diff --git a/samples/InstanceLayerExtensionProperties/InstanceLayerExtensionProperties.cpp b/samples/InstanceLayerExtensionProperties/InstanceLayerExtensionProperties.cpp
index 3e3bf6c..1bf4e3e 100644
--- a/samples/InstanceLayerExtensionProperties/InstanceLayerExtensionProperties.cpp
+++ b/samples/InstanceLayerExtensionProperties/InstanceLayerExtensionProperties.cpp
@@ -49,7 +49,7 @@ int main( int /*argc*/, char ** /*argv*/ )
     for ( auto const & layerProperty : layerProperties )
     {
       std::vector<vk::ExtensionProperties> extensionProperties =
-        vk::enumerateInstanceExtensionProperties( std::string( layerProperty.layerName ) );
+        vk::enumerateInstanceExtensionProperties( vk::Optional<const std::string>( layerProperty.layerName ) );
       propertyData.push_back( PropertyData( layerProperty, extensionProperties ) );
     }