Posted by: juliegriffey | August 12, 2012

The Hammerhead and the Cyclops: Does Pupillary Distance Matter?

Last weekend I attended my husband’s medical school reunion where we met up with his old gross anatomy lab partner, Tom. Richard (my husband) and Tom had special nicknames for each other inspired by the differing distances each of them have between their eyes. Tom (the hammerhead) has a large, round head and his eyes sit far apart. Richard (the cyclops) has a longer, narrower face and his eyes are closer together.

So the two of them would giggle as they adjusted their microscope to accommodate their differing eye spacing. Then I think Richard bought Tom a rubber hammerhead shark to keep on their lab table. Hardy har har. Hilarious.

This got me thinking… how much variation is the distance between peoples’ eyes? Turns out, there is actually a term for it, “pupillary distance”. According to, there is no normal distance. For men, pupillary distance can range from 55mm to 70mm. This is a 27% difference. So, I think cyclops vs. hammerhead is quite an exaggeration.

How does pupillary distance affect vision? It doesn’t. So both a hammerhead and the cyclops could both have excellent vision.  Pupillary distance does make a difference when fitting a patient for glasses because it is used to make the glasses’ lenses to focus directly over a patient’s pupils.  So, next time your pupillary distance gets measured, you can learn whether you are a hammerhead or a cyclops.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: