how is it structured?
A typical tropical cyclone will have an eye of approximately 30–65 km (20–40 mi) across, usually situated at the geometric center of the storm. The eye may be clear or have spotty low clouds (a "clear eye"), it may be filled with low- and mid-level clouds (a "filled eye"), or it may be obscured by the central dense overcast.
Eye (cyclone)
A typical tropical cyclone will have an eye of approximately 30–65 km (20–40 mi) across, usually situated at the geometric center of the storm. The eye may be clear or have spotty low clouds (a "clear eye"), it may be filled with low- and mid-level clouds (a "filled eye"), or it may be obscured by the central dense overcast.
is there oxygen in the eye of a tornado UNANSWERABLE what is meant by the eye of a cyclone? It  is a region of mostly calm weather at the center of strong tropical cyclones.
wiki:23065888
Eye (cyclone) [SEP] Structure
While normally quite symmetric, eyes can be oblong and irregular, especially in weakening storms. A large "ragged eye" is a non-circular eye which appears fragmented, and is an indicator of a weak or weakening tropical cyclone. An "open eye" is an eye which can be circular, but the eyewall does not completely encircle the eye, also indicating a weakening, moisture-deprived cyclone. Both of these observations are used to estimate the intensity of tropical cyclones via Dvorak analysis. Eyewalls are typically circular; however, distinctly polygonal shapes ranging from triangles to hexagons occasionally occur. While typical mature storms have eyes that are a few dozen miles across, rapidly intensifying storms can develop an extremely small, clear, and circular eye, sometimes referred to as a "pinhole eye".