diff --git a/getopts.php b/getopts.php
index aae5dbc..b1e03e0 100644
--- a/getopts.php
+++ b/getopts.php
@@ -88,7 +88,8 @@ class getopts
       else
         $long = array ();
     }
-    if (substr ($short, 0, 1) !== false && $short[0] === ":")
+    if (substr ($short, 0, 1) !== false && substr ($short, 0, 1) !== "" &&
+        $short[0] === ":")
       throw new \Exception ("Short option can't start by semi-colon", 500);
     if ((strpos ($short, ":") !== false ||
          strpos (implode ($long), ":") !== false) &&
@@ -109,7 +110,8 @@ class getopts
     $short = $matches[0];
     foreach ($short as $key=>$s)
     {
-      if (substr ($s, 1) !== false && substr ($s, 1) !== ":")
+      if (substr ($s, 1) !== false && substr ($s, 1) !== ":" &&
+          substr ($s, 1) !== "")
         throw new \Exception (
           "Short parameter is invalid : only one letter allowed", 500);
       $short[$key] = "-".$s;