Acts 9:8

When his eyes were opened - He naturally closed them at the appearance of the light, and in his fright kept them closed for some time.

He saw no man - This darkness continued three days, Acts 9:9. There is no reason to suppose that there was a miracle in this blindness, for in Acts 22:11, it is expressly said to have been caused by the intense light. “And when I could not see for the glory of that light,” etc. The intense, sudden light had so affected the optic nerve of the eye as to cause a temporary blindness. This effect is not uncommon. The disease of the eye which is thus produced is called “amaurosis,” or more commonly “gutta serena.” It consists in a loss of sight without any apparent defect of the eye. Sometimes the disease is periodic, coming on suddenly, continuing for three or four days, and then disappearing (Webster). A disease of this kind is often caused by excessive light. When we look at the sun, into a furnace, or into a crucible with fused metal, we are conscious of a temporary pain in the eye, and of a momentary blindness. “In northern and tropical climates, from the glare of the sun or snow, a variety of amaurosis (gutta serena) occurs, which, if it produces blindness during the day, is named nyctalopia; if during the night, it is called hemeralopia. Another variety exists in which the individual is blind all day, until a certain hour, when he sees distinctly, or he sees and is blind every alternate day, or is only blind one day in the week, fortnight, or month” (the Edinburgh Encyclopedia’s “Surgery”). A total loss of sight has been the consequence of looking at the sun during an eclipse, or of watching it as it sets in the west. This effect is caused by the intense action of the light on the optic nerve, or sometimes from a disorder of the brain. A case is mentioned by Michaelis (Kuinoel in loco) of a man who was made blind by a bright flash of lightning, and who continued so for four weeks, who was again restored to sight in a tempest by a similar flash of lightning. Electricity has been found to be one of the best remedies for restoring sight in such cases.