 when I get started. Sure. All right, good morning, everyone. It's about eight o'clock, so I think we'll get started. This morning we have Dr. Hatch speaking to us about thermal wedger section. He's no stranger, I think, to anyone here, but for those who don't know, one of the great things that he does is he wakes up really, really, really early and comes and sees our post-ops with the chiefs at the VA on a totally volunteer basis. And he has always been there when we've asked him to be there, so that's awesome. So Dr. Hatch will take it away. Thank you. Before I begin, I'd like to express my thanks to Randy Miller and Jim Gilman, who have helped in some of the preparation of this. We're very fortunate to have audio-visual geniuses like those guys around to help us. Many thanks to them. What does one do about a keratometer curvature disparity of eight diopters or more? Glasses or contact lenses might provide reasonably good vision, with for less than eight diopters, a cylinder in a significant number of cases, but eyes with eight, 10, 12, 14 diopters, the cylinder correction, are more called for a creative approach in their care. Such cases often exist following keratoplasty with some corneal wood gaping. If the corneal edge is coming together in a little gaping, well, it takes a little gap, you can get a lot of diopters, a cylinder problem, or wound edge sliding, and that occurs if the wound edges are like this and they slide. They don't tend to leak aqueous and get into problems there, but they sure give you a cylinder problem when the edges slide one on another for whatever reason. Also, if a repeat corneal graft is needed, a keratometric corneal cylinder curvature disparity of say four diopters or more might beg for an operative procedure designed to render a post-keratoplasty graph more spherical. So I haven't used this only on patients who've had a previous corneal transplant. I've used it on some other cases with pleasure. In planning a therapeutic approach, let us consider three areas of major interest. By the way, on this post-keratoplasty problem of high cylinder, I talked to Max Vine about that, the great Max Vine of University of California, Orson White was a resident at Cal, so was Dick Aldous, maybe others who were here. But I said, Max, what do you, and by the way, Max used to do, had most of the corneal referrals for corneal transplant at one time long ago from the inter-mountain area, certainly from Utah. I said, Max, what do you do about these high cylinder things? Do you have something special, or do you just take out the tree fine and tree fine and pray? And he sort of leaned toward the ladder. And so it really intrigued me to wanna find out something special. Relaxing incisions help treat somewhat smaller organic astigmatic errors and they cause a flattening of the curvature when placed across the steeper corneal meridian. And just a few weeks ago, Dr. Balambati presented a very nice grand rounds with his cataract surgery and relaxing incisions and some very nice results. So in the smaller amounts, that is certainly an approach one can take for large amounts of astigmatism, some method of resecting a strip of corneal tissue across the flat meridian and suturing it up again results in steeping the cornea at that meridian. Now here's something, we'll get into this a little further and I've talked about this before when I talked about ocean wide, but these techniques obtain a sought after optical result by changing the anterior surface of the aqueous humor lens. Contrary to teachings of school children and ophthalmology residents for centuries, the normal cornea has no optical power. That's stunning to some, but it's true. But it does help to shape the anterior curvature of the aqueous lens and this will be shown on a DVD to come. A diseased cornea such as in keratoconus can have some optical power but the real power lens starts with the aqueous humor lens and some type of surgery that would add to a removed tissue or substance from the cornea can make an optical lens out of the cornea as part of a four part lens but still the major optical power is in the aqueous lens. It is helpful to review the correct principles of the three lens I which we will do in the DVD is taught by our own first professor of ophthalmology at the University of Utah before there was any division of ophthalmology even. So we may understand the problem involved in this situation and the therapeutic approach is available including the rather neglected but much simpler to do thermal wedge procedure which I'll show you, it really works. Professor Orson White on optics is the first portion of this DVD. Some of you may have seen this eight minute segment before but a review will not hurt. Next is a four minute video on surgical wedge resection of the cornea taken from a VCR by Dr. Richard Troutman showing one way to reduce high sigmatism of the aqueous lens. It is the fact that removing a wedge of corneal tissue at the flat corneal meridian whether it's a surgical or thermal wedge that's being resected will result in steepening