 about seven years, came really with the concept of building the Center for Translational Medicine, which sole purpose really, in my mind, was to quickly push towards therapeutic development for my disability generation. So, you know, Randy Olson and I talked a lot before it came to me, because I think what we're trying to do here is pretty unique. And maybe next time I'll put a few slides together and really show you what we're doing. But we're now a group of about 45 people. Had a monstrous partnership with Allergan for the last three years, like I was just telling you. And that kind of fell apart when they were purchased last August. So, they've been out looking for a new partner. So, we're talking about Biogen and we're talking pretty seriously with Regeneron. And these are big. This was Regeneron deals about an $80 million arrangement. So, it's a lot of fun. But today, you know, my task is to really walk you guys through kind of structure, function, pathology, the corroy, RPE, vitreous retina, you know, things. So, if you're bored, you know, a lot of this is just kind of didactic. We can talk about anything you guys would like to talk about. So, I can take it in any direction. And there'll be two parts. I think they give the second lecture in early May. But what I'd like to do today is I'd like to talk a little bit about kind of ocular retinal development because it's always helped me understand the structure of the eye much better if I look at it from a developmental perspective. We'll talk about topographical features of the retina itself and actually the back of the eye. You know, there's a lot of topology that I think you don't think of from reaching to the next. There's no good way to talk about the retina, so I like to kind of talk about the outer retina, the abascular piece and I like to talk about the inner retina, the vascularized piece. And we'll probably in, maybe we'll get through the inner retina today and then next week we'll talk about growths membrane and corvoid and the victories. And I'll kind of use macular degeneration just because I'm familiar with it. And we can talk about some of the age-related changes that occur. So, before we start, and I mean you may have seen this, but don't say anything if you have. But tell me about this retina. Do you see normal, abnormal retina? Hmm? It looks abnormal. Jenny, why? But I haven't seen retina before in that long. Sorry, I will. At least this corner doesn't work. All right, so layers. Tell me about layers. What's this for? It's retinal pigment epithelium, right? Corvoid. Does corvoid look good, bad, indifferent? I don't know. I guess those vessels look a little enlarged. These? Yeah. They're actually pretty normal. That's coriocapularis and these are the mid-sized arterioles and veins. RPE looks great to me. What about the retina? Don't look normal? Yeah. Okay. Eileen? No guesses? I feel like I remember. What are the layers? Normal. That you're in the phobia? Okay. Thanks. Is it just like... So there's not much? No, so Eileen's absolutely right. It's the dead center phobia, so it's perfectly normal. So that just gives me a little understanding of where we should head today. So if I think about ocular development, the retina really form actually a whole lot, but the retina is kind of the crux of the ocular development. It really forms as these outpocketing of the diencephalon, right? And, you know, it's a really simple way to kind of think about eye structure from my perspective. These are some pictures I took years ago. But here's this epithelium of the diencephalon outpocketing, and then it's almost like, you know, you push your finger in here and two layers of that epithelium fold back on itself, okay? And if you keep kind of that structure in mind, it always helps me apical basal, right? So this is the basal surface of the epithelium. This is the apical surface of the epithelium. And when the retina and RPE, this fold will become actually the RPE mineral retina, okay? And same picture. This is a hamster, but same idea. The original fold of the diencephalon comes out and folds back on itself. This layer becomes the retina pigment epithelium. This layer differentiates into the retina. I mean, fascinates me that one layer remains as a cuboid of epithelium throughout life and the other layer differentiates to such a large extent. So you can basically build an eye from that simple outpocketing. The limbs is actually an in-pocketing of the surface ectoderm. And so that's why it's round and why you have a capsular bag, right? The basal surface is on the outside, which gives you a nice structure for transfer, for putting in a new lens. So if you think about that, you know, this becomes the vitreous. The tip of this outpocketing or this folding on itself becomes the iris. And it's a very simple way to kind of keep track of things. The neural retina itself, I think you're all familiar, goes through over time, goes through a differentiation. The earliest cells that are born in the retina are the ganglion cells down in here and probably the last cells that form are really the ruff fold receptor cells. So a very logical process of development. You can see some human eyes that we took photos of up in our lab, which you can see at this very early stage, about 10 weeks. You can see all the mitotic activity going on in this retina. You can kind of see over time the birth of this ganglion cell layer. And you can see a little bit going on here with kind of differentiation over the two outer nuclear layers. So again, you know, today we'll talk about kind of the neural retina comprised of, of course, neurons, blood vessels and glial cells. I'll talk specifically about the RPE. And it's really this retina that, of course, subserves this linear flow of information from light striking the photoreceptors to their ultimate