For last 15 days, I have had three occurrence, when, I just getting my vision blurred for some one to two hours or more with front black spot, almost not able to see anything in front of me which is then followed by headache (and little bit of nausea) which is very painful if am coughing or sneezing. This headache is remaining for next full day with little bit of weakness. I am managing without any pain killer by resting alone. and this is triggering always in afternoon when I am in front of workstation PC. This s first time I am facing this issue, I am 43 years old, with seasonal asthma issue.