F.A.O Dr Kutryb & Dr Hagan..limbal calculation

[indi1664]

Hello,
         I have recently had catarct surgery...as previously mentioned I was -20 both eyes

LE  Sph +1.5    Cyl -1.5    Axis 94   (Operation 3 months ago)

RE approx -1 not tested yet

From the above,and previously kindly explained by Dr Kutryb,my LE overeall prescription works out to +0.75....
I was recently informed that with correct limbal incisions...i could acheive -0.5 to -0.75....if this is possible ...I would have perfect vision to my requirement...

Can you please advise what approximate Axis degree correction is required to acheive -0.5...and risk level...of limbal surgery.

Many Thanks

[John C Hagan III, MD, FACS, FAAO]

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[JodieJ]

I don't know anything about the technical aspects of this procedure, but let's assume it's correct.  Unfortunately, Sph +1.5  Cyl -.5  Axis ?? has a spherical equivalent of +1.25.  You are currently +.75.  A little astigmatism isn't a bad thing when you are farsighted.

Are you able to wear a toric contact lens?  This could correct your LE vision to plano.  With your right eye at about -1.0, you'd have a very nice range of vision.

[indi1664]

Hsi,
     Sry havent replied earlier....Many Many Thanks ...for your replies...this is a ifficult area to fully understand.

I was informed with my LE  Sph +1.5    Cyl -1.5    Axis 94....if the Axis was corrected to approx 4 degrees of centre and and 2 minor incisions of about 2-3 mm above and below the central area ....I could acheive correction to -0.5 to -0.75...IS THIS CORRECT..if so...would than give me a very good overall outcome.....this is my major concern...

Rgds

Indi

[John C Hagan III, MD, FACS, FAAO]

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[JodieJ]

Spherical equivalents are really just an estimate.  At -.50D with one diopter of astigmatism, I believe that your spherical equivalent would be -1D.  (Uncorrected astigmatism pulls vision in the myopic direction.  If you had only .50D of astigmatism, your spherical equivalent would be -.75D.)  Having 20/25 distance vision is very good, and you can probably see your monitor without straining.  I'm jealous.

[JodieJ]

I think that having good vision depends on a lot of factors, including contrast sensitivity and the ability to use both eyes together.  It's a lot more than just the ability to read lines on an eye chart.  Regarding the concept of "spherical equivaIent," I read somewhere that the axis of astigmatism makes a difference in the ability to read the letters on a chart.  (I suppose that the direction of the blur affects a person's ability to distinguish between letters.)  One of my eyes is +.25D with .50D of astigmatism, and I can easily read the 20/20 line.  But my vision would probably be slightly sharper at plano with no astigmatism.

[John C Hagan III, MD, FACS, FAAO]

0.50 diopters of astigmatism is not enough to justify a LRI or a toric IOL. By placing the surgical incision over the astigmatic axis and making it sl larger than normal and using more steroids than normal a half diopter of astigmatism can be easily corrected.

JCH MD

[2ndsight]

Jodie it strikes me reading these posts by Capes and indi that maybe there is some confusion about "spherical equivalent" and actual vision.

for example as I stated in my post to Capes55, I was corrected to -.50 and I have 1 diopter of astigmatism so my spherical equivalent is possibly plano, but that does NOT mean I can see absolutely perfectly, I still see 20/25 on the eye chart and have the visual affects of the astigmatism at all distances.

Maybe you or Dr Hagan should clarify this. It's possible people reading these posts will go to their doctors expecting to achieve something with spherical equivalent which does not translate into 20/20 vision.

[JodieJ]

Coming from a non-eye care professional, my advice would be not to have limbal relaxing incisions.  With only .5D of astigmatism, your spherical equivalent would be +1.25D (as opposed to your current +.75D).  I tried to explain why in recent posts to Capes55 but didn't do a great job.  

I know that your near/intermediate vision is very blurry at +.75D, but it's pretty blurry at plano, too.  Both of my eyes are at plano, and I wear progressive glasses or bifocal contacts just about all the time.  You could see what plano is like with a toric contact lens; it would improve your distance vision.