From the reference, the Vix Whitepaper of CBOE, I found the formula of VIX.
There are two terms. The first one is focusing on the info from Option contracts. And the second one is focusing on the relationship between the forward index and strike price.
In addition, there is a part to illustrate the forward index.
I am confused with the purpose of the second term and the forward index.
I appreciate any help to explain that!
**Reference : https://www.cboe.com/micro/vix/vixwhite.pdf