Materials and methods: Total 37 diabetic patients with ED were included in this single-centred, open-label prospective study. The treatment was initiated with 5 mg tadalafi l hydrochloride daily for 3 months. Choroidal thickness, central macular thickness (CMT), and total macular volume (TMV) measurements were performed using spectral domain optical coherence tomography (SD-OCT). SD-OCT and visual acuity (VA) measurements were repeated during all visits. Fundus fl uorescein angiography (FFA) was also performed at baseline and at the 12th week.

Results: There was a statistically signifi cant increase in the choroidal thickness compared to that at baseline at all visits except at the fi rst visit (mean central foveal choroidal thickness, baseline; 248.7 ± 21.5, 1st day; 247.4 ± 23.2, 4th week; 275.9 ± 21.3, and 12th week; 275.1 ± 24.4, ?m, p < 0.001). There was no statistically signifi cant change in the mean VA (baseline; 0.21 ± 0.07, 12th week; 0.22 ± 0.06, logMar), mean CMT (baseline; 236.7 ± 32.4, 12th week; 234.8 ± 32.8, ?m), mean TMV (baseline; 9.88 ± 1.21, 12th week; 9.83 ± 1.26, mm3), and FFA compared to the baseline values (p > 0.05).

Conclusions: Choroidal thickness safely increases in response to systemic tadalafi l administration. The long-term use of systemic tadalafi l does not cause any adverse effects on the retina and the macula in diabetic patients with ED. Keywords : Choroidal thickness; Diabetes Mellitus; Macula; Tadalafil