[1] St Anna Hosp, NICU, Turin, Italy
[2] Azienda Osped, Pediat Neonatal Intens Care Unit, Div Pediat, Verona, Italy
[3] City Hosp, Div Neonatol & Pediat, Thiene, Italy
[4] Referral Ctr ROP Piedmont, Turin, Italy
[5] Univ Turin, Dept Pediat, I-10124 Turin, Italy