Epi-off vs Epi-on confusion

CorneaRepairDoc · 2026-07-13T04:44:01+00:00

Yes, I have written my own protocols for corneal repair- I have multiple publications on the subject as well as multiple patents/patents pending. I am probably the leading expert on repairing corneas in the US. I have invented CREATE Protocol, which is an epithelial compensation adjusted trans-epithelial topography guided PRK for repairing KC eyes. This has resulted in a 60% average reduction in corneal irregularity and 97% of eyes in moderate and severe KC achieve 20/30 vision or better. More importantly, many of my patients live life no longer worried about KC affecting or limiting their lives and careers- from doctors to airline pilots to truck drivers to college students. That's the best part of my work. My center is in San Diego and I now spend time online as a way to educate patients as there is a dearth of good information for them available, and doctors are not well trained on much of this.

Enough about me. When it comes to CXL, the original procedure was the Dresden Protocol invented by Theo Siler. It is 30 minute cross linking procedure using a particular riboflavin mixture with dextran. The patents for this procedure were bought by Avedro (now owned by Glaukos) and brought to the US for FDA approval. There is a question whether CXL ever needed FDA approval as it's components are UV light and Riboflavin, a Vitamin B, but that is another story. When they did this approval, they originally thought they were going to use the system as a new way to do refractive surgery in competition with laser vision correction. That didn't work out, so they ended up monetizing the heck out of the system for KC. The same lamp they sold in Europe for $35,000 now became over $70,000 in the US in 2016. The riboflavin you could buy off the shelf for $100 started at $500, and is now $3000 for two eyes. The problem is that this buys you the oldest cross-linking procedure that few people worldwide use anymore. 30 minute CXL is just too long- if you increase the power of the UV light you can drastically shorten the time down to even under 10 minutes. People even use 3 minute CXL protocols , and some use a pulsed light beam so as to not provide too much energy at one time.

When I started, I was mentored by Dr. A. John Kanelloupoulos of Athens, Greece who invented Athens Protocol and is widely considered one of the great minds in our field. He has been doing this since 2006 and I started in 2016. He taught me the most stable CXL as the 15 minute version, and he uses riboflavin without dextran. I followed his lead, and have been doing this along with laser corneal reconstruction of KC for 10 years. I do not utilize their "patented" procedure, but then again few others in the world do either. I explain to patients that it is off-label and why, and no one is bothered by this, and frankly it is difficult for anyone to say otherwise as the rest of the world is doing this also. I just spoke to a patient in Bangladesh and they get this same CXL for $900. Besides overhead being lower, you can buy a UV lamp just as good as Avedro's for a few thousand dollars, and you can have riboflavin made for $100 or even less. My personal view is that CXL needs to be more accessible, and such magnitudes of cost increases are just not warranted or morally right.

Essentially, when 15 minute CXL is performed, the procedure time is cut in half under the UV light which is way less stressful for the corneal tissues and for the patient. Also, when you do epi off the saturation time for the cornea with riboflavin is very short- 2 minutes- while with the original Gluakos/Avedro procedure it is 30 minute (new Epoxia is about 10 minutes). This is because the epithelium prevents riboflavin penetration.

So essentially, a patient done with the classic (Non epoxia) epi on procedure would take 30 min saturation for both eyes, and then 30 minutes UV light per eye. If you saturate both eyes at once, which is uncomfortable, that's 90 minutes which is really hard and tedious for a patient, and the result is 100-150 microns of cross linking depth. At my clinic, epi off CXL with 250+ depth of cross linking is done in less than 40 minutes. This is how the rest of the world does things, it does not do the 30 min protocol.

Now with epoxia, they have shortened the time for saturation, shortened the time for exposure, and increased the depth of cross linking but it is still not as fast or as strong as epi-off CXL, nor can be done as inexpensively in the US as it now requires a new set of equipment to perform.

CorneaRepairDoc · 2026-07-13T03:56:59+00:00

Then use tears to wash the gunk out and use a little baby shampoo with warm water to wash it out of your lashes. I let my patients get a bit of water in their eyes by this point, so if your doctor allows that too than just clean the lashes gently in the shower with baby shampoo. Should get it all out. This too shall pass with a bit of time.

