partial blindness in his left eye; inability to maintain his balance; This spontaneous case was reported by a patient and describes the occurrence of VISUAL IMPAIRMENT (partial blindness in his left eye) and BALANCE DISORDER (inability to maintain his balance) in an 81-year-old male patient who received SPIKEVAX NOS (SPIKEVAX NOS) (batch no. 044C22A) for COVID-19 prophylaxis.     The patient's past medical history included COVID-19 (At Christmastime he got COVID. He spent a month in the hospital.) and Leg paralysis (He couldn't use his legs and had to learn how to use them. Then he recovered most of his ability.).    On 17-Mar-2023, the patient received first dose of SPIKEVAX NOS (SPIKEVAX NOS) (unknown route) 1 dosage form. On an unknown date, the patient experienced VISUAL IMPAIRMENT (partial blindness in his left eye) and BALANCE DISORDER (inability to maintain his balance). At the time of the report, VISUAL IMPAIRMENT (partial blindness in his left eye) and BALANCE DISORDER (inability to maintain his balance) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Biopsy artery: Negative. On an unknown date, Computerized tomogram head: Negative. On an unknown date, Echocardiogram: Negative. On an unknown date, Magnetic resonance imaging head: Negative. On an unknown date, Magnetic resonance imaging neck: Negative. On an unknown date, Ophthalmological examination: Negative. On an unknown date, Ultrasound Doppler: Negative.     The action taken with SPIKEVAX NOS (SPIKEVAX NOS) (Unknown) was unknown.       Concomitant product use was not provided by the reporter.  Patient was not sure if he received a bivalent vaccine, but he only received one shot.  It was reported that shortly thereafter he woke up with partial blindness in his left eye and inability to maintain his balance. He went through a series of tests, ultrasounds of carotids, Computed tomography (CT) scan in the back of his head, ophthalmologist did artery biopsy, vision tests, brain Magnetic resonance imaging (MRI), Magnetic resonance imaging (MRI) of cervical, heart echocardiogram, everything was negative. There was no proof of him having those issues. Only thing which come up was the vision issue was a direct result of the vaccine. There was nothing about why he couldn't maintain his balance. He was partially blind in his left eye now. He just woke up one morning and couldn't see out of his left eye. The top half of his left eye is like someone draped a black cheesecloth and the bottom half was blurry. There were times where he tries to look at something to see, the abnormal effects in the left eye go over to his right eye and he has to blink a few times to get reoriented in order to see from his right eye. He did not know if there was something that could be done about it. He should had said no to getting the vaccine. He made a mistake, and now he was paying for it. He never went to the doctor, maybe a checkup here and there with bloodwork. He never had the flu. He had a good immune system because he wore a mask and stayed away from people. He thinks something damaged his optic nerve. He states that his bad eye interferes with his good eye.  Treatment information was not provided.  He filed a report with VAERS. He contacted the health department where he got the vaccine, but he thinks they swept it under the rug.