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Question

FFT Through Focus MTF

  • September 5, 2024
  • 4 replies
  • 143 views

Karthick

Hi

 

I am working on to create a multifocal IOL. I don’t know how much add power is in the FFT through focus MTF. It shows the focus shift. how to convert t the focus shift into diopters or is there any option in the zemax for conversion.

 

Regards,

C.Karthick

4 replies

David.Nguyen
Luminary
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  • Luminary
  • 1089 replies
  • September 5, 2024

@Karthick 

 

I think you posted your question in the wrong section of the forum (Code Exchange).

As far as I know, this option isn’t available from OpticStudio directly.

You could extract the data and calculate the shift in diopters. I’m not at all an expert in ophthalmology (I rarely use diopters myself) but I imagine that if you have a focal shift of 2mm for example, and the nominal focal length is 200mm, the “shifted” focal length is 202mm. The diopter is one over the focal length in meters so the nominal diopter is 1 / 0.2 = 5dpt, and the shifted diopter is 1 / 0.202 = 4.95dpt. Therefore the shift is -0.05dpt. Again, I’m not totally sure that’s what you are after, so please double check this information.

Take care,


David


Karthick
  • Author
  • Single Emitter
  • 3 replies
  • September 8, 2024

Dear Sir, 

 

Thank you for your response.  But it is not correct. In relief type diffractive IOL design article the focus shift is around 0.65mm and the address power is 3.5D. it doesn't match the calculation which you mentioned above.

 

Once again thank you sir for your response.

 

 


David.Nguyen
Luminary
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  • Luminary
  • 1089 replies
  • September 9, 2024

@Karthick 

 

Sorry for the wrong calculation. Could you share the article you are talking about?

Take care,


David


Karthick
  • Author
  • Single Emitter
  • 3 replies
  • September 9, 2024

Dear Sir,

Please find the below mentioned article name.

Realistic modeling of relief-type diffractive intraocular lenses using User-Defined Surface DLLs

 

Authored By Csilla Timar-Fulep

 

Link: Realistic modeling of relief-type diffractive intraocular lenses using User-Defined Surface DLLs – Knowledgebase (zemax.com)

 

Regards,

C.Karthick


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