Hello Mandy-k,

I'm sorry to hear about your diagnosis. Herceptin can cause side effects in the eye, like blurred vision, but it's not certain that it could have caused this. Hopefully your appointment with the eye specialist can shed some light on this and the possible next steps. If need more information on ratinal vein occulsion, you can find this information and more on the Royal National Institute of Blind People website.

I hope this helps,

Moderator Anastasia