Month: December 2014

Thoughts on No-Touch-Prk modes on some lasers

i used to use MMC for Rx above -5, then had some late (>3 mo out) haze for -4, and rarely had it for -3 something

so i reduced my limit for MMC (since it is really perfectly safe if diluted properly and applied on a sponge) to > -3
this depends where you are, like if in an area with more sun/UV/wind/etc scarring is more likely, so need MMC more
i tried through epi PRK years ago, i’m on a VISX, there is an (old) software setting for this (“laser-scrape”)
the reason we called it “laser scrape” is that you always get a ring of residual epithelium that you then need to scrape off
which defeats the purpose of using the laser to remove the epi (over Amoilis brush) to make it less traumatic/cleaner
the reason again for this optically is the laser becomes more tangential/less orthogonal to the cornea towards the periphery
so the efficiency is decreased, so you get central breakthrough before the periphery
i understand that modern software algorithms add energy to the periphery to try to obtain uniform epi removal/breakthrough
however, there still aren’t great methods that are always used to measure preop epi thickness (preop OCT isn’t common)
so then we are reduced to visualizing removal by looking for visual breakthrough
i also think that the energy of the eximer on the epi is probably imparted somewhat onto the underlying cornea
so that you are probably adding energy/trauma to the underlying cornea while you are doing a laser epi removal
which is another reason why you might want to use MMC for -3, especially if you are emplying laser-scrape
so my suggestion based on the above to avoid haze in future cases would be to:
1. prechill the cornea with frozen BSS preop
2. apply chilled BSS on a sponge after epi removal and before corneal ablation
3. add MMC after ablation
4. add oral steroids postop + Vit C + UV protection
fundamentally, i have had excellent results after EtOH-assisted PRK/LASEK, so don’t know why you need to laser scrape
what is the rationale for using laser-scrape over EtOH-assisted epi removal?
it seems to me that the latter is actually less traumatic, and less prone to scarring (at least in my hands)
although the patients do seem to like the sound of “no-touch/all-laser” from a marketing perspective
eager to hear your thoughts

Dr. Chynn on same day bilateral cataract surgery

Was a bit surprised that OMIC has granted liability coverage for same day bilateral cataract surgery. They have suggestions but not underwriter requirements/ restrictions. Certainly a refusal to cover this could have discouraged ophthalmology from going further in that direction. I know same day cataract surgery has been discussed on keranet with proponents for it. I guess all the OMIC insured ultimately take the pooled financial risk of this. Certainly hope OMIC has thought this through and feels that a case of bilateral endophthalmitis secondary to an elective surgery is defensible…..
I know this may not exactly help in a court of law, like if you were sued for a bilat complication from doing bilat CE

I personally would not do that, as the worst-case scenario of bilat endophtalmitis is so bad
However, i did my cornea fellowship under Doyle Stulting, Past President of ASCRS, who is a MD and PhD so very precise
I remember when i did this fellowship in the early days of laser vision correction (1996), we were just transitioning from unilat to bilat refractive surgery, so we had the same question of whether or not we should do bilat surgery
Well, Doyle is one of the most meticulously quantitative doctors whom i have ever met, and while my refractive fellowship preceptor (George Waring) was too, we were debating this issue in a somewhat qualitative way, and also leaving out other important considerations (because they were not eye-related)
Doyle asked one of the outgoing fellows (?maybe Keith Walter?) to help calculate the risk of being severely injured or killed in a car accident on the drive to and from Emory Eye Clinic, taking into account such factors as the average length of commute (quite far for our catchment area), and the average fatality rate on Georgia highways using public data, and they actually concluded that the “risk savings” that you would gain from doing LASIK on different days was more than counterbalanced by the additional risk you would have from doubling the number of commutes in and out for op and postops!:)
there is also the consideration from a statistical POV that, although you are taking the risk of a bilat complication down to almost zero by doing the 2 eyes on different days, you are in some ways doubling the risk of having a complication in 1 eye (because you are undergoing 2 procedures, not 1). this is analogous to very conservative parents who take separate planes when flying when they have young children, while they are basically taking the risk of them both dying and leaving their kids orphans and putting it down to zero, what they often don’t think about is that they are also effectively doubling the chance that 1 of them will die in a plane crash (bc they are now taking 2 flights, not 1)
so those are 2 logical arguments that are quantitative and may be used in a court of law. more practically, i do use these when discussing the pros and cons of doing bilat LASEK surgery with patients (along with the concept that if you do unilat surgery you can use data from over/undercorrections to try to prevent that in the 2nd eye)
i don’t know exactly what the odds are of bad complications for refractive surgery vs modern CE, but again, am unscientifically shying away from bilat CE, just bc the downside of an infection after CE is usually worse than after refractive surgery, particularly surface ablation (bc it’s easier to treat surface infections than those underneath a flap)
hope this helps

