Setting up an S3 notification for a read operation

I am trying to get a notification each time an S3 object is opened (read), and wondering if this is possible using S3 notifications. We are using a barcode scanner to open pdfs stored as S3 objects.

I found a tutorial somewhere on how to do this: "For the "Events" section, select the "All object read operations" or choose "Specific object read operations" and check "GetObject". This will trigger the event when an object is opened (read)."

Here's where I'm looking for notifications: S3 bucket > Create event notification > ("Specific object read operations") - cannot find this trigger.

So, is there a way to send a notification or trigger a Lambda function when an object is opened?