of the cornea and aqueous curvature at that meridian. And conversely, lengthening the corneal curve in any meridian as with relaxing incisions will flatten the cornea, curvature at that meridian. And the final segment of the DVD is from a movie film some time ago in my operating room showing thermal wedge at penetrating keratoplasty. This is filmed on Super 8 Kodachrome sound film by Don Smith, friend of mine whose camera and tripod were positioned to the side of the patient. There was no through the lens viewing with the video camera at that time. Some of the details appear a bit unique to you so I'm going to tell you about some of the things you see so you won't just be stunned by seeing them but they were common at the time. I see Dr. Taylor smiling because he knows about land and they were really quite non-problematic. Local anesthesia was used by doing retrobovar anesthesia in all the cases except for those done under general and O'Brien-A. Canesia that was just below the zymatic arch, zygomatic arch by feeling for the cornoid process of mandible and then making injection right onto that. Lateral canthotomy was used in most intraocular cases. There's usually loose corneal epithelium on these eyes stored in the moisture chamber and it was quite loose and it was often gently scraped off from the whole eye. Most of the donor corneas were used within 24 hours after harvest with the 48 hour maximum and four old Black's Hill bridal sutures were placed under the superior and inferior rectus bridal sutures. Yes, it was. It stabilized the eye and he'll keep it from moving around. I've never had a problem with that. Now the muscle guys might have seen lots of them somewhere but I never did. I'd never heard of any. It looks on the borderline of barbaric but it really wasn't and it worked. The tree finder to be used to cut the host button was pressed on the somewhat dry host cornea to leave a temporary mark. Just push it down on it and left it marked. We let the epithelium dry a little bit on the host so we had a mark there and then a crescent, rather gentle hill drifts or some hot wire looped cottery marks were made right at those marks over two to three hour clock hours in length. Placed on the host cornea where the tree find mark had been made recently and centered at the flat corneal meridian. And sometimes two cottery crescents were used, one on each side of the flat meridian if the estimated astigmatism was eight diopters or greater. These cottery crescents then become well within the edge of the excise corneal button. They cause some shrinkage and they move toward the center of the cornea. And this demonstrates that a wedge of host corneal tissue has been drawn toward the corneal center and it's simply easily excised when you tree find down. You've got the host corneal button, you have the crescent or two crescents of cottery and it's simply done and doesn't take a lot of time. A half millimeter larger tree finder was used to cut the donor button and was used to cut the host button from the patient's eye. An oversized graft is not necessarily a problem and that doesn't factor in on the astigmatism factor. One doesn't want to use a smaller donor button than the size of the hole on the recipient eye. That has happened in the history of ophthalmology and it was not good for them at all, it was a big problem. A hand-driven tree finder was used to cut both the donor and host buttons until donor corneas started coming from the eye bank prepared with the scleral cuff. These latter donors were punched out using a tree finder with corneal endothelium side up and I usually used a disposable tree finder for those. Okay, an article by me on this subject is published in the American Journal of Ophthalmology, volume 90, Brace Yourself, August 1980. There's been very little comment response to this article, which I don't know if I'm surprised but I know it's a great procedure and I know I did it and I know I never had cause to regret it. So I kind of wondered, but anyway, it does work and part of why I'm obsessed about it is Dr. White thought it was great, we operated together and he saw me do it and he liked that. This is the article, look at the top two articles, one's by Dick Troutman, a corneal surgeon for whom I have lots of respect in mind and Dick Troutman used to sometimes say, he said, I have a videotape, he says, I don't know if such and such, a doctor happened to read my article and I look at that and I think I wonder if Dr. Troutman noticed mine is right next to his and anyway, no comments. That's okay, I still think a lot of him. So by the way, basically in summary, an ideal time to take measures to reduce excessive amounts of corneal curve disparity, which is aqueous humor lens astigmatism is during keratoplasty. This can be done by a technique that involves the use of thermo wedge resections. This is a repetition, but it's worth listening to. Topical coders used to shrink corneal collagen and draw a thermo wedge of corneal tissue into a previously marked area and this helps you understand the mark was made by gently