Whether you use a Mac Laptop or Desktop machine, your body posture when viewing the Display is very important. It is especially important for your neck and head. The correct posture has been known for years, but this article which reviews screen viewing posture is a good reminder for all of us. I needed to tuneup my iMac viewing posture, you may need to as well. I think people using Laptops are in a more difficult position than the rest of us because the Laptop is usually sitting on a table or desk and the user is looking down at it.