Der blev indenfor 7 dage efter behandlingen observeret alvorligt synstab, svarende til 4 linjer eller mere, hos 2, 1% af de verteporfinbehandlede patienter i de placebokontrollerede fase III afprøvninger og hos mindre end 1% af patienterne i ukontrollerede kliniske studier.
Severe vision decrease, equivalent to 4 lines or more, within seven days after treatment was reported in 2.1% of the verteporfin-treated patients in the placebo-controlled ocular Phase III clinical studies and in less than 1% of patients in uncontrolled clinical studies.