Can I use an external camera with an app on my iPhone?

Episode 1518
Larry fromLarry wants to use his camera with Be My Eyes on his iPhone, an app for the vision impaired. Leo says the first thing he'll need is a camera that can connect over Wi-Fi. Then he would need an app to allow him to remotely control it from the iPhone. Leo says that iOS sandboxes each app for security purposes, so one app can't compromise others, so he likely won't be able to use a separate camera with that particular app.