Abstract
Purpose :
Trabeculectomy involves the placement of traction sutures and fixation of the conjunctival filtering bleb to the superior cornea, which could induce changes in corneal shape. The purpose of this work was to evaluate the refractive and aberrometric effect of trabeculectomy in glaucoma patients.
Methods :
Retrospective chart review of glaucoma patients who underwent fornix-based trabeculectomy between January and November 2015 at the Glaucoma Section of our hospital. Patients were evaluated with iTrace aberrometer (Tracey Technologies, Houston, TX) one week before and 3 months after surgery. Data is shown as mean±SD and statistical significance was set at p<0.05.
Results :
Data from 21 patients (11 female, 53±9 years) was analyzed. At the preoperative evaluation, mean spherical equivalent was -0.25±2.23 D, refractive cylinder was -1.68±0.94 D, refractive cylinder axis was 75±53°, average keratometry was 43.05±2.00 D, corneal astigmatism was 1.39±0.76D, steepest corneal meridian was 100±53°, refractive higher-order aberrations were 0.170±0.038 μm, coma was 0.102±0.029 μm and spherical aberration was 0.003±0.059 μm. A statistically significant change at 3 months after surgery was observed only in refractive cylinder axis (31±51°), steepest corneal meridian (-52±59°) and higher-order aberrations (0.150±0.138 μm).
Conclusions :
The trabeculectomy filtering bleb seems to exert a flattening effect on the superior cornea, leading to a shift in the astigmatism axis, but not in its magnitude, and an increase in higher-order aberrations. Such changes might contribute to the impaired visual quality that some patients refer after successful glaucoma surgery.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.