DEAR DR. ROACH: My father is in his mid-60s and recently underwent surgery to repair mitral valve prolapse. Everything went smoothly, and his recovery has been good, with the exception of this morning. He has resumed smoking (after telling his doctors that he quit), and he experienced a dizzy spell where his vision in one eye became hazy, then gray, then black. His blood pressure was fairly high at this time. He sat down, and after several minutes, his vision slowly returned.

News Source : https://www.oregonlive.com/advice/2024/05/dear-doctor-is-smokers-dizzy-spell-temporary-vision-loss-cause-for-concern.html