transfer to the brain through the ganglion cell layer. Again, you know, retinal histology can be really, really complicated, but you can break it down and really think about there are really three tiers of cells, right? And those make up the nine or 10 layers that we talked about. And I remember, you know, when I first started, it was very confusing to look at this and try to put it all together. But just kind of focus on these three layers of cell bodies, right? So the outer most layer for the receptor nuclei makes up the outer nuclear layer, if you will. Inner layer is the ganglion cell layer. And then in the middle are typically, there are a lot of cells, but they're bipolar cells. And then all the crosstalk cells, the anachronism, the horizons. But I like to kind of think about this, and you can always get back to your layers if you really kind of think about three tiers of cells. So topographical differences, the one that you're probably most interested in is commissions would be the topography changes that occur in the macular, right? Very important region of the eye. Very unique primates. Sub serves really your ability to see fine detail and saturate color vision, which we don't talk about. Again, topographical differences, and it's, I think, I mean, caught this one dead on, right? The dead center of the macular, the phobia, doesn't have an inner nuclear layer of ganglion cell layer. So I like to talk kind of about anatomical phobias and anatomical maculas. Some people like to talk about functional phobias and functional maculas. But quite simply, the macula's about 5.5 millimeters to 6 millimeters in diameter centered on the phobia. And you can really define the anatomical macula by the density of the ganglion cell layer. So everywhere the ganglion cell layer is more than one cell thick. That defines the macula. And as you get out further periphery, the ganglion cell layer goes into one or two layers, okay? Dead center anatomic phobia, about 1.5 millimeters in diameters. Really the region that contains only photoreceptors and, of course, glial cells, but this region from about here to here, anatomic phobia. Phobia is really a subsection where there are absolutely no rod photoreceptors. You can see red here is rod, green has come, and you can see a few rods here. So this dead center region, about a third of a millimeter in diameter, is your phobia. And, of course, one very striking characteristic of the macula is the sequestration of these pigments that Paul Bernstein has spent a lifetime on. Highly sequestered as luteum and xiozantin in the macular region. And, you know, grossly if you look in, especially in young people, you'll see that bright yellow accumulation of pigment called the macula luteum. Actually located, most of that material is located in the fibers, the axons of the cone photoreceptors in the macula. So if you're a cone photoreceptor in the dead center phobia, you have these really long axons that push out loudly, right, because your whole macula is designed for really being highly sensitive, and you don't want those axons in your way. But for some reason that we don't quite understand there's sequestration of these pigments, the xanthophils, the carotenoids, mostly molecules that you can't make yourself. So they come primarily from diet. We think their primary role is an antioxidant, and probably they absorb short-weight blue light for some reason. Paul, I'm sure, will talk extensively to you about that. So again, no great way to divide up the retina, but let's kind of break it down into the outer retinal complex comprised of RVD photoreceptor cells. This whole area is a vascular, right? So from the synapses sitting right here, this whole layer, the photoreceptor layer, a vascular, so it receives all of its nutrients from, primarily from the coroid bone. Interretinal complex, if you will. I like to define it by the region that's the other two layers. It's vascularized, and it's very complex. So here's your phobia again. This is actually from a monkey, and you can see very nicely all the features we've just talked about. I'm surprised if you'll come up against some of this in the future. What are those, like, on the inner surface, the cystic spaces? Probably just, sorry about that, probably just the end feet or cell end feet that cystic changes in those end feet and probably a little bit to just things like that. But beautiful structure. I mean, you can really see this maculose, the exquisite Coriocapallaris. Here's your intermediate vascular layers. Phobia receptors, of course, you can actually see these axons in the endless layer. And you won't see an endless layer anywhere but the maculose. So it also helps you. If you have this really thick layer, you know that you're in the maculose. And the same in an OCT, you can actually really know where you are in an OCT. If you're in dead center, oh, yeah, it's apparent, but you can use that diagnostically to really know where you are. So, outer redna, photoreceptors, two classes of course, wads and cones. And they're highly polarized cells with their synapses in the outer synaptic layer. We'll come back and talk about more details. And the tips very much integrate with the retinal pigment at the feeling. Incredible structure, incredible requirement for oxygen. Highest oxygen use in the entire body. And there's actually a huge surplus of oxygen in the coloid. We're not quite sure why it's that high because even the photoreceptors can't use all the oxygen that's there. But a terrible environment, okay? And we'll come back when we talk about DRPE. This whole complex because of the high amounts of oxygen, the tremendous amount of liquid turnover, the fact that DRPE cells don't replace themselves so you get what you get when you're born. But this whole interface is a hugely caustic environment. And