 Thank you very much for that very interesting discussion. So next we have Dr. Wang who will be discussing a case of epithelial ingroth. Thank you so much for the opportunity to present today. So today I wanted to present a patient of Dr. Linz who came to us with a challenging case of epithelial ingroth. So this was a 41-year-old female who had Lasik in both eyes in 1999 with a microcaratome and then had Lasik retreatment in 2011 in both eyes with epithelial ingroth in both eyes after that retreatment. She had actually already gotten two flap relifts in both eyes combined with retreatment and some type of glue per her history. Her left eye was not bothering her, it corrected to 2020, but the right eye was really the most bothersome to her. She only corrected to about 2040 and she also described her vision as very distorted. And as you can see here there are four very prominent areas of epithelial ingroth underneath her flap. So in face with this patient I had a few questions. First is what is epithelial ingroth? Second is how common is epithelial ingroth and what are the risk factors for its development? And finally what are the treatment options? So let's go over the first question which is what is epithelial ingroth? So epithelial ingroth as it sounds like is epithelium growing where it should not be. It actually wasn't first described with Lasik, it was first described with glaucoma surgeries and extra caps. And we actually have pathology from some of these patients. So this was an interesting case of a 77-year-old man who received extra cap surgery in 1977 and then had a gray membrane grow over the endothelium of superior cornea and also over some of the anterior segment structures. And what the surgeons elected to do in this case was actually treat him by sizing his iris, ciliary body cornea and limbis with a corneal transplant, hence why we have pathology. Here you can see a photograph and the black arrowheads are pointing to that gray sheet of cells. And here's the pathology. So super interesting, you can see the epithelial cells actually growing over decimates membrane DM and the corneal endothelium CE. CS indicates corneal stroma. Now after the advent of Lasik, there were started becoming case reports of epithelial enggrowth in Lasik flaps. And we actually have pathology from some of these samples as well. And that is because in this case at least we have a 37-year-old man with keratoconus who in 1985 had received PKP but then received Lasik over that PKP for anisomotropia. There was difficulty with suction during the case and a free flap was created with a microkeratone. And he subsequently developed epithelial enggrowth in that Lasik flap. And then received a repeat PKP. So here you see on the pathology slides sheets of cystic epithelial cells that actually connect with the flap edge. And the authors proposed that there were two main theories of epithelial enggrowth. The first, which was much less common and much less aggressive, is epithelial cells, which kind of originate from epithelial cells that are dragged underneath the flap during the Lasik flap creation or maybe not irrigated out well enough. But they're isolated cells that resolve with time and are typically not aggressive. But the more concerning type was epithelial enggrowth that connects to the flap edge close to stem cells and continues to proliferate and is much more aggressive as in our patient's case. So how common is epithelial enggrowth and what are the risk factors for its development? So the first large manuscript that I found detailing the rates of epithelial enggrowth was actually published in 2000. And this was a retrospective case, large case series of over 3,000 patients who received Lasik, 480 of them who received retreatment between 1996 to 1998 in one center. These patients were treated for myopic Lasik only and received microcaratome Lasik. And there were 43 eyes total out of this number that had epithelial enggrowth. And this paper identified several risk factors including having an epithelial defect at the time of flap creation or EBMD. Now the authors in this paper argue that not all epithelial enggrowth needs to be treated. It's very peripheral, not bothering the patient, not progressive, but that there are certain characteristics that make it more necessary to treat epithelial enggrowth. For example, if it encroaches upon the pupil's center causing glare and other visual disturbances, if it actually lifts up the flap edge causing flourishing pooling in a constant foreign body sensation, if it raises up the flap enough to cause a regular astigmatism, or in the worst case, if it actually causes flap melting or keratolysis. Now this was actually a recent review published in 2018 that reviewed all the literature thus far detailing risk factors for epithelial enggrowth following Lasik. And the authors found in the literature many risk factors described including, for example, a microcaratome Lasik flap over a femtosecond Lasik flap because of the way that the flap is created, or for example the Lasik flap dislocating. I found interesting hyperopic Lasik over myopic Lasik or needing a flap lift for retreatment. And in terms of our patient recall, she had a microcaratome Lasik so she definitely has one of these risk factors and she also had had actually multiple flap lifts during her treatment course. So now what are treatment options? So that same manuscript actually described a bunch of different treatment options that are in the literature all are kind of retrospective case series. MD stands for mechanical debridement. So you have mechanical debridement only, mechanical debridement plus some type of alcohol solution, mechanical debridement plus glue, or maybe plus mitomycin C or plus fibrin sealant or some type of other glue. Even amniotic membrane graphs or PTK or actually YAG laser. And what I found most interesting about this is that no matter what the method there is still actually a not insignificant rate of recurrence for many of these patients even after their primary treatment for their epithelium growth. So it's definitely something very difficult to treat. So I want to talk a little bit more about the YAG approach because as you'll see we tried that for our patient as I'll describe. So this is a case report. Panels A and B superior are before and panels A, B, and C inferior are after. And you can see that after the authors used YAG laser on that LASIK flop interface at the area of epithelial cells. There actually was pretty good regression, which was very interesting. So back to our patient. So recall she had LASIK in both eyes in 1999 with retreatment in 2011 and had epithelium growth in both eyes after that retreatment. She had already had a few red flop relifts combined with retreatment and some question of glue. Her left eye was not bothering her and this was her right eye only corrects to 2040 with these nests of epithelial cells and her vision is very distorted. So we actually first did try YAG laser for her and unfortunately it didn't seem to really work in this case. You have before on the left and then one month later on the right and you can see that that area of epithelium growth doesn't seem like it's regressing. So after that was tried she actually underwent it. Flap lift was suturing as she hadn't had that before and glue and a bandage contact lens. So here's a video. So this is lifting the flap and then debriding off those epithelial cells first with a WEX cell then with a grease halber continuing to debride also debriding off the back side of the flap. This was actually done in the OR2 in a more controlled environment not in the Lasik suite. Irrigating profusely, flipping that flap back over, padding it down with a WEX cell, putting sutures in place to make sure the flap stays tucked down, rotating the sutures and then actually putting a wrist shirt and then a contact lens. So this is the patient at post op week one. You can see the sutures in place buried and the edges of the flap were actually not healing very well. So actually at post op week two she had some of that epithelium taken off and the suture is removed and here she is at post op month two. So her vision definitely corrects better. It corrects to 2020 without corrections 2040 and you see that many of the epithelial in growth areas are at least at this point not present but that one portion in one quadrant here in the left bottom corner she does have recurrence of epithelial in growth although it's not connected to the flap edge. So question is what to do for in the future. I think at this point we are going to observe her but there as you can see there are a lot of different options none of which is really necessarily the right answer so curious to hear what your thoughts are. Thank you.