No longer maintained.
Vise is not compatible with OptiFine. Attempting to load Vise while OptiFine is installed will result in an error.
Vise is a small mod that replaces the GUI Scale button with a "Scale Settings..." button. This button leads to a separate screen with GUI Scale, HUD Scale, and Tooltip Scale sliders allowing you to independently adjust the scale of different elements of the game's UI.
Project icon is from The Noun Project - https://thenounproject.com/term/vise/577543