it's at the crux of a lot of the disease that you see. And we'll talk more about that as we move through. Rod photoreceptor system, basically one type of rod, maybe two types of rods. You have about 120 million rods in your retina. Of course the entire rod system is a chromatic, really meant to work in dim light. Photoreceptors are really sensitive. They can respond to a single photon of light, but then they distribute that signal out to, so lots and lots of rods are connected to a single bipolar. So highly sensitive, but the signal's damped out and that's why the vision from rods is not very acute. Told you a lot at night, but not acute. Column's 6 million, most are concentrated in the macular region. Photopic system, really very low sensitivity, but very dense packing, especially in the fovella. Very responsive, one cone per one bipolar. So this is where you really get that fine acuity in the macular. Photoreceptor streak glasses, I like to talk about L, L and S cones and it just really refers to their function and the wavelength of lights that they interpret. And again, pathologically, almost all the cone nuclei sit on the outermost level of the outer nuclear barrier and it's always a good thing to remember, especially if you're diagnosing a disease based on histology. So retinitis, pigment, and toaster very often all you end up with in that disease is a single row of cone and very diagnostic. Of course, lots of topography differences in the cones, especially again in the macular region, I think most apparent is this really densely packed set of tone photoreceptors in the macular. I have a very strong feeling that these macular cones are actually very different than the cones throughout the body. You can see as you move out from the macular in any direction, the cone inner segments become much larger in diameter as compared to these fovella photoreceptors. So very dense packing in the dead center, fovella, highly sensitive, so it subserves your ability to see fine acuity detail. So photoreceptor cells again highly polarized cells, basically an outer segment. This is where all the action occurs, of course in the phototransduction cascade. So outer segment really connected to the rest of the cell, the cilium. These cilia are turning out to be really important regulators of communication between the cell body and the outer segment, probably far more than we knew. Inner segment region just packed, especially the cones packed with mitochondria, lots and lots of energetic need in this region. And then of course at the proximal end of the photoreceptor and the synapses, which transfer everything that happens out here down to the bipolar cells to the inner brain cells. So very different structure between rods and cones. We typically, these disc membranes in rod photoreceptors are independent. They're actually ensheved by an outer membrane, so you can kind of think about these as stacks of coins. Very different than the cone photoreceptors, which the disc membranes are contiguous with the outer membrane. We actually know, we don't know very much about cone function if you think about it in humans. And it always baffles me. But very striking, you can see just how beautiful these discs are. But some numbers, you know, these discs are added to the base of the outer segment on a daily basis. There's about 600 to 1,000 discs per stack or make per day in a rod photoreceptor. And then these discs actually migrate distally to the tip of the outer segment where they're eventually spagged as a toast and shit. And, you know, I don't know if you guys have met Dean Bach. He's a good friend. He's been out here quite a bit. But he actually did these experiments initially to show that with Tradiated Loosing that you saw a lot incorporated into these new discs and over time that band of Tradiated Loosing moved until the day it was shipped. And Dean tells a great story about the last frog because he predicted that it would take about 10 days before this event would happen. This frog was dying from radioisotope exposure. He hated it so much. He'd taken it home and told, you know, that 10th day where he actually showed that this really happens. So the point is it's really the damage to all the lipids that the lipids need to be turned over. We think there's actually reuse of some of the proteins like rhodopsin and that's an interesting concept. But the rod then stays the same length throughout life pretty much. So just some facts that I think are kind of cool. So you have 125 million rods in each of your retinas. A single RPE cell attends to about 200 photoreceptors. Changes a little bit with topography. But you're really shedding about 375 meters of outer segments per day. And if I calculated this right, it's about 10 million meters of disc by the time you reach 75. So the point is just massive energetic requirements by this retina. And I think these are just fascinating numbers. When we talk about the RPE, the RPE has to manage all of this. So it's amazing. It's not surprising that there are a lot of diseases that are caused by dysfunction. And another number of 9 million oxen molecules are synthesized every second. So it's pretty incredible system. Again, you can see the cones incorporate that band of tritiated loosing. And it moves distally. The cones, we don't know a lot about how the oxen is turned over in the coming out of segments. But we talk about kind of molecular replacement of oxen in these cone photoreceptors. There's a single paper that was published years and years ago that says in humans that cones do shit. Cone outer segments are much shorter and the RPE really have to reach down a long ways to find the tips of those cones. And this whole process of outer segment phagocytosis by the RPE has really been worked out over the last three or four years. So we know a lot about the