Yes, it is. Carbon monoxide is harmful to people. It is called the silent killer for it can't be smelled, tasted or seen. It might poison people without a warning when there is a high concentration. Long time exposure to low concentration of carbon monoxide would cause some symptoms similar to a flu, such as the headaches, fatigue, nausea, dizziness, drowsiness, vomiting, weakness and diarrhea. Other possible symptoms might be caused including burning of eyes, red skin, confusion and irritability. It might poison people gradually through a period of several hours by accumulating in the blood. As the it accumulating, vomiting, consciousness loss and even brain damages would be caused and finally people would die. There are no other apparent impact on eyes after all it is lethal, nothing can be compared with death, right? If you are suspect yourself of carbon monoxide poisoning, you should get fresh air at once. If symptoms linger or worsen, you should go to hospital immediately.
The carbon monoxide is really bad to your body as well as your eyes. The mild intoxication of person may appear the symptom as headache, faint, insomnia, vision blur, tinnitus, nausea, vomit etc. As for the damage to the eyes, once the carbon monoxide contacts the optic nerve, the hemoglobin will combine with carbon monoxide, it will stimulate the nerves, choroid, crystalline lens with pain. The carbon monoxide will let your body lack of oxygen including the eyes. From the study we can find the chance of getting cataracts will be double than the normal people of the smoker who often contact with carbon monoxide.