diff --git a/.gitignore b/.gitignore
index 696ddf85..ddd2edd8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,6 +26,7 @@ __pycache__/
 # Editor settings
 .idea/
 .vscode/
+.vs/
 
 # Temporary data files
 scripts/**/*.pickle
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0f8573e5..01000dd4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,12 @@ ZOS-API can also be added in patch releases.
 
 ### Removed
 
+## [[1.3.1]](https://github.com/MREYE-LUMC/ZOSPy/releases/tag/v1.3.1) - 2025-01-16
+
+### Fixed
+
+- Physical optics analysis start surface was hardcoded to 1 (#111, #112)
+
 ## [[1.3.0]](https://github.com/MREYE-LUMC/ZOSPy/releases/tag/v1.3.0) - 2024-10-30
 
 ### Added
diff --git a/zospy/analyses/physicaloptics.py b/zospy/analyses/physicaloptics.py
index 63d09b99..30ea6cc5 100644
--- a/zospy/analyses/physicaloptics.py
+++ b/zospy/analyses/physicaloptics.py
@@ -332,7 +332,7 @@ def physical_optics_propagation(
     if start_surface == "Ent. Pupil":
         analysis.Settings.StartSurface.SetSurfaceNumber(0)
     elif isinstance(start_surface, int):
-        analysis.Settings.StartSurface.SetSurfaceNumber(1)
+        analysis.Settings.StartSurface.SetSurfaceNumber(start_surface)
     else:
         raise ValueError(f'start_surface value should be "Ent. Pupil" or an integer, got {start_surface}')