The Effect of Trabeculectomy on Ocular Pulse Amplitude

Abstract

PURPOSE. To investigate whether trabeculectomy, besides its intraocular pressure (IOP)-lowering effect, has an effect on ocular pulse amplitude (OPA); and to determine whether OPA changes are influenced by IOP changes. METHODS. Forty-eight patients with glaucoma (48 eyes) scheduled for unilateral first-time trabeculectomy were prospectively enrolled from October 2007 to April 2008. The eye undergoing trabeculectomy was considered the study eye, whereas the nonsurgical fellow eye was used as the control eye. OPA, IOP, blood pressure, and heart rate were measured before and 4 weeks after trabeculectomy by means of Pascal dynamic contour tonometry (DCT), Goldmann applanation tonometry (GAT), and sphygmomanometry. A regression model for repeated measures was used. RESULTS. Preoperative GAT, DCT, and OPA were 20.92 +/- 8.55, 21.33 +/- 7.06, and 3.23 +/- 1.58 mm Hg, respectively. One month after trabeculectomy, GAT, DCT, and OPA were 11.23 +/- 5.03, 14.45 +/- 4.79, and 2.12 +/- 1.07 mm Hg, respectively. There was a significant decrease in OPA after filtration surgery in the study eye compared with the control eye (P < 0.0001). Changes in OPA were correlated with changes in IOP (Spearman rho = 0.49, P = 0.0004). When the IOP change caused by filtration surgery was taken into account, no significant difference in effect on OPA after trabeculectomy was demonstrated in the study eye compared with the control eye (P = 0.18). CONCLUSIONS. OPA changes correlated strongly with IOP changes. There was no evidence of an effect of filtration surgery on OPA when the concomitant IOP decrease after trabeculectomy was taken into account. (Invest Ophthalmol Vis Sci. 2010; 51:231-235) DOI:10.1167/iovs.09-3712