receptors that actually recognize and pinch off this set of disks. It's a very standardized process about the same number of disks that are shed every day. And you can see that in some of these photos that we've taken in the lab. So it's a very interesting process where these packets are actually pinched off. We think there's a lot of recirculation especially of rhodopsin and ribopsin and then probably redistributed back to that. And of course you get lectures on phototransduction. I'm sure it's at Wolfgang probably. I don't know if you've had those yet. But the real function of photoreceptors is phototransduction, right? To take those electric or those light signals and turn them into electrical impulses that are transferred to the brain and vision is in turn. So my favorite cell, the retinal pigment epithelium again, really quite a cell. Highly cuboid in nature. Extremely polarized cell. If you think about what this cell has to do it has to get rid of waste products from the photoreceptors. It has to transfer all kinds of oxygen and other molecules from the carotid vasculature. It's non-dividing, like I said. The pseudopoia on one end serve a very important function of course probably in retinal adhesion but also in the spagatosis. These basal infobings become really important. They increase the surface area a million fold compared to the epithelium's flat. In a lot of age-related diseases those basal microvilli are lost for reasons we don't completely understand. Function of course, the primary function is to visual cycle to turn over trans retinal and to keep it circulating back to the photoreceptor segments again. I think we'll talk to you about that in detail. Tremendous functions again. Trans epithelial transfer of metabolites and waste products going in both directions. This cell has to decide whether to traffic proteins to one side the other side, both sides. Fascinating. It serves really as the outer retinal blood retinal barrier. And that's subserved by these type junctions that occur between cells. So it really doesn't allow extracellular transport of materials between cells until of course they become pathological. And visual cycle is really a fascinating system but basically what you're doing is 11-cis retinal is being turned into all trans retinal once light hits the rhodopsin, of course. And then that's converted to 11-cis retinal and re-isomerized by the retinal pigment epithelium and then served back as all trans retinal or actually 11-cis retinal to the photoreceptor cells and that's the visual cycle. It's really a pretty straightforward system. The proteins that mediate that of course Wolfgang has been deeply involved in identifying a lot of these proteins that modulate the visual cycle and he's done some fantastic work. My sole contribution was we actually sequenced the L-rat gene which was this isomal hydrolase that had been hypothesized to exist for a long time and we discovered about 10 years ago that there really was a protein and identified it as L-rat. Again, the junctions between RPE cells probably most important are these type junctions that really form a band between adjacent cells and they really do create that outer blood retinal barrier. Inner blood retinal barrier of course is the epithelial cells of the retinal vasculature and you can see that in this slide just is foresting actually so it was a foresting injection but you can see how well that RPE blocks the ingress of the foresting from the corvoid into the retina and then these of course would be the blood retinal barrier and the retina subserv by the vasculature. Lots and lots of age-related disease related changes in the RPE. Certainly, we talk a lot about the emulation of lipophugium probably true in normal aging but I think probably less true in once you develop macular degeneration. Clearly cell density of the RPE changes in aging and changes in all kinds of diseases. Normal aging we calculated once that you lose about 10 to 20% of your RPE, macular degeneration somewhere about 30 or 40%. To the point that the RPE really can't maintain its integrity and that's a lot of what you see in geographic atrophy. When it finally gives up the dose it gives up the dose. Lots of thinning, these are actually both taken from macula in about a 15-year-old and an 80-year-old. So tremendous changes in the RPE. And again, accumulation of lipophugium does increase with age. And of course you guys use lipophugium to detect disease and that is really the basis for this autoforestation. Other disease related changes that you might be less familiar with this is the basal surfaces of an RPE, this is gross memory but there are a lot of changes in the basal lamb of the RPE especially in macular degeneration. This material that accumulates very often between the basement membrane of the RPE and its own plasma or basal plasma membrane is called basal lamina deposit. We've shown over the years that it's integrated, it starts as these little clusters integrated into the basal lamina and then this material can just become huge and actually actually look to maybe 30 or 40 microns that really serves to push the RPE off the basal lamina and away from the coriopapillaires. Very often you'll see this is a cult neobascular frond that actually grows in this material very often, very ornate material. We don't know, we think it's type 6 collagen. We've shown more recently that it's very much directed by chromosome 10 driven macular degeneration associated almost solely with chromosome 10 disease. So, interphobreceptor matrix. Anybody know very much about the interphobreceptor matrix? So, there's not a lot of people that even think about it anymore so I've spent a long part of my career years ago but basically all the space between the outer segments and the inner segments of the photoreceptor cells is built with