Well from what you sre describing these symptoms can be due to a number of conditions which can include simple issues like migraines. Now most people assume that migraine would only occur if you have headaches which is not true there are types of migraines in which headache is not necessary. This could cause the vomiting on exposure to flashing lights. This would be diagnosed on a clinical examination and then treated with medications.
Another cause of this could be a minor seizure which can cause vomiting only without any seizures per se. There is an entity which is known as non convulsive seizures in which the body does not suffer any seizure but there is hyperactivity of the neurons in the brain. This can be excluded on the basis of a simple EEG and then treated with drugs.
Another cause can be associated with the blocked ears that you have. This could be indicative of an infection of the sinuses as well as the middle ear cavity. Infections which can be bacterial or viral in nature can both lead to this problem and cause the vomiting. This would also cause congestion and in some cases post nasal drip. hearing issues can also occur in many patients. A simple xray of the sinuses as well as CT scan and a ear examination would be diagnostic. The treatment would be with antibiotics in most cases.
There is an entity which is known as flicker vertigo in which you can have vomiting on exposure to flickering lights such as in the case of computer screens etc, this would cause vomiting, nausea, blinking of eyes and in some cases muscle rgidity. This again can be treated with various medications.
Now my suggestion is to start OTC anti emetics like dramamine but i would strongly suggest that you have this evaluated by visiting your doctor as soon as possible.
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