Purpose: To measure macular thickness using the Retinal Thickness Analyzer (RTA) (Talia Technologies, Ltd.) before and after routine phacoemulsification.
Setting: Ophthalmology Clinic, Ambulatory Care Center, University of North Carolina at Chapel Hill, School of Medicine, and the University of North Carolina Hospitals, Chapel Hill, North Carolina, USA.
Methods: Thirty-five nonconsecutive patients scheduled for phacoemulsification and posterior chamber intraocular lens implantation were recruited. The best corrected visual acuity (BCVA) and macular thickness in the surgical and nonsurgical eyes were measured with the RTA prior to surgery and 1 and 6 weeks after surgery. Wilcoxon signed rank tests were used to evaluate each index of macular thickness--the mean posterior pole, perifoveal, and foveal thicknesses--over the 3 time periods and to compare the indices before surgery in surgical and nonsurgical eyes. Spearman correlations were computed for each index and the BCVA. Significance was assessed at the 5% level.
Results: Preoperatively, all indices were higher in surgical [corrected] eyes than in nonsurgical [corrected] eyes. In surgical eyes, all indices decreased from preoperatively to 6 weeks after surgery. In nonsurgical eyes, there was no change. The BCVA in surgical eyes improved from before surgery to 1 week and 6 weeks after surgery. In surgical eyes, there were nonsignificant negative correlations between each index and the BCVA before surgery and 1 and 6 weeks after surgery. In nonsurgical eyes, there were nonsignificant negative correlations between each index and the BCVA preoperatively and 6 weeks after surgery, except for a significant negative correlation for the foveal index at 6 weeks.
Conclusions: Measurements by the RTA indicate that the decrease in macular thickness indices in surgical eyes from before surgery to 6 weeks after routine phacoemulsification is an artifact of imaging the retina through hazy media. Therefore, the results must be interpreted in the context of the clinical situation.