When creating a new world, when you appear on the map, this will not stop flashing, occurs with high grass, common grass, flowers, etc.
Environment
Win7, 1.60 Ghz x2, Intel Dual Core, Java Version 1.7.0_45
Nvidia 610M Graphic Card, 478 GB HDD, 4GB VRAM, DirectX 11, 64x O.S
Well, it's great that you didn't attach a screenshot so I can't see what "this" is, but does the issue go away if you're not holding any item in your hand?