Lower eyelid began twitching incessantly 24 hours ago. Younger brother has same issue on opposite eye, yet his started a couple years ago and comes and goes. Ages: 24 and 19. Worried that it might be due to compression and/or damage of the facial nerve by the vertebral artery. What steps can I take that will provide clues about the cause of the twitch?
Eye twitching is often caused by fatigue and stress and can cease by its own. It can last for some days, weeks or even months. You have to avoid coffee and stressful or tiring situations and activities.  You can use lorazepam for some days, also. Rarely it can be a sign of some disease such as Bells palsy and Tourette syn Chat Doctor.  According to your concern about the relation of vertebral artery and facial nerve: if the facial nerve has any abnormality and if it presents with spasms , someone should have bifacial (half of the face) spasms. You can see a neurologist to undergo the objective examination.