It is a basic symptom of acrophobia. Dizziness and tired are symptoms of acrophobia. For people suffers severe acrophobia, they also feel disgusted and unbalanced when they are in high place. Research shows that 91% of modern people have acrophobia of different levels. 10% of these people suffers severe symptoms which make them what to avoid being in high place anytime and anywhere. They will not even get on elevators or balcony. Not mention taking air flight. Experts believe that acrophobia has something to do with views. When you are looking downside from a high place, the view you have is blur and distant. The range of your eyesight shrinks a lot and becomes different from normal view which you are already get used to. Thus, you get more objects in your view but get less information. Therefore, your eyes may feel tire and heavy. It is not a big problem and requires no special treatment.
When you are high, your emotion is in the high state and the blood pressure is high. The eye pressure gets higher and makes the eye work in slow pace. The nerves of the eyes will be intense. That is why your eyes get tired easily. You should calm down by breathing several times.
Because if you feel the pressure from outside world, your eyes will irritate and they may become heavy and tired. When you are high, the air pressure will effect on your eyes in the same way. Besides, if you lack of sleep or in a state of stress, your eyes will have the feeling of heavy and tired as well. So you should let your eyes to have enough sleep and donâ€™t irritate them.