Yes, what the flying means to us is to adapt to a totally different environment, in which the air is not natural. And high pressure outside leads to ocular hypertension causing vision loss or a drainage blockage. That is one of the reason why people of a long flight will experience headache. Flying in an atmosphere of lower oxygen levels has the most tough physiological effect, called dehydration. Your eyes may drier than desert when the humidity below 10 percent. Then it hurts, and you will find your vision deteriorated significantly after your trips. So, you need use extra lubricating drops with you and drink extra water. Besides that,you can ask the attendant to increase the airflow in the cabin and some oxygen for yourself.
Well, in my opinion, it is not possible to affect eye sight when you take plane. But on the other hand, when you are flying, it is possible to have some effects on your eyes. For example, eye strains can be possible. As we know that because of the gravity, the plane can give you a kind of pressure on your eyes, when it takes off. So that can lead to eye strains. And in some cases, high eye pressure can be possible. And then redness in the eyes can be possible too. But in common, it will be fine for most of people.
It's not true! The pressure in cabin has been set to fit for people's body. Only when the Plane land or take off that is the time plane will adjustment cabin pressure. So, the pressure in cabin won't harm the people's eyes. But in fact, not all people who are suitable for flying. Those person who have heart disease, hypertension or tympanitis must pay more attention.