To compare pre and post macula thickness after single posterior sub-Tenon’s triamcinolone acetonide on progression of macular edema in diabetic patients and cystoids macula edema. The objectives were to compare the change in the central macular thickness (CMT) between macular edema in diabetic patients and cystoids macula edema. This was prospective study based on investigation; was performed on 44 eyes of treated between 2016 to 2017 for macular edema in diabetic patients and cystoids macula edema. In 44 eyes injected with 20 mg of TA, the mean central macular thickness was 530 +/- 103.73 µ SD before treatment. There was significant difference between before and after treatment the two groups (P=6.2, ANOVAs Single Factor). Follow up 15 days After Giving injection, it was 427.34 +/- 115.19 µ in injected eyes (Anova, single factor test) and after 30 days, the respective values were 339.79 +/- 126 µ (ANOVA Single Factor Test). I.e. statistically significant when difference between two follow up after giving treatment.