If you have the computer for it, go to Properties > Misc > Change 'Grids to Load' to a higher number. (Default is 5) Note: It has to be an odd number. So try 7, or 9.
Alternatively, if you're worldspace has LOD, you can turn LOD on by going to Properties > LOD > and checking 'Enable Landscape LOD'. Note, this LOD may be outdated if you've heavily altered the worldspace since it was generated, and it can cause some inconveniences when editing, so if you're having issues turn it off while you work. Then, turn it back on when you need a good look at the land.