The safety and tolerability of single intravitreal injections of ranibizumab was evaluated in patients enrolled in the single dose phase (Group A). Patients who successfully completed the single dose phase (i.e. did not experience a grade-3 targeted adverse event) could enter the multiple dose phase and receive ranibizumab injections for an additional 11 months. Simultaneously, the multiple dose phase was initiated in two parallel dose groups of additional patients (Group B), who received ranibizumab injections for 12 months. After patients in Group A and Group B had completed the multiple dose phase, all patients who provided written consent and were considered eligible based on the inclusion and exclusion criteria of the extension phase had the opportunity to continue on study treatment with the individualized flexible treatment regimen guided by monthly acuity scores and other ophthalmic examinations until approval of ranibizumab in Japan.