On older Radeon cards, some versions of AMD Catalyst Control Center (CCC) allow you to override application mipmap settings and choose between performance and quality. The higher you set the slider to "Performance," the blurrier the texture becomes. Conversely, moving the slider towards "Quality" sharpens your images and hud elements.
Some users who have older versions of CCC have reported that their blurry HUD elements issue were fixed by moving the slider more towards "Quality".
On newer AMD Radeon cards with the new versions of CCC have found that changing the setting called "Texture Filtering Quality" (where it used to be Mipmapping has helped resolve blurry HUD/Inventory/Main Menu issues. You'll find the option under 3D Application Settings - change the setting to High Quality, accept the change, and run Don't Starve.
You can find out more information about this fix here: http://forums.kleientertainment.com/index.php?showtopic=22522#post243879