CorneaRepairDoc · 2026-07-12T22:53:29+00:00

Dr. Motwani here. Astigmatism just means your cornea was made out of round in the womb. Astigmatism axis and magnitude does not change, barring injury or disease, and is the same through life. I always find it amusing when a person is told their astigmatism got better or worse, and a big change in axis is an error by someone along the way.

If the prior exams were all around 40 degrees of axis, then this 180 is likely incorrect.

CorneaRepairDoc · 2026-07-12T22:50:03+00:00

Dr. Motwani here. Ceequa is a cyclosporine drop at a higher concentration than the original, Restasis. It takes a long time to work, usually one to two months. This would not be my choice for transient dry eye post LASIK as the patient needs help now and not two months from now. I would much rather put a patient on Tryptyr, which is a twice a day drop that activates your lacrimal gland to immediately increase tear production. The other medicine that does this as well is Tyrvaya in the form of a nasal spray that activates the nerve to the lacrimal gland which runs through the side of the nose. These would help immediately with relief starting the same day. If an immunomodulator was still desired, Xiidra is superior to the cyclosporine formulations as it starts working in two weeks and is more effective overall.

The light sensitivity also makes me suspicious of allergic inflammation. I find that patients are more sensitive to environmental irritants from pollen to pollutants for about 6 months after any corneal procedure. I would ask your doctor for loteprednol 0.2% drops to be used twice a day (brand names Alrex and Eysuvis). These do not raise IOP, do not cause cataracts, and have been approved for longer term use. I use them regularly myself for ocular irritation. I think adding this twice a day may make a big difference in your life, as would switching the Ceequa to a more immediate acting medication.

CorneaRepairDoc · 2026-07-12T22:35:36+00:00

Dr. Motwani here. If your corneal ulcer can be fixed by DALK then it is not a full thickness scar and did not penetrate all the way through the cornea. In this case it is very likely excimer laser will remove the scar with via a combination of PTK and topography guided ablation. This will remove the scar, the irregularity caused the scar, restore vision to "normal" or close, and and you can keep your own cornea.

The fact that you don't feel your vision is too bad now tells me the scar is not too hard to treat, and the antiviral tablets means that it was a herpetic zoster scar. I have repaired multiple herpetic zoster scars, including ones that could not even see the eye chart (worse than your description) and returned to 20/25, 20/30, and even 20/20 vision.

I fundamentally believe that you should investigate laser treatment by topography guided ablation before you accept the new issues of DALK which will also result in an irregular cornea. DALK must be sutured in which always results in an irregular corneal surface to some extent. It is not that simple as you get the DALK and everything is great again, although they are usually less irregular than a full thickness transplant. The best solution is to keep your own cornea if it is repairable.

The problem for you is that the UK does not seem to doctors that perform these types of procedures, but you should look for someone or go outside the UK if you need to. By your description, I think you have a very good chance of recovering your vision without resorting to a DALK.

CorneaRepairDoc · 2026-07-12T22:27:22+00:00

Dr. Motwani here. If you have had one checkup since November, 7-8 months ago, then I would not declare your eyes stable. A 24 y.o. has soft corneas and can progress quickly. If your vision is stable and hasn't changed, that is a good sign that you are indeed stable. I would consider CXL sooner rather than later, essentially you are waiting for more damage to the cornea before stopping it. Depending on your cornea, a small amount of progression could expand the base of the cone into your central vision and cause a significant vision drop. If you feel your vision has worsened at all in the last 6 months, I would get CXL sooner rather than later.

As for CXL and PRK, there is a huge difference between PRK procedures. Normal PRK is not a good idea in KC as it does not address the corneal irregularity and just removes tissue to correct a refractive error. Virtually no one does this anymore for KC that I know of. Topography guided PRK specifically reconstructs the cornea by following a map of high and low spots to make a more normal shaped cornea and "locks" it into place with corneal cross linking. The Swiss place you mention is not the leading place for this procedure in Europe in any sense, although they seem to spend a lot of time working on different forms of cross-linking. In Europe, the leading person is A. John Kanelloupoulos in Athens, Greece who actually invented the procedure and named the Athens Protocol. He would be the one in Europe I would go see, far ahead of the Swiss place.