pressing the tree fine, which is used to cut the recipient button on the patient's cornea and this procedure affords the same net effect as the tissue wedge resection combined with keratoplasty. This technique in the article here resulted in reduction of astigmatic error by as much as 8.5 diopters, there were some big astigmatic errors in that. And here's something to think about. Maybe we worry if somebody has a cylinder in one direction or they're going to worry if it's now if the cylinder axis is in another direction. Well, they never got used to that cylinder axis in the first direction because they never could see with that. So that's not a problem. And the patient's just commented very little about this and they're pleased to be able to finally see using contact or spectacle lens. Some of the things here that we will discuss correct misconceptions that most or all of us learned. Wait, oh, I touched something there. I'm gonna put the media volume up. You're on the computer PC. An associate of Orson's in the Pacific Coast Odo Ophthalmological Society wanted to be certain that Orson was published. And he did so by including Dr. White's true three lens eye concept plus his work on trigonometric ray tracing and third, the pressure dynamics in glaucoma in the 10th and 11th editions of the book general ophthalmology by D. Vaughn and T. Ashbury of Lang Medical Publications. That good old familiar yellow book that so many of us have referred to chapter 24 covers the optics and ray tracing, the pressure dynamics and glaucoma materials in chapter 14 of editions 10 and 11 of this fine book. Orson remembered all of his mathematics and physics. He would find and read the source material of many great scientists of long and go. As an example for Boyle's law, he went to the original writings of Boyle to read about pressure within a closed system. He did this in many disciplines. Let's consider a few of Orson's teaching and projects and let's begin with the three lens eye concept. This is the truth as we will demonstrate. It is not what we have been taught but it definitely is true. Contrary to popularity leaf, the cornea has almost no power of refraction in the optical system of the eye. Since the cornea has been regarded as the most important lens of the eye for over 300 years, some explanation and proof is in order. The cornea is important optically only in shaping the anterior curve of the aqueous lens. If the cornea is removed mathematically but the aqueous lens is kept in its former shape, ray tracing methods will reveal that the image location and quality are for all practical purposes the same. Let's look at a diagram of the three lens eye. The first lens has just been described as the aqueous humor lens. All three of these lenses have a front surface and a back surface and a refractive index. The second lens everyone will agree is one of the lenses of the eye. That is what Dr. White calls the lens lens. It is sometimes called the crystalline lens also. The third lens, which also has a front and back curvature and an index of refraction and a surprise to most everyone is the vitreous lens. Morrison often described this as the thickest and perhaps most important and one of the most difficult lenses to make if one were considering a three lens system for some purpose such as an optical lens for a camera. Let's just restate a few important things we've been discussing. The normal cornea is not a lens. The normal cornea may have a very slight lens power but it is certainly not a plus 40 diopter lens as we have been taught. Another item of importance is there is no such thing as corneal power other than the slight amount that I have already mentioned. One hears the term corneal power quite often at various courses and meetings but there is no such thing. The proper two terms are corneal curvature and aqueous power. The third term, corneal astigmatism is better reworded as a corneal associate that it results in aqueous lens astigmatism. For this reason there is no real corneal astigmatism. Let us consider a series of slides. Orson White was at a dinner once with four brilliant Chinese physicists and they asked him what was new in his field and he said, well I'm working on helping my profession understand some of the true facts of optics and let us do a little demonstration right here at the table. This first slide shows the cornea which we will call analogous to a crystal goblet. One can see through it when it contains air. Banana. In the second slide, one can see through the corneal goblet filled with air and a Christmas cocoa can with alternating colored stripes in it. There is no magnifying. It is still rather clear looking through the goblet. In the third slide, let us add water to this goblet and it now becomes analogous to the aqueous lens. There is no power in the walls of the goblet itself but there certainly is power in the waterlands. And on the fourth slide, one can place one's morning newspaper behind it and read the paper in case you forgot your reading glasses. None of these lenses in the three lens eye are