Like it or not, surgical masks have become a daily essential recently, and can be a real nuisance to wear, especially for spectacle users.
Although it shields us from possible contamination, the fogging up of our glasses whenever we breathe, eat, or step out of air-conditioning can be an inconvenience. Wouldn’t it be great if there was a magic cure to spectacle fog?
According to MPD_bousai, a Japanese Twitter account, there are, in fact, multiple simple ways to prevent spectacle fog, so you have crystal clear vision all day!

The first method (first three images, above) involves simply folding in the top part of your mask to lessen the area where the fog forms, and the second method (last three images, above) requires a thin strip of tissue to be placed on the top half to help prevent fog. To further reduce the appearance of fog, you can also wear your glasses on top of your mask, like in the Tweet below.
ニュースサイトしらべぇ
警視庁考案
メガネが曇らないマスクの付け方マスクを付けると
メガネが真っ白になって
不便だなと思っていたのだが
これは素晴らしいアイデア??
マスクの上部を内側に折るだけで
曇りを防げるのならば簡単だし
付け心地に影響なし
今後マスクを付ける時は
これを実践しよう pic.twitter.com/ngZPNF64fH— ジェームズ・T・カーク2世 (@kirk2_thegod) January 30, 2020
An alternative is to wash your spectacles beforehand with soapy water, before letting it air dry (do not wash off the soap!). The soap now forms a thin film on the surface of the glass that prevents fog. View the more detailed explanation here.