diff --git a/autolens/lens/tracer.py b/autolens/lens/tracer.py
index b4cf929d6..e1b6811d9 100644
--- a/autolens/lens/tracer.py
+++ b/autolens/lens/tracer.py
@@ -247,7 +247,7 @@ def total_planes(self) -> int:
 
     @aa.decorators.to_grid
     def traced_grid_2d_list_from(
-        self, grid: aa.type.Grid2DLike, xp=np, plane_index_limit: int = Optional[None]
+        self, grid: aa.type.Grid2DLike, xp=np, plane_index_limit: Optional[int] = None
     ) -> List[aa.type.Grid2DLike]:
         """
         Returns a ray-traced grid of 2D Cartesian (y,x) coordinates which accounts for multi-plane ray-tracing.
diff --git a/autolens/lens/tracer_util.py b/autolens/lens/tracer_util.py
index fb3b24c22..9b9186fed 100644
--- a/autolens/lens/tracer_util.py
+++ b/autolens/lens/tracer_util.py
@@ -175,7 +175,7 @@ def traced_grid_2d_list_from(
     planes: List[List[ag.Galaxy]],
     grid: aa.type.Grid2DLike,
     cosmology: ag.cosmo.LensingCosmology = None,
-    plane_index_limit: int = Optional[None],
+    plane_index_limit: Optional[int] = None,
     xp=np,
 ):
     """
diff --git a/autolens/point/max_separation.py b/autolens/point/max_separation.py
index 411771014..aa7f22639 100644
--- a/autolens/point/max_separation.py
+++ b/autolens/point/max_separation.py
@@ -24,7 +24,7 @@ def __init__(
         data: aa.Grid2DIrregular,
         noise_map: Optional[aa.ArrayIrregular],
         tracer: Tracer,
-        plane_redshift: float = Optional[None],
+        plane_redshift: Optional[float] = None,
         xp=np,
     ):
         """