Effect on untreated diabetic macular edema: posterior sub-tenon triamcinolone versus intravitreal bevacizumab

Aim: To compare the anatomical and visual effects of posterior sub-tenon triamcinolone (PSTT) and intra-vitreal bevacizumab (IVB) when used as the primary treatment for diabetic macular edema (DME). Methods: In a retrospective comparative study, 58 eyes of 47 patients which have received either PSTT or IVB were analyzed. Twenty-six eyes had received PSTT 40mg/1mL of preservative free Triamcinolone-acetonide (Group I) and 32 eyes had received intravitreal injection of 1.25mg/0.05 mL of avastin (Group II). Best corrected visual acuity (BCVA) and central macular thickness prior and six weeks post procedure were studied. Complications were studied. Results: In group I, BCVA increased from 31.04±9.89 letters to 41.08±6.77 letters with an increase of 10.04±9.34 letters (P<0.001). The mean central macular thickness (CMT) in group I changed from 571.42±125.71µ to 274.73±116.76µ with a decrease of 296.7±182.34µ (P<0.001). In group II BCVA increased from 35.03±8.39 letters to 54.44±10.56 letters by 19.41±12.51 letters (P<0.001) and mean CMT decreased from 618.91±143.76µ to 216.56±76.14 with a change of 402.34±155.91µ (P<0.001). IVB group had superior effect both on BCVA and CMT which was significant statistically too. P values for change in mean BCVA and change in CMT were 0.003 and 0.021. Two eyes in group I and 6 eyes in group II had subconjunctival hemorrhage. One eye in either group had raised intra ocular pressure (IOP) which was controlled medically. No major complications were noted in either group. Conclusions: In treatment of DME, both PSTT and IVB are effective in increasing the BCVA and decreasing the CMT. IVB is superior to PSTT. IVB is costly and may be associated with serious complications, as it’s an intraocular procedure. So PSTT can be tried as a first line of management in cases of untreated DME. Long term studies with multiple injections are required to know the long term effect and complications.