Dr. Chynn on besivance


Anyone had issues with poor epithelial healing (or even corneal melts) with Besivance?
I’ve heard of this but think it’s BS because I’ve done literally 1,900 LASEKs using Besivance so if there was a true association I’d notice it by now as melts would be more common in ASA than in LASIK
The only thing that makes sense is you shouldn’t apply it under the BCL after LASIK BC it’s so lubricating BC of vehicle that it causes flap slippage. Even that’s not a problem if you apply it on top of the BCL
I have taken care of two patients s/p PRK who had severely delayed epithelial healing with consequent haze and loss of BSCVA.  Both patients were on Besivance and healed within four days once the Besivance was stopped.  Both required retreatment.  I do not use Besivance in the presence of an epi defect regardless of etiology.  I believe ASCRS issued a warning about Besivance and other meds that were implicated in a delay of healing.
With all due respect I think the warning is BS
I’m performing about 1000 ASAs per year. So my yearly experience exceeds the entire lifetime experience of the MDs who issued that warning
If Besivance caused delayed reepithelialization I’d have noticed that when I switched from another fluroquinolone in the 1-eyed trial I conducted with my fellows before we deemed it safe enough to switch
Please forgive me for not taking 100 hrs to publish that as I don’t have a base income provided by an academic position or consulting retainers"</p

Dr. Chynn on NSAID effects on overcorrections post PRK

Comment from another MD

Evan’s post  was asking “anyone had issues with poor epithelial healing (or even corneal melting) with Besivance”.  My response is based on my clinical referral practice and the attached document.

Please note this section from the attached document:

These medications contain vehicles that have the potential to be sequestered beneath a LASIK flap or a bandage contact lens following PRK and not absorbed.  The ASCRS Cornea and Refractive Surgery Clinical Committees have become aware of several cases of flap slippage and/or diffuse lamellar keratitis (DLK) following LASIK when topical ophthalmic medications with these advanced vehicles have been instilled immediately prior to LASIK or intraoperatively while the flap has been elevated.  There have been no problems documented with the use of these medications after the flap has been properly positioned.  There have also been documented cases of poor epithelial healing when topical ophthalmic medications with these advanced vehicles have been instilled on the stromal bed following PRK prior to placement of a bandage contact lens. 

I have bolded the section that was relevant to my post.  Emil, I think there may a significant difference in wound healing between LASEK and the epi defect in PRK.  In any event, I do not use Besivance in the presence of an epithelial defect.


Dr. Chynn’s answer

There’s no difference, because I’m no longer putting flaps back. So what I’m calling a LASEK others might call an alcohol-assisted PRK
In my humble opinion, after having performed more surface ablations than anyone else on this forum, it’s not “cautious” to advise people not to use Besivance after PRK. It’s bad advice, BC as long as you stick the drop ON TOP OF the BCL rather than UNDER it there’s no delayed healing. Period!
Or would you say I need to do 3,000 ASAs w Besivance before I’m sure about this point?
What evidence does anyone have of delayed healing after PRK when you stick B properly on top of the BCL rather than improperly below it?
Seems like none
So how’s it scientific to recommend against something when you have 0 cases demonstrating your “point of view” and I have 2000 cases demonstrating that it is safe when properly dosed and applied?
Same problem of over-generalization that “NSAIDs can cause corneal melts so bad they might lead to perforation”
That problem was probably due to a particular brand of generic NSAID, probably the carrier/vehicle, that was quickly removed from the market
Now because of this bad over-generalization people are scared of QID dosing of NSAIDs for more than a week
Well, I’ve dosed NSAIDs at QID for MONTHS post ASA to regress HUNDREDS of over corrections, and that does work, can cause permanent epithelial hyperplasia (or more properly hyperplasia to a normal thickness as “over-responders” after ASA are probably “under-healers” who’s epithelium grows back thinner than normal). So you can get rid of up to +1D wo further surgery"</p


