diff --git a/src/Geometry/Primitives/AsphericSurface.jl b/src/Geometry/Primitives/AsphericSurface.jl
index aaf74dfa5..e30564b40 100644
--- a/src/Geometry/Primitives/AsphericSurface.jl
+++ b/src/Geometry/Primitives/AsphericSurface.jl
@@ -58,7 +58,7 @@ struct AsphericSurface{T,N,Q,M} <: ParametricSurface{T,N}
         @assert one(T) - (1 / radius)^2 * (conic + one(T)) * semidiameter^2 > 0 "Invalid surface (conic/radius combination: $radius, $conic)"
 
         acs = []
-        if aspherics===nothing || aspherics == []  #AxisymmetricOpticalSystem sends a null array 
+        if aspherics===nothing #|| aspherics == []  #AxisymmetricOpticalSystem sends a null array 
             M = CONIC
          else
             asphericTerms = [i for (i, ) in aspherics]
diff --git a/src/Optical/OpticalSystem.jl b/src/Optical/OpticalSystem.jl
index c9d9d5538..9680ecabb 100644
--- a/src/Optical/OpticalSystem.jl
+++ b/src/Optical/OpticalSystem.jl
@@ -279,6 +279,8 @@ function get_front_back_property(prescription::DataFrame, rownum::Int, property:
     return replace(properties, missing => default)
 end
 
+turnEmptyIntoNothing(list) = length(list)==0 ? Nothing : list
+
 """
     AxisymmetricOpticalSystem{T,C<:CSGOpticalSystem{T}} <: AbstractOpticalSystem{T}
 
@@ -374,12 +376,21 @@ struct AxisymmetricOpticalSystem{T,C<:CSGOpticalSystem{T}} <: AbstractOpticalSys
                 frontaspherics::Vector{Pair{Int,T}}, backaspherics::Vector{Pair{Int,T}} = [
                     [parse(Int, k) => v for (k, v) in params] for params in [frontparams, backparams]
                 ]
-
-                newelement = AsphericLens(
-                    material, vertices[i-1], frontradius, frontconic, frontaspherics, backradius, backconic,
-                    backaspherics, thickness, semidiameter; lastmaterial, nextmaterial, frontsurfacereflectance,
-                    backsurfacereflectance
-                )()
+                
+                fa = turnEmptyIntoNothing(frontaspherics)
+                ba = turnEmptyIntoNothing(backaspherics)
+                if fa === nothing && ba === nothing  #it should be a CONIC. Note: if aspheric terms are present but all zero then an AshpericLens will be created
+                    newelement = ConicLens(
+                        material, vertices[i-1], frontradius, frontconic, backradius, backconic, thickness,
+                        semidiameter; lastmaterial, nextmaterial, frontsurfacereflectance, backsurfacereflectance
+                    )()
+                else    
+                    newelement = AsphericLens(
+                        material, vertices[i-1], frontradius, frontconic, fa, backradius, backconic,
+                        ba, thickness, semidiameter; lastmaterial, nextmaterial, frontsurfacereflectance,
+                        backsurfacereflectance
+                    )()
+                end
             else
                 error(
                     "Unsupported surface type \"$surface_type\". If you'd like to add support for this surface, ",