diff --git a/examples/osgkeystone/osgkeystone.cpp b/examples/osgkeystone/osgkeystone.cpp
index 13fe68101..fa0f16331 100644
--- a/examples/osgkeystone/osgkeystone.cpp
+++ b/examples/osgkeystone/osgkeystone.cpp
@@ -64,6 +64,19 @@ int main( int argc, char **argv )
 
     // add camera manipulator
     viewer.setCameraManipulator(new osgGA::TrackballManipulator());
+    
+    
+    OSG_NOTICE<<"KeystoneFileNames.size()="<<osg::DisplaySettings::instance()->getKeystoneFileNames().size()<<std::endl;
+    for(osg::DisplaySettings::FileNames::iterator itr = osg::DisplaySettings::instance()->getKeystoneFileNames().begin();
+        itr != osg::DisplaySettings::instance()->getKeystoneFileNames().end();
+        ++itr)
+    {
+        OSG_NOTICE<<"   keystone ="<<*itr<<std::endl;
+    }
+    
+    
+    
+    
 
     if (ds->getStereo())
     {
diff --git a/src/osg/DisplaySettings.cpp b/src/osg/DisplaySettings.cpp
index 3ff7a7c07..a44c3b63c 100644
--- a/src/osg/DisplaySettings.cpp
+++ b/src/osg/DisplaySettings.cpp
@@ -292,6 +292,9 @@ static ApplicationUsageProxy DisplaySetting_e26(ApplicationUsage::ENVIRONMENTAL_
 static ApplicationUsageProxy DisplaySetting_e27(ApplicationUsage::ENVIRONMENTAL_VARIABLE,
         "OSG_SWAP_METHOD <method>",
         "DEFAULT | EXCHANGE | COPY | UNDEFINED. Select preferred swap method.");
+static ApplicationUsageProxy DisplaySetting_e28(ApplicationUsage::ENVIRONMENTAL_VARIABLE,
+        "OSG_KEYSTONE_FILES <filename>[:filename]..",
+        "Specify filenames of keystone parameter files. Under Windows use ; to deliminate files, otherwise use :");
 
 
 void DisplaySettings::readEnvironmentalVariables()
@@ -585,6 +588,31 @@ void DisplaySettings::readEnvironmentalVariables()
         }
 
     }
+    
+    if ((ptr = getenv("OSG_KEYSTONE_FILES")) != 0)
+    {
+    #if defined(WIN32) && !defined(__CYGWIN__)
+        char delimitor = ';';
+    #else
+        char delimitor = ':';
+    #endif
+    
+        std::string paths(ptr);
+        if (!paths.empty())
+        {
+            std::string::size_type start = 0;
+            std::string::size_type end;
+            while ((end = paths.find_first_of(delimitor,start))!=std::string::npos)
+            {
+                _keystoneFileNames.push_back(std::string(paths,start,end-start));
+                start = end+1;
+            }
+
+            std::string lastPath(paths,start,std::string::npos);
+            if (!lastPath.empty())
+                _keystoneFileNames.push_back(lastPath);
+        }
+    }
 }
 
 void DisplaySettings::readCommandLine(ArgumentParser& arguments)
@@ -664,6 +692,17 @@ void DisplaySettings::readCommandLine(ArgumentParser& arguments)
         _numMultiSamples = atoi(str.c_str());
     }
 
+    if (arguments.read("--keystone",str))
+    {
+        if (!_keystoneFileNames.empty()) _keystoneFileNames.clear();
+        _keystoneFileNames.push_back(str);
+        
+        while(arguments.read("--keystone",str))
+        {
+            _keystoneFileNames.push_back(str);
+        }
+    }
+
     while(arguments.read("--cc"))
     {
         _compileContextsHint = true;