The Enable Secure Markups option on the Workflow Configuration page allows you to set up a workflow, so that access to all of the markups is restricted while the item moves through the workflow.
For example, you can set up a workflow so that only the panel members of a workflow node can view the item markups. The primary use of this feature is to prevent the users that are uploading documents from seeing unapproved markups.
Click here for steps to set up a workflow to use this feature.