diff --git a/README.rst b/README.rst
index 5b94d7b..c2e0c87 100644
--- a/README.rst
+++ b/README.rst
@@ -150,7 +150,7 @@ Available test cases
 
   - FONT_VALIDATE_INDEXES (optional)
 
-    Set a index number to validate a specific face only.
+    A comma-separated list of index numbers to validate a specific face only.
 
 .. [1] compatible with Extended Regular Expression in grep. see grep(1) for more details.