If you have an older, drafty house, it can be kind of hard to keep temperature even and comfortable from room to room. We get a lot of inquiries here at Birdtricks about how cold is too cold for our parrots. The concerns generally stem from the knowledge that many parrot species originate from warm climates.
Astigmatism in only one eye may cause lazy eye (amblyopia) if present from birth. The affected eye does not 'learn' how to see because the brain ignores the signals it receives. Amblyopia can be treated with eye patching if diagnosed early enough, before the vision pathways in the brain are fully developed.
Astigmatism is a distortion of the image on the retina caused by irregularities in the cornea or lens of the eye. Combinations of myopia and astigmatism or hyperopia and astigmatism are common. Glasses or contact lenses are designed to compensate for the eye's imperfections.