thin. So algebraic, thin lens equations are useless. Very few persons have been trained in this three lens concept in ophthalmology. They have in physics and in optical engineering but it is true. How about radio keratotomy and conductive keratoplasty? These procedures reshape the aqueous lens by changing the curvature of the cornea. The keratorefractive surgery that removes or adds corneal tissue does actually make a lens of the cornea. So in this case, we would then have a four lens eye. Trigonometric ray tracing is the true way to analyze optical systems. The classical reference for ray tracing is applied optics and optical design by Alexander Eugene Conradti, volume one published in 1929. Volume two was delayed by the death of the author but was completed and published in 1960 by Conradti's son-in-law, Rudolph Kingslake. Kingslake studied under his father-in-law Conradti at the Imperial College in London and was then director of optical design at Eastman Kodak Company for 30 years and taught lens design in the Institute of Optics at the University of Rochester for about 45 years. Kingslake understands optics very clearly and he just can't imagine that ophthalmologists think that the cornea is a power lens. I think Orson might have liked to ask him to perhaps help out in demonstrating the truths of optics to ophthalmologists but Kingslake seems so disillusioned by our colleagues that he was not available to help in that sort of a project. The techniques of corneal wedge resection and corneal relaxing incisions. The technique of wedge resection was first developed in 1967, first published in 1970. We use a qualitative type of keratometer, a ring of 12 lights which reflects back from the cornea to the operating microscope and gives us an idea of tight, loose sutures, steep, flat meridian. It is not quantitative and in my experience, no quantitative keratometer is truly quantitative intraoperatively during keratoplasty or wedge resections. When you use monofilament elastic sutures, the folding of the cornea at the resection area tends to accentuate the effect. So we are compressing at the wedge site, pulling the cornea together, making the flat meridian steeper. The operation begins with the evaluation of the stigmatism as determined by the office keratometry with the surgical keratometer. I'd like to see at least 50% overcorrection with the wedge resection, sometimes up to 100% in the higher degrees of the stigmatism. We mark the axis. We mark the axis. We make the initial incision using a diamond knife with two blades that has a variable width, which we adjust now to approximately one millimeter. We do approximately a one millimeter resection to just excise the scar. The most I've ever correct is about 30 doctors and the least, probably six or seven doctors, tend to use the relaxing incisions and now the trapezoidal keratotomy when we have a lesser degree of the stigmatism. And then we try to remove this in depth. And here the wedge becomes a true wedge as you approach decimation. I don't know why that's slid on the side, but it's basically okay, I hope. And you can see we have got a perisentesis and this is desirable. Since we can't close unless we have released some aqueous, one has to be careful, however, in a faking eyes not to create a victorious wick. And let's just look at the wedge resected tissue. You can see that it's reasonably even and about the same thickness throughout. The keratometer image, so that it will be, when we finish tying them, it will be oval in the reverse oblique direction. And now we have the... Now notice the difference. Instead of along this axis, it's more of this. Seven closing sutures in. This is the B and L keratometer image that we don't use because we have corneal topography, but this is what you see and you have to remember that the flat bulge is 180 degrees opposite of where the really flat spot is on the cornea. And here shows that. Viewing this operation on a right eye from the patient's right side and slightly below. The top of the patient's head is at the upper left of the screen. This patient has hereditary anterior membrane dystrophy of grason. Elateral canthotomy is performed for less squeezing. To reduce potential pressure on the eye from eyelid squeezing. Inferior and superior rectus bridal sutures are inserted using four-row black silk. The epithelium is scraped from the donor eye, except in certain cases, such as chemical burns, where one hopes to preserve a maximal amount of epithelium. A hand-driven castro viejo 7-millimeter tree fine is used to penetrate into the anterior chamber. Here is placed through the edge of the donor button, which is then cut free using cats and scissors. I have had no problem with promptly used refrigerated donor eyes. The same tree fine is pressed on the patient's cornea to make a mark in the epithelium. Goldruth cottery is placed just inside the tree fine mark at the flat spot or flat meridian of the patient's cornea. Notice the traction lines as the anterior corneal collagen contracts, drawing in a thermal wedge of tissue from the peripheral