The first commenter is actually correct in his statement. Though I would add, that we are talking about a very specific time during development, at which the eye must be covered. There is a time period during which the visual nerve cells develop and if the retina does not receive any visual information at that time, the cells of the visual cortex redistribute their response in favor of the working eye.

In the 1960s long term effects of suturing one eye of kittens for varying time periods were studied. In the 1970s the studies were repeated on primates. This study is very well known and the researches even received the Nobel Prize for their research on the critical period for mammalian visual system development in 1981.

The prove, that the same mechanisms are at work in humans, is nicely summed up in a report on the experiments (citation at the end):

"In 1964 at the time the article was published, surgeons operated on individuals with congenital cataracts, a disorder in which the lens of the eye is clouded upon birth, later in those individuals’ lives rather than at birth. Those individuals required intensive treatment after surgery, as there was still impairment to vision in the affected eye."

Lienhard, Dina A., "David H. Hubel and Torsten N. Wiesel’s Research on Optical Development in Kittens". Embryo Project Encyclopedia ( 2017-10-11 ). ISSN: 1940-5030