Mental Control[... The eye with perfect sight is always at rest. When it begins to
strain the sight becomes imperfect. The eye with imperfect sight is
always straining, and when it ceases to do so the sight becomes
normal. These conditions of rest and unrest are reflections of the
mind. In other words, they indicate the presence or absence of mental
control. The eye with imperfect sight is always straining, and when it
ceases to do so the sight becomes normal. These conditions of rest and
unrest are reflections of the mind. In other words, they indicate the
presence or absence of mental control...]
- Dr. W.H. Bates