Sadly, it is not possible for a single line of code in a file. See the MSDN docs.
On the other hand, you could probably make your single line of code a separate function, put that in a new file with partial class attributes, and put Option Strict Off on that one file. The IL compiler will probably inline your function anyway, so it will be equivalent speedwise, but will be ugly from a practical point of view.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…