When Samuel puts on the right pair of glasses in the drug store he can now see close up but also in the distance. He needs glasses to read up close meaning he's farsighted so the lenses would be blurry for distance but they show him seeing everything clearly.
Although the opening narration and the series' general progression place the action in 1935, two current events reported on by students--the Peace Conference in Brussels and the specific trans-Atlantic flight described by Jim-Bob--both occurred in the first few days of September, 1936.