To describe in detail occurrences of acute severe visual acuity decrease after photodynamic therapy (PDT) with verteporfin in the Treatment of Age-related macular degeneration with Photodynamic therapy (TAP) Investigation and the Verteporfin In Photodynamic therapy (VIP) Trial.

Observational case series.

Retrospective review of all cases that developed acute severe visual acuity decrease after treatment.

Of 15 acute severe visual acuity decrease events originally identified in 14 eyes of 14 patients, one event in one patient was judged unlikely to have been an acute severe visual acuity decrease event on retrospective review of these events in preparation of this report. Eleven events occurred after the first treatment. At follow-up, 10 improved by at least 1 line in visual acuity from the level noted at the time of the event. Of the nine patients returning for the month 24 examination, visual acuity decreased at least 3 lines from baseline in six, including at least 6 lines in four, and remained within 1 line in three. Associated abnormal morphology included three with a serous macular detachment and abnormal choroidal hypofluorescence, four with macular hemorrhage, three with a greenish subfoveal hemorrhage, and four with no abnormality. Events appeared to be more likely when patients had a visual acuity of 20/50 or better.

Acute severe visual acuity decrease after PDT with verteporfin was an uncommon event; the risk did not outweigh the benefits of therapy previously reported. When considering verteporfin therapy, patients should be warned of the possibility of this serious adverse event.