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ASA Retreat

Dear David et al

Sorry for my delay in responding. I’m visiting my girlfriend’s family in a rural part of Bulgaria wo internet – can you believe that?;)

It’s important to always search very carefully for the cause of over and under-corrections, or you won’t really get at the root problem, and might then just be trying to shoot for plano, wo any real understanding of what went wrong

I don’t even let my fellows present cases for enhancement until they can convince me why the over or under correction occurred

An exhaustive breakdown here would take hours and more properly be the basis for a chapter in a book about refractive surgery. Briefly outlined the possible causes are as follows:

1. Not properly taking into account standard regression with your nomogram (which should slightly overcorrect all myopes and more overcorrect all hyperopes bc they regress more). Regression happens early, so you can figure this out by examining the early postop notes for early refractive status

2. Not properly accounting for myopic progression given age in myopes less than 30 yrs old. I just posted on this extensively a week ago so won’t repost. Did want to ask fellow keranauts if and how they’re accounting for this huge factor themselves?

3. Undershoot in retrospect. Choosing a too low number. Sometimes associated w errors like not adjusting CL power upwards properly to be in the spectacle/laser plane. Much more common in hyperopes bc ignored wet MR/AR which revealed the true full plus Rx!!!

4. Overshoot. Often caused by over minusing young myopes in the refraction by not telling them to not choose smaller than darker, not allowing them to say “the same”, not red/greening them, not making them “earn” the next -.25 by actually proving it makes them see better by going down 1 line on the chart, not performing (I think this wild be legally negligent) or ignoring the wet MR/AR. Also not telling them to look far away in the AR and WaveScan to prevent accommodation!

90% of my fellows can’t properly manifest patients and over minus 90% of young myopes. Admittedly, by the time I properly don’t over-minus them, then add minus to account for progression, we are often at a similar number. This is probably why the general ophthalmologist actually gets good long term results in younger myopes!;) But being the stickler I am, especially as a fellowship preceptor, I insist on getting to the right answer the right way!

5. Scarring or haze causing undercorrections

6. A fellow improperly panicking when seeing an Overcorrected Hyperope in the early postop period, switching from steroids to NSAIDs instead of just waiting for regression, and causing an undercorrection (this is another example of a “trial” Jim). Fortunately this only rarely happens

7. Under/over responders. Right #/wrong result. Lazy people ignore the work necessary to eliminate 1-6 above and lump everyone in this category:( These are just people who don’t regress “properly” according to the meaty part of the bell curve we incorporate into our Nomograms. They either under or over hyperplase their epithelium compared to normals. Then you MUST ADJUST YOUR NOMOGRAM the 2nd time to account for this or you’ll bounce around and never hit Plano!!! Because if they underheal/underhyperplase/overrespond the first time, they’ll do so after enhancement too!

8. Unknown. This is the worst category, and freaks me out, since then I have no logical reason to be confident my enhancement will work out. I refer these cases (1% at most) for second opinions. Half of the time someone smarter than me like Eric Donnenfeld and other super-experts who unfortunately don’t have much time to post on knet will figure out a zebra (like not fully covering the ablated cornea w a sponge containing MMC and causing a ring scar in a myope not a hyperope)

But in summary since it’s not your case and you can’t get all the records, I agree with Ronal’s advice (and thanks for the attribution Ronal):

Why not try Voltaren QID x 1-3 months? Although this technique is more effective in the early postop period, since you’re trying to promote normal regression/epithelial hyperplasia

Hope this helps?

PS I’m ccing my fellows so pls save this in the sever under the name “Analysis Before Enhancements” in the folder “Non-OR Protocols” and don’t forget to go over TWO protocols w each other and me EVERY th and Friday!!!;)

Emil William Chynn, MD, FACS, MBA


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