diff --git a/runtime/optwin.vim b/runtime/optwin.vim
index 82e2c0c..98ac00e 100644
--- a/runtime/optwin.vim
+++ b/runtime/optwin.vim
@@ -1147,6 +1147,10 @@
 call <SID>BinOptionL("bl")
 call append("$", "debug\tset to \"msg\" to see all error messages")
 call append("$", " \tset debug=" . &debug)
+if has("mzscheme")
+  call append("$", "mzquantum\tinterval in milliseconds between polls for MzScheme threads")
+  call append("$", " \tset mzq=" . &mzq)
+endif
 
 set cpo&vim