Which factor is indicative of contact lens hypoxia during retro illumination?

The correct answer is indicative of corneal swelling. In contact lens wear, hypoxia refers to the lack of adequate oxygen supply to the cornea, which is especially critical because the cornea relies on oxygen absorbed from the atmosphere and the tears for its health. When hypoxia occurs, one of the primary responses of the cornea is to swell due to fluid accumulation, which can be observed during retro illumination.

Retro illumination is a technique used to assess the cornea by shining a light onto its surface and evaluating the reflection. If corneal swelling is present due to hypoxia, this will manifest as a distortion in the normal reflection of light from the corneal surface, indicating that the cornea is not healthy.

Other factors, such as myositis, punctate staining, and excessive tearing, do not directly indicate hypoxia. Myositis concerns inflammation of the muscles and does not relate to corneal oxygenation. Punctate staining can suggest surface irregularities or dryness but isn't a sole indicator of hypoxic conditions. Excessive tearing might be a reaction to irritation but again does not reflect the hypoxic state of the cornea directly.

In summary, corneal swelling experienced during retro illumination reflects inadequate oxygenation of the cornea due