As I know, the oxygen is not the point, but the risk of get your lenses infected in the point. Yearly contacts can ensure you to use the contact lenses for almost one year, so during the daily use, you must be more careful about the maintain and cleaness of your lenses, they are easily broken and infected, or your eyes may suffer from eye diseases and infection.
To keep your eyes healthy, I think the monthly contacts is a good choice for you though they are more expensive than the yearly. However, the advantage o fthe monthly contacts is that there will be few deposits, especially proteins, on the lenses because you replace the lens very often. While the yearly contacts may have many deposits on the lens due to overtime use. The deposits can make your vision blurry and sometimes they can lead to chronic inflammation. So you'd better choose the monthly contacts.