Restrict user role Author from viewing comments in admin interface

For a user to be able to see the list of other users in wp-admin, he or she needs the capability list_users, to be able to edit existing profiles, he or she needs edit_users, to add new ones add_users and to delete old ones delete_users.

For managing a site with multiple specific user roles that need to have certain capabilities and not to have others, I highly recommend using a mixture of two plugins:

Adminimize gives you control over what part of the admin interface is shown to what role

Members lets you edit the capabilities of a specific role and add new roles as needed