OBJECTIVE To compare subtenon triamcinolone versus systemic dexamethasone for perisurgical management of primary rhegmatogenous retinal detachment presenting with a choroidal detachment (RRD/CD). METHODS Thirty consecutive primary RRD/CD patients were prospectively studied. Sixteen RRD/CD patients were injected with a 40 mg subtenon triamcinolone acetonide (TA) 5 days before a scheduled vitrectomy (TA group) while the other 14 RRD/CD patients were intravenously infused daily with 10 mg dexamethasone (Dex) for 5 days before a scheduled vitrectomy (Dex group). All patients were followed up for 6 months. Changes of choroid detachment on B ultrasonography and preoperative intraocular pressure (IOP), systemic and ocular steroid level, blood sugar, and postoperative macular oedema were compared between the two groups. RESULTS During 5 days of presurgical treatment, the IOP recovery from the baseline was 3.29 ± 4.56 mmHg for the TA group versus 1.16 ± 1.60 mmHg for the Dex group (p = 0.021). The height of CD decreased significantly more for the TA group (3.55 ± 1.33 versus 1.84 ± 1.5 mm, p = 0.0029). The physiological cortisol level in the plasma was significantly suppressed for the Dex group (8.35 ± 10.35 versus 51.9 ± 35.9 ng/ml, p = 0.01). Postoperative 1-month macula was less oedematous for TA group (401 ± 196 versus 256 ± 66 μm, p = 0.0498). CONCLUSIONS Subtenon TA seems to be a better option for perisurgical management of RRD/CD patients than systemic steroid application. Subtenon TA is more convenient for patients and imposes much less stress to patients' hormones homeostasis. This is especially important for those who are suffering metabolic disorders and need vitrectomy surgery for repairing RRD/CD.