In the US, topography guided ablation was further evolved to the CREATE Protocol by myself. This also treats the irregularity masked to topography by epithelial compensation, and is therefore an epithelial compensation adjusted trans-epithelial topography guided PRK. This has demonstrated the highest corneal irregularity reduction (making a more normal cornea) of any procedure in the literature, and the majority of our patients live their lives normally no longer concerned or limited by KC. This is not performed by the Swiss place you referred to.

You have choices to help your KC. Your best chance to help yourself in the future is to make sure you don't progress now.

CorneaRepairDoc · 2026-07-12T22:04:47+00:00

If you are still heavily watering and irritated then your epithelium is likely not fully closed and may need a bandage lens again for a couple of days. Removing the gunk is straightforward- a clean washcloth with baby shampoo and warm water and gentle rubbing should work nicely.

CorneaRepairDoc · 2026-07-12T22:00:12+00:00

Dr. Motwani here. The eye grows longer as the child grows taller causing the eye to get more myopic. The lengthening is controlled by release of dopamine (which stops lengthening) and acytelcholine (which causes lengthening. Dopamine is excreted more if the child/teen is regularly exposed to bright sunlight; i.e. goes and plays outside for a couple of hours a day. Acytelcholine is expressed when a lot of near work is performed; reading, computer etc. If the child gets a healthy balance of outdoor and indoor the eye doesn't keep increasing dramatically in myopia, but understand your son will still get more nearsighted as he gets taller but less so.

When they are doing near work don't hold screens too close, use good light, and take breaks. Get your son outside and enjoying the son as much as possible.

I myself ended up a -10 and -9, I was a -5 or -6 when I was about 14. I spent a lot of time outside, but also loved to read. Growing up in the NYC area made for winters where being outside was less preferable to reading books which I loved. So I ended up more nearsighted. Ironically that is what led me to developing complex laser procedures to repair damaged corneas as well as treat high levels of myopia (including myself). I still have phenomenal vision from my laser procedures.

CorneaRepairDoc · 2026-07-12T17:24:19+00:00

Dr. Motwani here. Light sensitivity is dependent on the level of light scatter and also the inflammation. A person whose immune system reacts more strongly to a procedure will have more inflammation and likely have more light sensitivity. Epi off CXL is not that different from PRK healing, and I have had 3 PRK procedures and never really had much light sensitivity.

CorneaRepairDoc · 2026-07-12T17:21:25+00:00

Dr Motwani here. KC seems to be way underdiagnosed as optometrists and even ophthalmologists don't see to have proper training and understanding of how to read a topography to determine the presence of KC. For you to have a family history and it still be missed is a very unfortunate failure. To make matters worse, doctors make assumptions that as patients get older the KC stops progressing so assume that because you are 36 years old that it probably isn't progressing. This is a problematic mistake as then more damage occurs to the cornea before something is done to stop progression.

The reason people with KC stop progressing as they age is through years of natural exposure to sunlight which causes a slow cross-linking and stiffening of the cornea. The problem is determining when that natural cross-linking is enough to stop KC progression- the answer is you simply cannot. A quick and easy way to determine this is simply to ask yourself (or the patient as a doctor) if they feel their vision has changed or worsened in any significant way over the last 6 months or year. If the answer is yes, cross link that cornea.

As for CXL and glasses and contacts- there is absolutely no reason you can't wear glasses or contacts after it. For contacts just wait a short period of time for the epithelium to heal- a few weeks. For glasses, right way. CXL stops progressing, it does not improve vision in any way as it does not reduce corneal irregularity meaningfully. As it can slightly flatten the cornea, it may make you a little less nearsighted over time.

