With eye pain, there may be other symptoms too, which may help diagnose the cause of the discomfort. These include: 1  Conjunctivitis-red itchy eyes. 2  Tears. 3  Light sensitivity (photophobia). 4  Discharge, which can be clear, or thick and coloured (pus). 5  The eye being crusted shut after sleep due to discharge.
The process of breathing performs a number of important gas exchanges through inhalation and exhalation. When someone inhales, they contract and move their diaphragm, which allows the lungs to expand. This is a part of the process needed to psychically suck in the air. When a person exhales, the diaphragm relaxes and the movement is undone. This allows air to be gradually pushed out of the lungs.
Thus, CO2 stops leaving your blood faster if the lungs are empty, meaning the CO2 levels in your blood reach critical faster and you need to breath sooner. Oxygen levels in your blood are likewise not rising fast enough (or at all, since you just exhaled), but it's the rise in CO2 that makes you gasp.