasty astigmatism. Design: A p rospective, controlled, randomized, clinical trial. Participants: A to tal of 31 postkeratoplasty eyes, divided into 2 groups (group A, 16 ey es; group B, 15 eyes), with more than 4 diopters (D) of disabling asti gmatism were studied. Intervention: Ail eyes were treated with a combi nation of arcuate relaxing incisions and compression sutures, The surg ical plan in group A was based on topographic information, whereas in the control group B, the surgical plan was based on information obtain ed by refraction and keratometry alone. Main Outcome Measures: Change in the surgical plan induced by the CVK information, astigmatism, topo graphic patterns, and factors associated with outcome were measured. R esults: in all 16 cases of group A, the use of CVK changed some aspect of the surgical plan. At 12 months after surgery, both groups showed a significant net reduction (P = 0.001) of baseline astigmatism. Howev er, the reduction (47% and 41% for groups A and B, respectively) did n ot differ significantly between the two groups. The topographic astigm atism at 12 months measured 4.24 +/- 0.71 D in group A and 5.60 +/- 0. 51 D in group B (P = 0.139). Significant differences between the two g roups at 12 months were seen only for keratometric astigmatism (3.60 /- 0.81 D in group A vs. 5.77 +/- 0.52 D in group B, P = 0.035) and re fractive astigmatism (2.34 +/- 0.37 D in group A vs. 4.88 +/- 0.52 D i n group B, P = 0.000). The mean vector surgical effect was 91% for gro up A and 70% for group B. Regular astigmatism patterns had a greater b enefit from surgery than irregular patterns (P = 0.008). Previous refr active surgery was associated with less-favorable outcome (P = 0.045). Conclusions: The current study indicates that the use of CVK provides a benefit compared to keratometry and refraction alone in the plannin g and outcome of surgical treatment for high postgraft astigmatism.