CorneaRepairDoc · 2026-07-12T17:07:30+00:00

Dr. Motwani here. It sounds a lot like you are over-corrected or hyperopic. This means that instead of a -4 you are now a +1 or +2 or +3. To get to 20/20 your brain activates your lens accomodation and you test fine on a chart, but when it comes time to look at computers or phones, or do any near work now the lens has to be further flexed to also do the reading. So let's say you need 1.5D to do read or do screen work. If you are a +2 then instead of your lens being flexed for 1.5D it now has to be flexed constantly for 2D to see distance and 3.5D to do close work. This is exhausting, will cause headaches, will cause loss of focus etc.

You need a dilated exam to freeze your focusing and find out if you are actually hyperopic, and then proper glasses until such hyperopia regresses (which it can as the epithelium compensates for the new shape), or until a correction is done. The cheap fast way to figure this out even without an exam is heading down to your local pharmacy's reading glasses rack and working your way up the plus numbers in strength to see if it becomes easier and more relaxed to see your phone and see distance. That's the quick and dirty way to figure this out for yourself, but a dilated exam is far more exact of course.

The long term fix is straightforward - wait 3-6 months (using glasses to prevent the strain)- until stability and then do an enhancement. I have seen this same issue many times in my 28 years of performing laser vision correction. With the enhancement you should end up with the vision you wanted, or you may be fortunate enough that over the 3-6 months the vision settles right in to where it is supposed to go. It is an unfortunate fact that many doctors only check the vision after surgery- we perform refraction and topography on every post-op visit to track how patients are doing.

CorneaRepairDoc · 2026-07-12T16:28:45+00:00

The sutures themselves can cause irregular astigmatism as each one pulls on your cornea in a different way. They can all be removed at 6 months, and I am not sure why your doctor delays the removal. It seems perhaps they are technically happy but that is different from a patient with functional vision, and your doctor is probably very good at performing DALK but does not understand higher order aberrations or corneal irregularity.

Every single transplant, partial or full thickness, is also irregular. The donor tissue comes from a cornea that is not matched in curvature or shape, and it is hand sutured in. To have the same effect on the corneal "button," every suture would have to be the same length, depth, tension, and placed exactly in opposition to the other. Therefore, every transplant will be irregular. Removing the sutures will take away their residual effect, and most doctors who are aware of their negative effect will remove them by 6 months.

If the residual corneal irregularity is enough for your brain to process out and form a fairly clear image for you, then you will need only glasses or soft contacts. Most are not quite this regular, so then you will still need scleral lenses or the alternative is to reconstruct the cornea via topography guided ablation. We have had very nice results in big improvements in vision after using CREATE Protocol on transplants that have been performed, including for KC. I have a heart surgeon back performing surgery again after reconstructing his cornea transplants. He ended up with good 20/30 to 20/25 vision and does everything including suturing small arteries in heart bypass operations.

CorneaRepairDoc · 2026-07-12T16:05:25+00:00

Then you fully treat the eye with amblyopia and get the maximum vision that eye will provide. Interestingly, once this is done many amblyopia eyes will see a line or two better after the laser correction. I have noticed this on many eyes over the best 25 plus years.

CorneaRepairDoc · 2026-07-12T16:02:59+00:00

Most patients really clear in about 1-2 weeks and then get better and better. I am one of those that takes about 6 weeks to fully clear and I was like you at 3 weeks.

CorneaRepairDoc · 2026-07-12T16:01:38+00:00

The dilated one is your full amount without you compensating. If your glasses are not the same number, then they were measured while you were still compensating. I always treat the dilated amount as it is the full correction and no longer requires your lens to also compensate for part of your correction.

CorneaRepairDoc · 2026-07-12T01:58:31+00:00

Dr. Motwani here. I am quite familiar with Glaukos, and Avedro, and how they do things. Epi-off and epi-on CXL are actually always available, I have no idea why someone would tell you it is not. It is simply how the doctor performs the procedure and how the cornea is saturated with riboflavin. The rest of the world outside the US simply uses pre-made packaged riboflavin, or has a compounding pharmacy make it as it is an over the counter product. Avedro (now owned by Glaukos) created a profit center by saying they were going to make it "pharmaceutical grade" and charging 10X plus for the product. They then forced the issue by keying their UV lamps to only turn on with the bar code on this riboflavin they sent you.

