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Any difference of Residual Astigmatism and irregular Astigmatism

Dr Oyakawa:
A follow up with the discussion of irregular astigmatism.
I went to an eye doctor to ask for a referral to another cataract surgeon.
He told me the similar things you told me - he doesn't believe a pin-hole 20/25 against my glasses vision of 20/50.
He advises me my vision may not be up to 20/25 even with the cataract removal as I am likely to have residual astigmatism afterwards. He doesn't have a corneal topograph machine nor a hard contact lens.

Is there any difference between irregular and residual astigmatism ?
More important, does the pin-hole normally under-estimate or over-estimate the post-operation vision (at my range of vision) ? This really affects my decision to go for a cataract surgery or not. Is jumping from 20/50 to 20/25 means a lot for a cataract surgery ?

Thanks

Thanks
Best Answer
711220 tn?1251891127
MEDICAL PROFESSIONAL
You previous post did not mention astigmatism.  Is the 20/50 with the two diopter of astigmatism?

If there is some irregular astigmatism then you will mostly likely not achieve the best corrected vision.

Residual astigmatism is the amount of astigmatism remaining after an attempt to correct astigmatism with Laser,  LRI, or a toric.  It is not the same as irregular astigmatism.

Dr. O.






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Avatar universal
Just want to add more info.
I don't have Lasik or any other surgery before except the RD surgery in my left eye. Not sure if the buckle can cause irregular astigmatism.
As I mentioned before, when viewing distant objects more than 30 ft like signs in shopping mall, my left eye has double vision (sometimes even 3 to 4 shadows with the same letter if the distance is more than 100 ft) even with my glasses. Not sure is it caused by the cataract.

Thanks
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Avatar universal
Dr Oyakawa,
Sorry I forget put that in my previous post.
My 20/50 is tested with a glasses to correct my astigmatism with magnitude of  2 diopter and 180 deg. This is the prescription before my RD surgery and the optometrist cannot find any difference in astigmatism after the RD surgery. Of course, I don't rule out the possibility that this measurement is not accurate.

If there is irregular astigmatism, can it be reduced during the cataract surgery.
Thanks


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Avatar universal
Sorry, just to want know the convention in eye care world.
Is residual astigmatism the same as irregular astigmatism ?

thanks
Helpful - 0
Avatar universal
Dr Oyakawa,
My glasses does have astigmatic correction (around 2.0D at 180 deg). I am going to see a cataract surgeon with a first consultation and hopefully there will be a test using the corneal topograph machine.
If it is confirmed that there is irregular astigmatism, does it imply the pin-hole result (20/25) will over-estimate my post-operation vision.

thanks
Helpful - 0
711220 tn?1251891127
MEDICAL PROFESSIONAL
You have to determine your best corrected vision.  It does not make sense that you do not have some astigmatic correction in you glasses if the pinhole makes a significant difference.  However,  a pinhole vision can not differentiate regular from irregular astigmatism.  No astigmatism is like a volley ball.  Astigmatism is like a football.  The two radii of curves is constant and can be corrected by glasses.   Irregular astigmatism is like a distorted football and can not be corrected by glasses.  A hard contact lens makes an irregular surface smooth.


You really need to find a doctor who can do a complete examination and does surgery.


Dr. O.
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