the material of the interphobreceptor matrix. Probably serves a lot of functions that we don't know of but I think probably most importantly it probably serves to keep photoreceptor outer segments aligned with the so-called stoves effect. We've never quite understood why they stayed perfectly aligned and it's probably this interphobreceptor matrix that helps to mediate that. Certainly, we know that the matrix components are made by both the RKE and photoreceptor cells and there's probably a lot of function here in retinal adhesion and maintenance of photoreceptor viability. Well, I think were there some mutations in that associated with the dermatology? You know, I spent my life. So we described these two major proteoblackins, IMPG 1 and 2. It took us, I think, this gene took us almost five years to identify and clone and today, of course, we could do it up in the lab in a single day which is really frustrating but we were actually able to develop a technique to isolate this material from humans. This is an isolated sheet of IMPG and these are where all the common photoreceptors were sitting and it depends what you're saying but you can see the very unique structure of this matrix material. So these two major proteoblackins as far as we know they're synthesized only in a lot of experiments years down by in monkeys where we were able to show that this matrix really mediates retinal adhesion. So here's a normal monkey interphotoreceptor matrix and we did a lot of this with Mike Murray. We could stretch this material to a huge degree and we did a lot of experiments and I think proved very convincingly that this material is important for adhesion and I've always thought if you could get back into a retina it was degenerating and maybe get it to synthesize this material again that we might have some hope in preserving photoreceptors. But I mean to your point there have been a number of diseases maculopathies that are associated with mutations in these two interphotoreceptor matrix proteoblackins. So that's been fun, we always hope we would find one of those diseases and we actually thought the other district would be it but it turned out it was the gene just next door. So in a retina complex again we've talked about this photoreceptor layer and it's the outer, the outer nuclear layer the other two nuclear layers the inner nuclear layer and the ganglion cell layer I'll talk about kind of as the retina complex and it's this complex it's also vascularized right so there's again I think it's simpler if you think about these nuclear layers so this layer is primarily ganglion cells this layer you can think of as being you know 80% bipolar cells so the cells that directly connect photoreceptors to ganglion cells but you end up with all these other cells that actually transfer information laterally between adjacent photoreceptors between themselves we'll talk a little bit about that and of course the inner aspect of that layer is the inner limiting membrane which is really nothing more than the basal lamina of the Mueller cells so again another basal lamina and remember from that out pocketing this was one layer of the basal surface of the epithelium right so this is basal this is apical to photoreceptors one that epithelium folded back on itself right so you really have apical to apical in most of your two original layers of the epithelium and it's helpful I think because that teaches you where these basement membranes are set so bipolar cells and I'm not going to bore you with a lot of this there's a lot of detail about apical giving lectures anymore not at all it's too bad and you guys should really try to get her to come you know she was such a pioneer in a lot the identification of a lot of these bipolar cells of course primarily convey gradients between the photoreceptor cells and the ganglion cell layer they have pre-synaptic connections with the rod photoreceptor cells with comb photoreceptor cells and with horizontal cells post-synaptic connections of course to ganglion cells and amicron cells which sit primarily so there's kind of a level in there horizontal cells really sit their nuclei sit in the outermost region of the inner nuclear layer and they really sub-serve primarily sub-serve talking to a adjacent photoreceptor cells talking to laterally interconnecting with these photoreceptor synapses they will take input from a lot of photoreceptors okay and that's why in the rod system it's it's not very very good at finding cuny because you have a lot of these being connected by by a single horizontal cell you see this is an antibody we made years ago and you can then see that their axons really are sitting in the outermost portion of the inner amicron cells do the opposite they sit on the other border and they really sub-serve connections between ganglion cells primarily but also with bipolar cells to some degree and these interplexiform cells they actually we don't talk about them a lot but they connect the two interplexiform layers and again mediating crosstalk from all that but primarily take input from amicron cells and we don't know a lot about their function ganglion cells is probably the most complicated and he guesses how many types of ganglion cells there are I mean it'll debattles you when you start thinking about all this structure but like I told you earlier when you see piled up ganglion cell layer you always know you're in the macular and there are just numerous morphologies and all kinds of functions they're on cells they're off cells the retina really is an amazing structure I really need science is going on now because we have the ability to isolate single cells in the retina and to do things like RNA sequencing and that is just really along with morphology has started teaching us about how many different cell types there are so I just saw Joshua sayings