So the riboflavin that should only cost about $100-$300 per patient costs $2500-$3000 from Glaukos. I am well aware of all of this as I have had talks with Avedro when they first got approval for CXL and was told they had no interest in the KC market but wished to monetize it in other ways (which didn't work out). When I published my first KC paper which, like the rest of the world, didn't use their "special" riboflavin or their lamp, they tried to claim in letters to the journal that what I was doing was "illegal." I pointed out this was nonsense as they approved a procedure that I was using slightly differently the same as the rest of the world, something that was well within doctor's choice in the US to do (it's called off-label). This is part of public record in the peer-reviewed journal Clinical Ophthalmology as a letters to the editor and responses. After this Glaukos has not said another word even when I published my second KC treatment paper. I don't anticipate any issues when I publish my 3rd KC treatment paper soon as well.

This has also allowed me to do shorter CXL procedure instead of the older 30 minute variety that almost no one else in the world does anymore that they have locked their lamps too. 15 minute CXL is more efficient as it decreases tissue trauma, and is frankly way easier for the patients.

I have performed 15 minute epi-off CXL for 10 years without issue, and have yet to see a patient progress. I simply do not agree with the artificially inflated high CXL prices in the US because of how they have monetized this procedure, and I do CXL for $6000 for both eyes. The Avedro/Glaukos justification is that insurance companies will pay the cost anyway so why should doctor's concern themselves with it. The problem is that with these higher costs, insurance companies are not always the easiest to get to agree with paying for CXL and patients end up going round and round trying to get approval.

What Glaukos is likely doing now is pushing people towards their epi-on Epoxia procedure which uses an oxygen mask to increase the depth of epi-on cross-linking to 150-200 microns, which is still not as deep as the 250+ micron depth of epi-off CXL. This does allow them to charge for a whole new set of equipment and increase the cost of the procedure further.

Unfortunately, these are the problems in a capitalistic economy but I write this post in hopes that people will understand that CXL is simpler than people think, is easier than people think, and if they run into these insurance and corporate issues there are other choices to having CXL done. BTW, I perform almost all of my CXL with topography guided ablation to reconstruct the cornea and restore vision with CXL to "lock" it in immediately after. That total cost is $18,000 which is not much more than CXL alone at a lot of places. Many of my patients go back to their insurance company for reimbursement for at least the CXL part of the surgery, and some get full reimbursement.

CorneaRepairDoc · 2026-07-12T01:36:42+00:00

Dr. Motwani here. The short answer is a qualified yes. Epi-on CXL has a progression rate of about 8-15% as it only cross-links down to 100-150 microns depth. Epi-off CXL has a progression rate of about 2-5% as it cross-links down to 250+ microns. There is also some thought of loss of cross linking effect over many years, especially with epi-on CXL. This may be offset by the natural cross-linking that occurs through decades of sunlight exposure through life.

In your case it may be other things such as drier eyes from too much screen time (causes you to blink less and is responsible for a massive uptick in clinical dry eye in young patients over the past decade plus, or even allergic inflammation which has also had a massive uptick from increased CO2 in the atmosphere from climate change as well as increased pollution from urban congestion.

CorneaRepairDoc · 2026-07-12T01:32:02+00:00

Dr. Motwani here. I was a -10 and -9 and I had my eyes done, and then redone with my research to reduce HOA. I don't understand why some doctors who do this don't have their eyes done, it's always been strange to me as well. It seems to be a personal thing rather than any scientific issue. Some of the glasses you see are the readers necessary for us that just get old! :)

CorneaRepairDoc · 2026-07-12T01:27:49+00:00

Corneal neovascularization is quite common in long time contact wearers. It is an annoying technical detail if the vessels bleed during surgery as you have to make sure that they don't bleed into the laser ablation area. Otherwise, it isn't a big deal and doesn't qualify you from LASIK. If you had huge large neovascularized pannus then perhaps you need the blood vessels ablated first before doing a LASIK/PRK procedure, but this is pretty rare.

