diff --git a/src/spox/_fields.py b/src/spox/_fields.py
index 8d5a67a..aed590b 100644
--- a/src/spox/_fields.py
+++ b/src/spox/_fields.py
@@ -5,7 +5,7 @@
 import enum
 from collections.abc import Iterable, Iterator, Sequence
 from dataclasses import Field, dataclass
-from typing import Any, Optional, Union
+from typing import Any, Optional, Union, get_type_hints
 
 from ._attributes import Attr
 from ._var import Var
@@ -61,13 +61,14 @@ def __post_init__(self) -> None:
     @classmethod
     def _get_field_type(cls, field: Field) -> VarFieldKind:
         """Access the kind of the field (single, optional, variadic) based on its type annotation."""
-        # The field may be unannotated as per
+        # The field.type may be unannotated as per
+        field_type = get_type_hints(cls)[field.name]
         # from __future__ import annotations
-        if field.type in [Var, "Var"]:
+        if field_type == Var:
             return VarFieldKind.SINGLE
-        elif field.type in [Optional[Var], "Optional[Var]"]:
+        elif field_type == Optional[Var]:
             return VarFieldKind.OPTIONAL
-        elif field.type in [Sequence[Var], "Sequence[Var]"]:
+        elif field_type == Sequence[Var]:
             return VarFieldKind.VARIADIC
         raise ValueError(f"Bad field type: '{field.type}'.")