Editing Corrective lens (section)

==== Trivex ====
* [[Refractive index]] ({{mvar|n}}{{sub|d}}): 1.532
* [[Abbe number]] ({{mvar|V}}{{sub|d}}): 43–45 (depending on licensing manufacturer)
* [[Density]]: 1.1 g/cm³ (the lightest corrective lens material in common use)
* [[Cutoff (physics)|UV cutoff]]: 394&nbsp;nm

Trivex was invented by Edwin C. Slagel and patented in September 1998.<ref name="patent">
{{cite patent
 | country = US
 | number  = 6127505
 | status  = Expired
 | title   = Impact resistant polyurethane, and meteor of manufacture thereof
 | pubdate = 3 October 2000
 | gdate   = 3 October 2000
 | fdate   = 2 September 1998
 | pridate = 2 February 1995
 | inventor= Slagel, Edwin C.
 | assign1 = Simula, Inc.
 | url     = https://patentimages.storage.googleapis.com/da/bd/da/1ce12187652eef/US6127505.pdf
}}
</ref>

Trivex was developed in 2001 by [[PPG Industries]] for the military as transparent armor.<ref name=eyecarebusiness-2001>{{cite news |last=Bruneni |first=Joseph L. |date=1 September 2001 |title=Alternative lens material |website = Eyecare Business |url=http://www.eyecarebusiness.com/articleviewer.aspx?articleID=50369 }}</ref> With [[Hoya Corporation]] and Younger Optics, PPG announced the availability of Trivex for the optical industry in 2001.<ref name=eyecarebusiness-2001/> Trivex is a urethane-based pre-polymer.<ref name=patent/> PPG named the material Trivex because of its three main performance properties: Superior optics, ultra lightweight, and extreme strength.<ref name=eyecarebusiness-2001/>

Trivex is a relative newcomer that possesses the UV-blocking properties and shatter resistance of [[polycarbonate]] while at the same time offering far superior optical quality (i.e., higher Abbe number) and a slightly lower density. Its lower refractive index of {{nobr| {{mvar|n}}{{sub|d}} {{=}} 1.532 }} vs. polycarbonate's 1.586 may result in slightly thicker lenses depending upon the prescription. Along with polycarbonate and the various high-index plastics, Trivex is a lab favorite for use in rimless frames, owing to the ease with which it can be drilled and its resistance to cracking around the drill holes. One other advantage that Trivex has over polycarbonate is that it can be tinted.{{Citation needed|date = January 2015}}