the other day and he thinks there's about 30 different ganglion cells sometimes and that's all based on a combination of molecular and physiological and morphological data so he's developing this classification did you guys all see the talks David Cochran's talks fantastic stuff this whole melon opson story so you know subsets of these ganglion cells contain melano opson really a fascinating story three types of glial cells in the retina if you really want to call microglial microglial that we will say Miller cells of course they stretch from the inner limiting membrane to the outer limiting membrane they take up probably the largest volume of the inner retina astrocytes which are these really cool cells that really mediate crosstalk between retinal vasculature and retinal neurons and then microglial which are immune cells the macrophage length cells so astrocytes shown in red you can really see that they're talking to each other but they really talk to the vasculature we think they're not neuroepithelial origin we think they migrate in and early in development this beautiful picture you can see that this whole network of astrocytes and they wrap around capillaries that modulate capillary tone they really play an important role it's a cell type we don't talk a lot about microglial cells are sentinels if you will almost dendritic cells like in nature and these cells play all kinds of immunological roles and actually are very much associated with this case and the mular cells have always fascinated me they really do this was one of my students drew this these are the mular cell infeed but again the basal lamina the inner limiting membrane is really the basal lamina of these mular cells and they stretch throughout the retina where they actually project all these microglial into retinal space and so probably doing a lot of sensing of what's going on and transferring that information very importantly again there's a pretty tight border here and that's violated in a lot of diseases and we'll come back and talk about that some more in the next lecture but these cells are actually really delicate they're incredibly sensitive but they function to really maintain homeostasis in the retina and so when you see cystic changes in the retina very often it's needed by dysfunction of these mular cells we're learning more recently that they actually transport neurotransmitters throughout the retina we're not quite sure what all that's about and of course you guys will think about these cells a lot in the future because of the pathology that they do exhibit leosis, foaming, retinal detachment very much participate in the formation of epigretinal membranes fibroblastinal membranes and adentrius in a retina circulation of course I think the take home message is there are two layers of capillaries right there's a layer of capillaries in the inner nuclear layer and one in the inside there and a lot of pathology that you'll see particularly in diabetic retinopathy is caused by dysfunction in lots of these capillaries and we're going to talk more about those lots and lots of aging changes in this retina complex lots of ganglion cell death of course especially in diseases like glaucoma can be a lot of intraretinal leosis, extra retinal leosis I think you're familiar with all these things but basically a lot of that is Mueller cells going to rot and the Mueller cell structure I didn't say in the fovea it's one Mueller cell per cone which is really interesting so you start losing Mueller cells in the fovea you start losing the fovea a lot of pathology retinoschesis is one of the diseases you'll probably see most obviously in your clinic practice that involves the inner retina not common but I sit on a couple of scientific advisory reports so this is a huge target for gene therapy approaches right now and I think there's about three trials that are about to start in retinoschesis using gene therapy lots of vascular disease we're going to talk more about vascular disease next time of course your optic neuropathies and just general aging changes in the inner retina and of course a lot of retinoblastular pathological changes and again we're going to talk about and break those down a little bit but kind of in my way of thinking there are diseases that relate to breakdown of that blood retinal barrier right, common diabetic retinopathy macular edema being two of the large diseases lots of diseases that involve various types of aneurysms of those and then of course all the occlusive in these diseases so it goes in more detail so I think we're probably going to think about ending but talk about retinal pathology tell me about these retinas like things okay tell me what you're seeing the nerves are pale I don't see any blood vessels that's the nerve this is just because I'm not a very nice guy this is one of the moons of Pluto just for fun there it is the moon Europa of Jupiter I saw that in Time Magazine and I had to do it so I think we'll stop there it's probably a good stopping point and then in early May I think it's May 8th we'll come back and I really want to talk a lot about the brooks, the ventraries and the corvoid and use macular degeneration to show you good examples of changes in pathology so any questions so I welcome all of you to if you haven't dropped by the CTM at any time just feel free to just spend some time there where we have, I don't, Jean DeWon and Jean DeWon really famous retina guy who's been a translocation surgery he's been coming out a lot so the chromosome 1 and 10 data really coming out nicely and I think Andy Shackett and Jean and not Lowenstein from Israel very famous with a person probably going to be coming out a lot so it'd be great if we could get you all together you probably but drop by any time I'd love to show you what we're doing thank you for coming out again