Defocus curves v/s actual images

Posted , 4 users are following.

Just a thought. Wouldnt it be useful if people who have had monofocal lens implants set for distance could put up representative images of the actual extent of focus loss they have in the near and intermediate range so others could estimate what they would experience?

Example of a Snellen Chart images seen with visual acuity

  1. 20/50
  2. 20/100
  3. 20/200


1 like, 5 replies

5 Replies

  • Posted

    they should do it with an eye chart and a picture using a camera lens. even better when they do it if only one eye is operated and the other eye is fine.

    • Posted

      An actual out of focus picture would really be helpful. If someone who has already done a monofocal for distance can put up one so I know how blurred my vision inside three feet would look.

  • Edited

    The problem is that the Snellen chart is only used for distance vision. It is not useful for near and intermediate range vision. The Jaeger chart is normally used for that at 14" for distance. What you need to ask is what can you see on a Jaeger chart at 14". I see about J9 with my distance eye. Fortunately I can see J1 with my near eye. You can find a copy of a Jaeger chart at All About Vision - Eye Charts.

  • Edited

    It is meaningless to ask for what do you see without their numbers (e.g., 20/20, 20/32) for distance, immediate, and near without glasses. People have different ideas about what each distance is and what they have or don't know what they have. Then there is the matter of astigmatism whether corrected and to what extent affecting images. Other variables, too, like using one eye or both at each distance, or even the quality of their photos. One can only get information in terms of sample averages, as in the case of defocus curves.

  • Posted

    Can I ask what you are trying to accomplish with your questions about near vision using a monofocal? Most people will get good vision down to 2-3 feet, but it is very difficult to predict more exactly than that ahead of time.

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