[1] Univ Turin, Dept Internal Med, Diabet Retinopathy Ctr, I-10126 Turin, Italy
[2] Maria Vittoria Hosp, Dept Endocrinol & Diabet, Turin, Italy
[3] Maria Vittoria Hosp, Dept Opthalmol, Turin, Italy
[4] E Agnelli Hosp, Diabet Unit, Turin, Italy
[5] E Agnelli Hosp, Dept Ophthalmol, Turin, Italy
[6] Univ Turin, Dept Econ, Turin, Italy