cornea to be cut and discarded with pathology butts. Additional pyrocarpene drops were used at surgery to constrict the somewhat large pupil. Indicates maximal corneal flattening at the three o'clock area. In this diagram of a thermal wedge procedure centered at three o'clock, the dots indicate thermal cottery applications. The shaded area represents the crescent wedge of corneal tissue drawn into the diseased button to be excised. A double thermal wedge is performed in cases such as this one where preoperative keratometry shows six to eight diopters or more of corneal cylinder. The hildre's cottery marks are further from the actual tree fine cut than they were from the original tree fine mark. This shows how an extra crescentic wedge of anterior corneal collagen is drawn into the button to be discarded from the patient's cornea. The ultimate effect here is like putting a round graft into a side with an oval anterior opening and a round posterior opening. Gently rinsed with balanced salt solution, placed on the patient's eye, and sutured in place using interrupted 10-ohl nylon sutures. Total of 16 sutures are usually used. I leave the knots exposed and slide them to the recipient side of the wound in order to enhance wound healing. The anterior chamber is refilled by gently irrigating balanced salt solution between the wound lips through a 30-gauge cannula on a 2CC glass syringe. The wound is tested for leaks. The wound is now completely watertight up to 24 hours at a fox eye shield. Eye shield is placed upon the operated eye. Okay, in the final summary, the cornea has no power whether one considers an air corneal interface or a water corneal interface that you'd have in your swimming pool with no goggles or a mask when you're swimming. We all know that when we see our patients, we tell them things, the more alarm they are, the more likely they are to hustle to Google and look it up and see what they think of what we had to say. I took a look at Google on this subject. Here are four statements I found in Google. The cornea provides two-thirds of the total power of the lens power of the eye. This is Google, not Joe Hatch. The cornea provides two-thirds of the total lens power of the eye. The cornea is about a 43-diopter power lens. The cornea is the first lens in the human eye. The cornea is the strongest lens in the human eye. All four of those statements have one thing in common. You're dead wrong. Hope someday some bright resident will take it upon themselves to get involved in trigonometric ray tracing and help the Academy of Ophthalmology understand that we, of all people, should adjust our training. Now, we do a lot of good work in spite of not understanding it, but we shouldn't be in the dark either. I do have some reference. I don't have the results of the cases that I showed in this article, but I do have some here if you'd like to take a look and see what that's like. Just take a reprint if you wish. And this is South Canyon. South Canyon is south across the Provo River and Provo Canyon from Vivian Park. Go up to the Girl Scout camp and saddle up your horse and go back in the hills. And that riderless horse is my horse, Voodoo, a great horse. And the thing I like the best about this picture is that if you look carefully, you'll notice that there are no empty boots placed backward in the stirrups of that riderless horse. Thank you. Are there any questions? I'd be delighted to hear some. Yes. Thank you. Yes, Dr. Tabin? That was that one case. I was always changing things around and I thought if I could get a little, irritate the corny a little bit, maybe a couple of blood vessels to grow in and I was telling Val before the meeting, every time I saw a little blood vessel go from the host end of the graph, it's like putting a nail between two boards. I know I could take that suture out. I only did that very briefly and I happened to do that on that one case that we did film. I do invite you to pick up the reprint. There are eight cases reported here, but I did them whenever I had a big cylinder. I did this using this procedure afterward and the patients were all able to see one way or another. When I was fitting a contact lens, I used the post op. I used the fiddle lens. It was about one-third of the steepness between the flattest and the steepest. I did if you had a 44 and a 50 diopter corneal reading, I put in a 46 back curve out of my trial scent. See what I thought about it? No bubbles, so on. See how the fit looked and I go ahead and order that. All the patients I did with this liked it. Some of them had some serious problems. Didn't see all that well anyway, but they all had improvements. So it's a real thing. I don't know if it'll ever catch on. They sure caught on with me. Thank you. With desicc and a leaf from other grass, all that's took the test is probably less than an issue than it used to be. No, this is still an issue. Yeah. One of those. Take one. And take a reap from you. Good job. Thank you. Oh, God bless him. He deserved it. Yeah, a great bright guy. Yeah, well, he was. Thank you, Chris.