12

Hieronymi Sirturi drc.

J$uis & quetuplex perfyialiorum vfus ¥ CAPVT 11.

pLurimseartes, quje vifusacumine,&yalidaoculorutrt ^ acie indigent, vc aflidua leflio^fcriputatio^cselatura perfpicillorum vfum expofcunt,& hanc artem induxere. Senes pr«terea,&ii quibus natura aut morbo breuis & la- befa&atus eft vifus, hi Myopes illi presbytasab Ariftotele vocantur,neccffario hoc indigent adminiculo vnde mul­tiplices emanant perfpicillorum differentiae.

Nonnulli tardius aut citius perfpicilhs indigent, idque- cx pluribus caulis oriri operaepretium erit demonltrare. Literati imprimis, quiafliduisftudijs femacerant, faepe; fatigant oculos,non folumimmodicale&ione,&: (ludio,, verum librorum,minutis literis quib.nil citius viflim he­betat,adeo vt vniushuiufmodi libri le&iooculorum fa- nitatem in difcrimen adducere poflit. Monetperfpedi- uaobie&abali pupillae minora vilionem efficere doloro- fam,vt pote nimis coardansradics,cuius rei experimen­tum praebet cauifpicillitranfuerberatio , fiueretra&ioj quae cum radiosadeentrum pra;ftringat, oculos hedine- ceffeeft^

Secundacaufa,quaeaccelerat vfum perfpicillorum, eff luminis deficientia, loci obfcuritas, aut lychni parcitas, quibus oculi dum affuefeere conantur, Yim fuam magis intendunt,& violenter femper intuendo citius hebetan­tur*

Tertia caufa ex hominum incuria nalcitur,qui nefeiut: £bitcpcrare,aut prascauereanoxijs, cum fcilicet fatiga­ti^