Background: Although intravenous fluorescein angiography (IVFA) is a relatively safe procedure, side effects have been shown to occur. The designed purpose of this study was to demonstrate a reduction in the frequency and severity of side effects during digital IVFA using 2 mL compared with 5 mL of 10% sodium fluorescein (NaFl). The secondary hypothesis was to show that no loss of image quality occurred with a reduction in the NaFl dose utilizing digital fluorescein angiography.
Methods: A prospective study was initiated in which 1200 patients were randomized to 2 mL or 5 mL of 10% NaFl to allow for the evaluation of adverse events. Standard IVFA technique utilizing modern high-resolution digital photography was employed. Photographers evaluated the difficulty of image capture. A masked observer recorded all adverse events. Masked ophthalmologists evaluated image quality subjectively with a 4-point rating scale. Secondary to concerns regarding image quality, a masked interim analysis was carried out after 140 patients had been randomized.
Results: A statistically significant reduction in the quality of angiograms (p = 0.0025) and ease of photography (p = 0.0012) was associated with 2 mL of NaFl, necessitating the termination of the study. Patients randomized to the 5 mL NaFl group experienced all 3 of the minor adverse events in the study. No statistically relevant conclusions could be obtained from this limited group.
Interpretation: Two millilitres of NaFl for IVFA produces inferior quality digital images compared with 5 mL of NaFl. The potential reduction in adverse events associated with 2 mL of NaFl becomes unimportant in light of this significant finding regarding image quality.