[QUOTE=BigMama1;8567905]
Instead of cutting across, keep the scissors vertical (parallel with the hair) and snip tiny bits at a time as you move across.
Cutting straight across will make your horse look like Justin Bieber!
If thickness is the real problem, not length, use a thinning knife[/QUOTE]
I second this! There are thinning shears that you can buy such as these if thickness is the issue. Otherwise, cut the hair vertically, scissors parallel to the hair
We had a horse that had headshaking sydnrome and, during diagnosis, the vet cut his forelock straight across (he thought the hair might be irritating him) and he looked every bit the part of Lloyd from Dumb and Dumber. The name stuck!