According to the Catalan optometrist and amateur historian Simón de Guilleuma, Juan was married to Joana of Malaville, France, and migrated to the city of Girona, Principality of Catalonia, Spain, where he worked as a master spectacle maker.

Guilleuma referenced a book published in 1618, "Telescopium: sive ars perficiendi novum illud Galilaei visorium instrumentum ad sydera in tres partes divisa" (Telescope, or a performance of the art and means to Galileos's new vision of the stars, in three volumes)[4] by Italian author Hieronymi Sirturi Mediolanensis (aka Girolamo Sirtori of Milan) in which the author describes a 1609 meeting with a "withered old" spectacle maker in Girona named "Roget" who claimed to have invented the telescope.

In March of that year Pedro de Cardona, a prominent personality of the citizen oligarchy, and left among his assets a "long eyeglass decorated with brass"[5] (ullera llarga guarnida de llautó), carefully described by the clerk, who even highlights its optics and its elongated frame of about twenty centimeters (in units of its time).

[6] The claim was further investigated by writer Nick Pelling in an October 2008 History Today magazine article, in which he attempted to reconstruct the movements of Lipperhey and the other Dutch inventors before the patent application, and found that a connection with Roget was plausible.

Pelling agreed in a BBC interview that this could also describe a magnifying glass, adding that the reference to an "eyeglass/telescope for long sight" from 1608 sounds more like a Roget telescope.