- Normally, the eye is protected from barotrauma because the eye is filled with non compressible fluids, the aqueous and vitreous humors.
- A mask has air filled space that is compressible, affecting the eye and it’s adnexa.
- If the diver does not expel gas through the nose into the mask on descent, negative pressure develops inside this space, sucking the eyes and lids toward this space.
- This negative pressure results in marked lid edema and bruising as well as bleeding under the conjunctivae of the eyeballs. These changes look a lot worse than they really are but can be disconcerting to the diver and his buddy.
- Hyphema, a more serious injury, can occur in the eyes if the diver becomes unconscious and sinks to a greater depth without being able to equalize the mask. This can also result in bleeding under the periosteum of the bones of the orbit.
- Vitreoretinal surgery with air placed in the eye contraindicates diving so long as any of the bubble remains. Pressure induced changes in the volume of these bubbles may result in hemorrhage inside the eye and also may result in partial collapse of the eyeball.
