Well, being an optician like myself, those who are also in the field will know about the changes that sometimes need to be made to the dioptres in ophthalmic prescriptions. As simple as it may seem, it would be useful to have a #Python function to perform this quickly. Here's my solution.

esf = -1.50
cil = -0.50
eje = 90
if eje >= 90:
    eje -= 90  
else:
    eje += 90

esfinv = esf+cil

if cil > 0:
    cil = -cil  
else:
    cil = abs(cil)  



print(f"esferico {esfinv} x cilindrico {cil} en {eje}°")
In this example the results are: *esferico -2.0 x cilindrico 0.5 en 0°*

Thank you in advance for viewing this post. If you have any feedback, whether positive or negative, I look forward to reading it. Namaste.