Purpose: To evaluate the retention of intravitreal triamcinolone acetonide (TA) particles and the efficacy of TA therapy for patients with cystoid macular edema in branch retinal vein occlusion (BRVO) or diabetic macular edema (DME). We monitored the TA particles until absorption from the vitreous cavity was complete. The correlation between the intravitreal retention time of TA and its efficacy was evaluated based on central macular thickness (CMT).
Results: The intravitreal TA retention time was a mean 141.8 +/- 139.6 days in BRVO patients and 114.5 +/- 59.6 days in DME patients. Patient age and retention time were negatively correlated (r = -0.46; P = 0.013). At 6 months posttreatment the mean CMT decreased from 544.1 +/- 143.7 to 322.4 +/- 131.9 mum in BRVO patients and from 454.5 +/- 119.0 to 371.2 +/- 209.4 mum in DME patients. Retention time and CMT reduction were positively correlated in BRVO patient (r = 0.56, P = 0.02) but not in DME patients (P = 0.06).
Conclusions: Intravitreal TA reduced the CMT in BRVO and DME patients over 6 months. The retention time was longer in younger individuals. The efficacy of the therapy depended on the intravitreal TA retention time observed clinically in BRVO patients. Biomicroscopic examination of intravitreal TA is useful for evaluation of its efficacy.