They use mixture of Insulin and a chemical known as "Ce6" (Chlorin e6) as eye drop for getting the night vision. It allows the user to view the objects clearly up to 50 meters in darkness.
This chemical "Ce6" is found in some deep-sea fish and is often used to treat cancer and night blindness.
The Ce6 solution will start work in as little as one hour after getting injected into eyes using micropippette. And the Night vision effect will be lasting for “many hours” afterwards, and the test subject's eyesight will become normal the next day.
The organisation "Science for the Masses" has released a paper that detailed the experiment in their website."