Did you notice yellow bumps on the white part of your eyes?
What caused this is most likely ultraviolet from the sun.
Other causes include wind, dust and chemicals.
Always wear sunglasses (or Transitions) while outside.
Even if it is overcast. UV can go through clouds.
Diabetic retinopathy can usually be prevented by controlling diabetes.
If diabetic, make sure that your sugar level has been stable for 2-3 weeks before going to your eye exam, as sugar level affects your vision.
Mention all your diseases to your doctor.
Many medications cause side effects that can affect vision, or the health of the eye.
Tell your doctor about all the medications you take.