Here are some useful tools for seeing as well as general practice:
Counting from 100 to 0 and from 0 to 100 simultaneously during meditation.
Several things happen when doing his - for one thing it is pretty much impossible to think while you are doing this.
You will also generally see the count in front of you - one scaling down and the other scaling up - meeting at 50-50.
As you practice this more the process can become like a mantra somewhat but it tends to require focus.
Close your eyes and imagine your favorite food - or car - or place - something you have an affinity for.
If you have been having a problem with seeing/imagining things with your eyes closed, or you think you have a problem seeing things/imagining things, this exercise can often show you very clearly that you have no problem seeing things at all.
During your waking state with eyes open
Concentrate on being aware of your widest peripheral vision areas as well as all that is in between.
If you move your awareness from normal to wide you may also notice it affects your hearing.
This practice will affect your focus - not just visually but your thoughts and mindset.
You will notice energy entering the eyes and your energy will be considerably more in your head than out in front of you.
Have your awareness centered in the center of the head or anywhere in the central axis – Taiji pole. It is a far more neutral location and the traditional seal of embodiment.
Copywrite 2015 David A Doyle