One of the more ubiquitous medical apps on my colleagues’ phones and tablets is a Snellen eye chart. I confess I used to use one, too — back when Apple made one size of mobile screen. And I trusted the app developer’s instructions when it read, “hold phone four feet away from patient’s eye.”

When I got my iPhone 6 I expected app makers to update instructions for the larger screen —hold device five feet back? Six? Would it check to see if I was using a 5s, 6 or 6 Plus?

But that update never happened. Then I realized none of the iTunes App Store’s Snellen apps has been updated … in years.

Why should this be? I wonder if the app makers got scared that the FDA would classify these apps as medical devices. Unlike med calculators and references apps, we are using Snellen apps to measure patient characteristics and make medical decisions — close to the FDA’s definition.

In any event, as I pointed out in my recent talk on med apps — it’s sad that as mobile medical technology marches forward, this is one area where I’m going back to paper.