AIM: To investigate the effects of exogenous testosterone treatment on the choroidal parameters in patients with androgen deficiency. METHODS: Right eyes of 24 patients with androgen deficiency and 31 healthy volunteers were included in the study. The eyes were scanned for subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), choroidstromal area (C-SA), choroid-luminal area (C-LA), choroidstromal to luminal area ratio (CSLR), and the choroidal parameters within central 1500 mu m of the macula (CVI1500, 1500 , C-LA1500, 1500 , C-SA1500, 1500 , and CSLR1500) 1500 ) by enhanced-depth imaging optical coherence tomography (EDI-OCT) at baseline, 6 th and 18th th weeks of the exogenous testosterone treatment. RESULTS: The mean SFCT values of the androgen deficient groups and healthy controls were 307.7 +/- 27.0 and 303.2 +/- 37.2 mu m (P=0.8). P =0.8). However, CVI, C-SA, CSLR, CVI1500, 1500 , C-LA1500,and- LA 1500, and CSLR1500were 1500 were significantly different between the groups (all P <0.01). At the 6 th week visit after exogenous testosterone treatment, SFCT, CVI, C-LA, and C-SA were significantly decreased, and these parameters returned to baseline levels at the 18th th-week visit (all P >0.05). However, CVI 1500 and LA 1500 significantly increased at the end of the follow-up period (P<0.001). P <0.001). CONCLUSION: CVI is lower in androgen-deficient patients than in healthy subjects. The alterations in the choroid during the testosterone peak are transient in the treatment of patients with androgen deficiency. However, the increase in CVI within the central 1500 mu m of the macula persists even after 4mo.