so fun* fact, there never was an official order relating to glasses, and indeed Pol Pot himself as well as several other senior Khmer Rouge minister publicly wore glasses. But what they did do was set up a system were city folk and intellectuals were treated with a level of suspicion high enough that any low-level Khmer Rouge member could cite the ownership of glasses as sufficient evidence to execute someone for being a counter-revolutionary.

https://www.shadowsofutopia.com/blog/did-the-khmer-rouge-really-kill-everyone-who-wore-glasses