IOLmaster vs A-scan

Posted , 2 users are following.

Is IOLmaster intended mostly for multifocal lens? Is A-scan accurate enough for monofocal IOLs? I have decided to use monofocal lens for both eyes, and just wonder if it is helpful or worthwhile to get IOLmaster scans before surgeries.

0 likes, 6 replies

6 Replies

  • Posted

    Unless you have a very advanced and dense cataract I think it would be a serious mistake to use an ultrasonic scan instead of the optical measurement used in the IOLMaster 700 or Lenstar 900. An ultrasound scan has to touch the eye or nearly touch the eye to get a reasonably accurate length of eye measurement. This measurement is the most critical in determining what power of lens you need. A monofocal is even more critical to get the power right as an extended depth of focus lens and some multi focal lenses have some forgiveness in the power.

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    These days an ultrasonic method is only used when the cataract is so dense you can't use an optical instrument. Or, it could be used to save some costs when the patient does not care about getting an exact outcome because they plan to wear glasses no matter what they get.

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    Are you considering a toric lens? That too needs more advanced measurement to get the astigmatism magnitude and angle correct. The IOLMaster 700 can do it, and usually a Pentacam is also used to get a second reading. Again, if the plan is to wear glasses, there is no real need to correct astigmatism with an IOL.

  • Edited

    I just reviewed your initial post here and you mentioned you have 20/25 vision in your right eye, and 20/200 in the left eye? Is that before correction with eyeglasses? If it is and you get 20/20 vision with eyeglasses you should have the option of getting 20/20 vision in both eyes without glasses if you want to, as long as the power of the IOL is correct. But with a monofocal you will need reading glasses.

    • Edited

      Thank you again, RonAKA.

      I understand I can get 20/20 in both eyes, but my surgeon is trying to pursuade me to target near. According to my surgeon, I am accustomed to wearing glasses, and it is better to stay that way. Anyway I will try to get an IOLmaster measurement first.

      One more question - no matter what surprises I may get post surgery, can I always rely on a good pair of progressive glasses to optimize my vision for both eyes?

    • Posted

      Yes, if you stick with monofocal lenses your eyes should be easily correctable with progressive eyeglasses. With respect to setting the lens for close, intermediate, or distance, eyeglasses will still work. If set for distance the lenses may be a bit thinner, but that is about the only difference.

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      For this reason I think a reasonable strategy with monofocal lenses is to set one to leave you slightly near sighted at -1.5 D, and the other corrected fully for distance. This way you will likely have very good vision without glasses, and even better with glasses as a backup. And since monofocal lenses are used for each eye there is no extra cost.

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      I have been near sighted all my life and I sure have no trouble adjusting to having one eye full corrected and the other slightly myopic. I am loving being eyeglasses free. I have some progressives but I almost never use them.

    • Posted

      I called my surgeon's office and was told they only use IOLMaster for eye measurements. For those having a dense cataract, they would send them to a hospital for ultrasonic scans.

      I told my surgeon I would go with Clareon for the first eye and then wait for eight weeks for the second one. Now I am a little worried about positive dysphotopsia that many Alcon IOLs users have complained about. Very frustrating.

    • Posted

      I am not aware of many having positive dysphotopsia in plain monofocals. That said I do have some positive dysphotosia in my first eye which has a AcrySof IQ monofocal. About 10 months after surgery I got a PVD (Posterior Vitreous Detachment). It looks a bit like a fuzzy spider that hangs around in my peripheral vision. It has nothing to do with the IOL, and is primarily an age induced thing. However, the statistics show the odds of it happening are increased by cataract surgery. In any case at the same time I started to see this flash of like, like a shooting star down the temple side of my eye, but only in dark places where there is a point source of light off to my left. I think it is a reflection off the edge of my IOL. But it rarely happens and is more of a surprise thing than any impairment of my vision. I am almost a year after having the second lens, a Clareon, and have not had the PVD or the shooting star effect yet -- fingers crossed.

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