Dr. Chynn’s comments on CXL


Not sure if this topic has already been discussed (and if so, can somebody please forward me the conclusion of that discussion?)
If you receive a post LASIK Ectasia in one eye after bilateral LASIK treatment, would you do CXL only in the affected eye or would you do it “prophylactically” also in the unaffected eye, assuming that the “unknown” ectatic factor might be present in both eyes and hasn’t manifested yet (or never will…)
Let me know what you think.
i think bc kc is often highly asssymetric (so it appears unilateral, but may in fact be bilateral), it’s probably safer to do CXL in the other eye, especially since the downside to doing so is very low

for that same reason, it is probably more medically and legally defensible doing an ASA/LASEK/epiLASEK on the fellow eye (although in canada you’ve not had the multi-million dollar jury awards for post-LASIK ectasia that have become frequent in the US)
i do some medial malpractive review, and want to point out that you need 3 things to lose medical malpractice in the US:
1. negligence (= departure from care, meaning from the community standards/what a reasonable practitioner would do)
2. causation
3. damages
therefore, if you do a LASIK in the other eye and he gets KC, a JD can easily find some MD who said you did wrong
hence you might be screwed on 1
and on 2 and 3 also (so you might lose)
if you, in contrast, did a CXL + LASEK on the fellow eye, the JD might have a hard time getting a MD to say 1 was off
so then even if 2 and 3 exist, you get off the hook (since you need 1 + 2 + 3 to lose, ie all 3 of 3 are necessary to lose)
i don’t know about the canadian system specifically, but i would imagine it is pretty similar to the US system
but in any case, this is the way the US system works, which might be somewhat illuminating to the younger MDs on Knet
hope this helps, and stay out of trouble!:)

Dr. Chynn’s comments on eye drop regime


There being no hard evidence that postop antibiotics reduce the incidence of endophthalmitis, we do this because it makes some logical sense, and if challenged we can say we did “something” to prevent endophthalmitis postop. But, we could also make a defensible argument that they are not necessary. That said, there is no “perfect” prophylactic drug, because there is no drug that you can count on to kill EVERY organism every time, so you have to pick your poison, so to speak, and I think you could defend the use of virtually any broad-spectrum antibiotic, whether it be a fluoroquinolone, Polytrim, aminoglycoside, or perhaps even a macrolide. Given that, by far, the predominance of organisms causing endophthalmitis are staph, either coag-positive or -negative, and the high percentage that have become methicillin resistant, and the high level of resistance to FQs of those organisms, and the better effectiveness of trimethoprim against those organisms, I think that you could make a compelling argument that polymixin (which kills virtually every gram-negative except Proteus) combined with trimethoprim (which has good gram-positive coverage and better than FQs against MRSA or MRSE), that Polytrim is, in fact, a PREFERRED medication for postop prophylaxis. So yes, I think it is well within the standard of care, and, if necessary, I would come to court with you to defend that point of view.


Our standard dosing post ASA is Besivance BID and a steroid QD. This regime allows 90% of our patients to reepithelialize in a few days with zero pain. Also using oral steroids eg medrol dosepak which allows you to dose topical steroid QD n also decreases pain

Commenting on an article by another doctor


I have been asked to defend the ophthalmic surgeons request to use multidose eye drops for dilating patients in pre op prior to ophthalmic surgery
Our pharmacy and risk management  leaders are against this despite the recent and seemingly never ending shortage and high cost of single use drops
Please see article enclosed
What are your thoughts ?
Is there such an overwhelming risk by using mydriacyl phenylephrine and cyclogyl in a standard 5 ml bottle used just for the one day ?
Meeting is at 6 tomorrow morning
Many thanks

A by Dr. Emil W. Chynn:

It’s a bad paper for many reasons:
The eye and skin aren’t sterile
The bugs they grew out are normal flora
You put the drops in before prepping
They failed to show any transmission
They failed to show any disease causation
In 90% of countries they use multi dose drops preop wo problems. Usually over many days
So using multi dose within a day then discarding is perfectly reasonable n logical

– See more at:

