diff --git a/Code/IO/otbVectorDataKeywordlist.cxx b/Code/IO/otbVectorDataKeywordlist.cxx
index 8a89beda582fae701f19bf28a4a394001e63cd9a..2e41cc11fde47ab386c16bb7aabdb69efcc866b1 100644
--- a/Code/IO/otbVectorDataKeywordlist.cxx
+++ b/Code/IO/otbVectorDataKeywordlist.cxx
@@ -44,6 +44,9 @@ void VectorDataKeywordlist::
   FieldType newField;
   newField.first = fieldDefn;
   newField.second = *field;
+  //TODO: evaluate performance impact of fieldDefn copy
+  // the object itself could be handle at the VectorData level
+  // keeping only pointer here.
   m_FieldList.push_back(CopyOgrField(newField));
 };