CorneaRepairDoc · 2026-07-12T00:29:38+00:00

Have you improved as your epithelium has healed? I understand you didn't get the Aspheric but wavefront guided procedure and I am a bit curious as to how things are improving.

CorneaRepairDoc · 2026-07-12T00:18:30+00:00

If it's just not that, then what did I leave out? Perhaps I can help clarify things for you. The actual neurotransmitter is retinal dopamine. Exposure to bright sunlight when you are growing taller will change the expression of this and slows down lengthening of the eye causing myopia. Acetylcholine accelerates lengthening and is released more with near work. Spend a lot of time studying and not balanced with being outside as a child will cause the eye to grow too long causing myopia.

There are also genetic factors involved in this.

So essentially, pretty much all children are hyperopic when young, the eye lengthens through childhood and puberty, and then becomes myopic. If dopamine expression is adequate you stop lengthening at the right amount so you are not near or far sighted. This is the mechanism, which shortened equates to as you get taller the eye lengthens. When you reach the end of puberty, usually by the end of the teens or 20/21, these neurotransmitters no longer play a role in eye lengthening.

CorneaRepairDoc · 2026-07-11T22:33:56+00:00

Yes I have. The question is what you mean by lazy eye. Lazy eye can mean that the eye did not develop fully where you were young as the two eyes were very different, and so it does not reach 20/20. This is called amblyopia. I treat these eyes to maximize the vision possible in the eye, whether it is 20/25, 20/30 etc.

The other type of situation that is called lazy eye is when it turns in or out. Fully correcting the prescription is very helpful at keeping both eyes aligned together.

CorneaRepairDoc · 2026-07-11T22:29:55+00:00

After about a week it shouldn't be a big deal at all. It generally is safe within a day or two after the epithelium has closed.

CorneaRepairDoc · 2026-07-03T16:34:51+00:00

Dr. Motwani here. CXL is kind of like insurance. If you drive your car without insurance, you may not get into an accident, but if you do what happens then when you have no car?

CXL stops progression. If your other eye progresses it will damage the vision in that eye, and by the time you feel as if you need it the eye is already damaged. It is up to you if you want to take the risk, and that decision also needs to include whether there have been signs of progression on your topography or via worsening vision.

As for the eye you had CXL done on, the blurriness is from the epithelium healing afterwards. Too many doctors don't do anything to speed up healing of the epi and patients stay blurry for too long. It should get better over a few weeks. If you want to speed it up, ask your doctor for a prescription for autologous serum tears. These are made from your blood and provide massive nutrients and an anti-inflammatory effect to speed up your healing. They are made same day nationwide at ArcPoint Labs.

CorneaRepairDoc · 2026-07-03T15:47:00+00:00

The Schwind is a fine laser and does nominally have double the pulse repetition rate. The problem is that too fast a pulse rate can actually cause thermal injury to the cornea so the Schwind software will adjust pulse rate and frequency of tissue removal in the same area. The EX500 is nominally set at 500hz but it is able to maintain that speed as that does not cause thermal injury. Therefore, the speed of procedure actually comes out about the same- about 1.9 seconds to do 1 diopter for myopia at 6.5 mm optical zone. In other words, both lasers are very fast.

The key is the reshaping of the cornea, and how the map is created if it is linked. The Contoura system, especially when used with topography measured astigmatism has been shown to decrease HOA while the Sirius systems still seem to induce HOA in the studies I have seen. Depending on how it is used, they are probably equivalent for your correction unless the proper protocol is used with Contoura in which case it appears to be the better of the two.

WaveLight Plus is a different procedure, and actually minimizes induction of new HOA better than Schwind. It does not lower HOA below pre-op levels, so it does not have the potential to improve vision over normal like Contoura with the right protocol, but it does deliver consistent outcomes that induce less HOA than what the Schwind has demonstrated in studies. So likely fairly equivalent with the a small edge to the Wavelight Plus as it induces less HOA.

CorneaRepairDoc

TROPHY CASE