Dr. Chynn on SMILE procedure

A college of Dr. Chynn inquired about the new SMILE ReLEX procedure


I have a friend in London with myopia (-1.75 & -2.75, Aet ~ 40 & female) considering refractive surgery.
Is it time for SMILE (1,2) or if it were your family member would you do LASIK … or PRK?
Any recommendations re surgeon – please contact me directly.
Is there really less dry eye (3)?
A by Emil Chynn, MD:
My humble yet informed opinion as the 1st eye MD in NYC to get LASIK and having switched from incisional to non incisional surgery years ago:
at such a low rx, she should have LASEK, as there is 0 risk of making her see worse in well-trained hands, and there is no need to cut a flap for such a low Rx, and her chance of haze at such a low Rx is also 0, and she will heal quickly if it is a true LASEK not a PRK (defined as en bloc removal of epithelium, not whether you put it back or not, i suggest not after 20,000 surface ablations), and he chance of dry eyes or night glare will be lower than after any incisional surgery, and i don’t know why smile is all the rage except for marketing, having seen many and done 1 while in europe last year, and you cannot treat HOA or even cyl very well with smile, so isn’t it really a glorified ALK?

A doctor had post-LASIK complications here is Dr. Chynn’s answer


I would be most thankful if you could give me your precious input in this case. The 35 yo patient had a LASIK in both eyes 8 months ago, in her 1st post op day, she had both eyes dislocated flaps and epithelial ingrowth after that.

However, the bilateral weird lesions were found in addition to the epithelial ingrowth. There is no eye inflamation, no complaints at all, no soreness and even the V/A is 6/5 with prescription. Is this an infections crystalline keratopathy (ICK)?
There is an indolent course and in stereoscopic view, looks like a cyst under the flaps with some cristal like shape material inside.
Please, find the picture from both eyes attached. I look forward to receiving your opinion!
Thank you.
A by Emil Chynn, MD:
i would do this myself:

1. lift up flap very atraumatically
2. scrape very aggressively, both the bed and undersurface of the flap, need a lot of pressure or won’t remove the tissue
3. when you scrape the underside of the flap it helps to put something underneath or the flap will slide around and you will unintentionally debride all the epithelium which would again predispose to epi ingrowth
4. apply alcohol afterwards to kill off the many epi cells you aren’t going to be able to scrape off
5. may need to apply hypotonic saline to swell up the flap as a good scraping takes several minutes, during which time the flap dehydrates, and if that happens too much you’ll get a mismatch between flap and bed, which would again predispose to epi ingrowth. an additional benefit is the hypotonic saline will remove any striae that might be present (which is common)
6. stretch flap out so you don’t have flap/bed size mismatch
7. put in sutures where the epi ingrowth was, don’t tie too tight or will induce a lot of astigmatism, but tight enough that it secures the edge to prevent recurrance, what i like to do is tie them a bit tight to induce a tiny bit of cyl, which then mostly goes away when you later cut the sutures, i usually use interrrupted bc that is a LOT easier than running, but i have seen excellent and possibly more astimatically-neutral running sutures by surgeons who might be more dextrous than myself;)
and, my final plug for my sub-sub-specialty:
hope this helps and good luck

Dr. Elghobaier, former fellow

Working with Dr. Chynn as a refractive fellow at PAL is a great experience I will never forget. It’s very hard to summarise all what I gained in such few words. At PAL all staff are multifunction, well trained and continuously educated. Any mistake is analysed in front of all so nothing there is kept for chance.

As a doctor I learned a lot of paramedical and nonmedical stuff such as marketing, administration, dealing with hightech software and hardware and doing simple maintainance of medical machines. One will never find all of this at any other private practice. So I think PAL is the best center to learn any fellow how to manage a private practice in USA particularly Dr. Chynn has no work secrets in front of his fellows and every thing is a subject of extended discussion.
Away from working hours, Dr. Chynn is not that kind of stiff managers but he is a very nice guy. He is a real New Yorker ? He told me about many things in the big city. I still remember our walking from his home to the practice with his nice dog Rhett :) we made ice balls and used high trees as targets :) He won by the way ?

Dr. Mohamed Gamal Elghobaier, medical director of  Oyoun Masr Center for Refractive and ophthalmic surgeries, Sohag, Egypt

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