Effects of patent blue on human retinal function.

Background: Dye solutions for intraoperative staining of epiretinal membranes and the internal limiting membrane improve the visualisation of these thin structures and facilitate their removal. Lately, the application of patent blue for staining of the internal limiting membrane has been proposed as an alternative to the standard procedures during macular hole surgery. In the present study we investigated the effects of patent blue 0.48% on human retinal function.

Methods: An isolated human retina preparation was perfused with a standard solution and the electroretinogram (ERG) was recorded repeatedly. After recording of stable ERG amplitudes the nutrient solution was substituted by a commercially available patent blue solution. The duration of retinal exposure to the dye solution was varied between 15 s and 4 min. Thereupon, the preparation was reperfused with standard solution for 2 h. The percentage of b-wave reduction after exposition was calculated.

Results: No effects on the human ERG were seen after 15 and 30 s of dye application. Reversible reductions of the b-wave amplitude were found for an exposure period of 60 and 120 s, respectively. After 4 min of patent blue application a persistant b-wave amplitude reduction by 40% was found.

Conclusions: Patent blue affects human retinal function when applied for at least 1 min. However, no irreversible effects on the human ERG were seen even after 2 min of retinal exposure to patent blue. Thus, toxic effects on retinal function after intraoperative short-term application of patent blue 0.48% appear unlikely to occur.