Macular thickness after uneventful cataract surgery determined by optical coherence tomography

Abstract

Background: Using standardized macular optical coherence tomography (OCT) in the postoperative period, subclinical changes in macular thickness can be detected. With this method, postoperative development of macular thickness in healthy eyes is evaluated. The repeatability of the method and the influence of selected surgical (phaco time and phaco energy) and biometric parameters (axial length and anterior chamber depth) on the results were assessed.

Methods: In a prospective study, 33 patients without macular pathology in both eyes were examined. Phacoemulsification and intraocular lens (IOL) implantation was performed in one eye, and the contralateral eye served as control. OCT (StratusOCT; Zeiss, Dublin, CA, USA), mean minimal foveal thickness (MMFT) and mean foveal thickness (MFT) were measured preoperatively, at 1 day, 1 week and 6 weeks postoperatively. At these visits, the best-corrected visual acuity (BCVA) tests and slit-lamp examination were performed. To assess the influence on foveal thickness ocular axial length, anterior chamber depth, phacotime and energy were documented. Statistical analysis using parametric tests was carried out with standard statistical software (SPSS11, BIAS).

Results: MMFT of the operated eyes and the intraindividual difference of MMFT increased significantly at one day (+12.31 +/- 24.2 microm, P < 0.001) and 6 weeks (+6.76 +/- 22.6 microm, P = 0.009). MFT in the operated eyes and intraindividual difference of MFT rose significantly at 1 day, 1 week and 6 weeks (1 day: +10.66 +/- 20.8 microm, P = 0,026; 1 week: +15.23 +/- 19.7 microm; 6 weeks: +17.33 +/- 14.81 microm, P < 0.001). Repeatability was better for MFT in controls (ICR = 0.92) than for MMFT in controls (ICR = 0.77). No clinical cystoid macular edema was diagnosed in this study. No correlation between macular thickening and visual acuity and selected surgical and biometrical parameters could be found.

Conclusions: After cataract surgery, a mild increase of foveal thickness without impact on visual acuity could be observed. This increase may be due to both subclinical changes and to influence of changes in media opacity on the measurement technique. Surgical and biometric parameters such as phacotime and energy and axial length did not correlate to the degree of macular thickening.