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S.B. Patel; Measurement of Macular Thickness by RTA after Phacoemulsification . Invest. Ophthalmol. Vis. Sci. 2003;44(13):227.
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Purpose: Measurement of macular thickness by non-invasive imaging, Retinal Thickness Analyzer (RTA), after phacoemulsification. Methods: To evaluate macular thickness by RTA after uncomplicated phacoemulsification and pcIOL, a prospective clinical trial was completed on 6 of 17 patients with senile cataracts without eye disease except mild AMD. Patients had topical anesthesia, 3 mm temporal clear corneal incisions, and 3-piece acrylic injectable IOLs. Best corrected visual acuities (BCVA) were measured preoperatively and at 1 week and 6 weeks postoperatively. Macular thickness was evaluated by RTA at these time periods. Indices used to compare retinal thickness at each time interval included: (1) foveal average thickness (ft), (2) posterior pole average thickness (ppt), and (3) perifoveal average thickness (pft). Indices were compared across the time periods using the ANOVA. Results: These data are for the 6 patients who have completed the study. For the surgical eye, no significant changes were noted for ft, ppt, and pft over the time periods. The mean values of macular thickness in microns were: 175 (preop), 207 (1 week), 179 (6 weeks) for ft; 176, 192, 203 for ppt; and 179, 195, 203 for pft. For ft, sd increased from 23.6 preop, to 73.4 at 1 week and then decreased to 29.3 at 6 weeks postop. For ppt and pft, sd increased from 20.6 and 21.0 preop, to 53.4 and 52.0 at 1 week and remained stable at 51.1 and 47.1 at 6 weeks postop. For the non-surgical eye, no significant changes were noted for ft, ppt, and pft over the three time periods. The mean macular thickness values were: 155, 163, 188 for ft; 186, 165, 193 for ppt; and 184, 168, and 195 for pft. For ft, sd increased from 20.0 preop, to 34 at 1 week and to 72.7 at 6 weeks postop. For ppt and pft, sd decreased from 23.8 and 21.7 preop, to 15.7 and 15.5 at 1 week and increased to 57.1 and 57.0 at 6 weeks postop, respectively. Conclusions: Prior studies of uncomplicated phaco and pcIOL showed the incidence of clinically-apparent cystoid macular edema (CME) to be about 1%. Fluorescein angiographic CME was approximately 19%. Our study, using a non-invasive imaging technique, RTA, demonstrated no significant change in macular thickness over a time course from preop to 1 week to 6 weeks postop. When larger areas of the posterior pole were evaluated (ppt and pft), mean values increased from preop to 6 weeks postop suggesting that some degree of CME was present, but not clinically important based on BCVA. For the non-surgical eye, the increase in ft suggests that foveal thickening may occur as a contralateral phenomenon. After uncomplicated phaco and pcIOL, the RTA seems to be an effective way to detect subtle changes in macular thickness.
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