diff --git a/tiny_gltf.h b/tiny_gltf.h
index ba44e65..6188dc0 100644
--- a/tiny_gltf.h
+++ b/tiny_gltf.h
@@ -108,7 +108,7 @@ namespace tinygltf {
 #define TINYGLTF_COMPONENT_TYPE_INT (5124)
 #define TINYGLTF_COMPONENT_TYPE_UNSIGNED_INT (5125)
 #define TINYGLTF_COMPONENT_TYPE_FLOAT (5126)
-#define TINYGLTF_COMPONENT_TYPE_DOUBLE (5130)
+#define TINYGLTF_COMPONENT_TYPE_DOUBLE (5130) // OpenGL double type. Note that some of glTF 2.0 validator does not support double type even the schema seems allow any value of integer: https://github.com/KhronosGroup/glTF/blob/b9884a2fd45130b4d673dd6c8a706ee21ee5c5f7/specification/2.0/schema/accessor.schema.json#L22
 
 #define TINYGLTF_TEXTURE_FILTER_NEAREST (9728)
 #define TINYGLTF_TEXTURE_FILTER_LINEAR (9729)