I noticed that in the evenings there was redness in his eyes, at first did not attach importance to, and then it became painful to blink, there was a feeling of a foreign body in the eyes. Optometrist put SSG and he told me that the drops that I used for humidification, with long-term use provoke dryness. Advised delfante, drink the second course until the flight is normal, his eyes returned to normal, drops no longer use.