When looking at a particular client's metrics, you can easily sort by certain categories to easily see the info you want to look at.
Go to your Client Index page and find a particular client. Select the client then go to the client's metric or photo page.
Then below All Metrics in the left toolbar under the client, you will see any Metric Categories.
Click on the Category you want to view for that client.
You can only view one collection at a time. If you have a mix of photo and numeric metrics within the same collection, they will just show up on their respective tabs.