The Eye Blog

Fixing Retinal Detachments - Perspective

2008-09-26T20:01:00.000-07:00

To place things in perspective, and revisit how we use to fix retinal detachments, let’s begin with an excerpt from the Australian and New Zealand Journal of Ophthalmology. In the article (Banks, CN et al. 1986), a patient recollects his experiences as one of the earliest successful cases of retinal detachment surgery. His story begins when he was 33 years old:

In 1934, when I lived in Genoa, Italy, I had a terrifying experience. One day something like a curtain seemed to split in my right eye; a wall of water descended and shut out my vision. I realized that something extremely serious had happened and went to see a doctor. However, it was obvious that the man did not understand what happened and was unable to help. Thereupon I went to see an eye specialist who told me I had suffered a total detachment of the retina. When I asked him what could be done about it, he said that it could be treated by injecting salt water into the eye and in fact made one such injection.

This fellow’s presenting symptoms, the “curtain” and “wall of water” that “split” and “shut out (his) vision,” are typical of retinal detachments which are commonly associated with partial or complete visual field loss, often acute but sometimes progressive in onset. Back then, the pathologic cause of retinal detachments - retinal tears that developed from the natural separation and pulling of the vitreous humor on the retina – had only recently been elucidated and still remained neither widely known nor accepted. Injecting salt water would have done very little to repair the retinal breaks, but it was a widely accepted treatment for retinal detachments at the time. The patient’s travels and travails continue:

Meanwhile, I received a letter from my parents in Vienna telling me to come to Vienna immediately. There I went to Professor Meller’s Eye Clinic at the Allgemeine Krankenhaus and was seen and admitted to the hospital by Professor Meller’s Assistant, Dr. Urbanek . . . The treatment started with my having to lay in bed for a few days with my head between two sandbags in order to give the detached retina a chance to settle again in its place. Then came the operation, about which I do not know much, expect that it was done under local anaesthetic, that the liquid was drained from the eye and that a needle or needles connected to an electric battery were used. . . During the operating I remember seeing my eye lying on a kind of spoon which was a frightening experience. . . After that came a period of six weeks during which I had to lay in bed motionless with my head between two sandbags which was a terrible ordeal. Then I was allowed to get up and move about wearing what they called a Lochbrille, that is, a pair of dark glasses with only a small hole in the centre of the lenses, the idea being to avoid movement of the eye as much has possible.

The simple sequence the patient describes here, the drainage of accumulated fluid beneath the detached retina and the cauterization or closure of the retinal breaks, constitutes the principal elements of retinal detachment surgery. In the modern era, the cauterization of retinal breaks is performed with lasers or cryotherapy, but in the past it was done by direct needle cautery. The “eye lying on a spoon” likely refers to the use of a speculum or retractors to spread open the lids and retract the extraocular tissues in order to gain access to the eye wall for the actual procedure. The eye itself is never physically removed from the orbit during retinal surgery. Curiously though, judging by the number of times I am asked the question by patients, this perception of the eye having to be removed for surgery remains common even today. Preoperative and postoperative restrictions were more prohibitive back then, and the patient accurately describes the typical sandbag positioning and bed rest which were standard well into the middle of the 20th century for most surgeries involving the eye. The article and patient’s history continue with an account of recurrent retinal detachments requiring multiple surgical interventions over the next decade. In the end, he still ends up near completely blind and dependent on his wife for most of his activities of daily living.

Thankfully, retinal detachment surgery has evolved greatly in the modern age, and we'll explore some of those techniques in future blogs.

Flashes & Floaters

2008-04-28T17:09:00.000-07:00

Well it's been a while since my last post, but we'll return to the issue of retinal detachments here. Detachments generally occur from breaks in the retina, the neurosensory tissue that lines the back of our eye and is responsible for cpaturing the visual image. A retinal break occurs from a tractional, or pulling, force exerted upon the retina by the vitreous humor, the gelatinous substance that fills the back of our eye and lines our retina.

Certain individuals are at particular risk of developing retinal breaks - namely those who are nearsighted, have a family history of retinal detachments, a past history of head or eye trauma or eye surgery, and those with systemic medical disorders affecting the structural tissues that form the eye and vitreous humor. Retinal detachments are more common in men, and race, too, is a proven determinant. Asians and Indians have a higher frequency of retinal detachments, vice versa for those of African descent.

But detachments can occur in everyday normal sighted individuals as well, simply from having too many birthdays. As we age so does our vitreous humor. When we were not yet born, the vitreous was a dynamic biological structure filled with vessels that nourished and helped develop the eye. Yet, by the time we entered this world, the blood vessels had regressed and all that was left of the vitreous was a clear matrix consisting of strands of collagen (a structural protein) held together by sugar molecules. In a young eye, the vitreous fills the back and firmly adheres to the retina. As time passes, though, the sugar linkages begin to break down and liquefied pools of fluid begin to form within the vitreous, a phenomenon called vitreous syneresis. This is what gives us floaters, or the little particles of debris that float around in our eye. This process of liquefaction eventually reaches a critical state, just when that occurs varies but the incidence typically increases in the fifth and sixth decades of life, and the vitreous humor separates entirely from its posterior and peripheral connections to the retina. Called a vitreous separation or vitreous detachment, such an event is often accompanied by flashes and a sudden increase in floaters. In most cases, the process is benign and the flashes and floaters dissipate over time as the vitreous humor continues to liquefy, but in some a retinal tear may occur in areas of abnormal vitreoretinal traction. When a retinal break is present, liquefied vitreous can pass through the defect into the subretinal space resulting in elevation and detachment of the retina.

Well, just how common are retinal tears and detachments? Tears are found in up to 1/10th of the population but detachments occur less frequently, at an incidence of approximately one in every 10,000 individuals. From this we can gather that the majority of retinal breaks, fortunately, do not lead to retinal detachments. Still, because retinal detachments are significantly harder to treat than tears, it befits patients to have any potential tears properly assessed and treated before they might become more serious concerns. If a tear is found, it can be treated right away before it becomes a detachment. That is why anytime someone experiences flashes or floaters or loss of their visual field, even if it might just be a benign change of the vitreous humor, it's important you call you eye doctor and have a thorough dilated eye exam.

Electric Light Baths, Sandbags, & Retinal Detachments

2008-02-17T07:42:00.001-08:00

A century ago, if you were so unfortunate as to have developed a retinal detachment, the likelihood of having your retina reattached, much less retaining any vision at all, was slim to none. A 1912 survey by Derrick Vail, Sr., a founding member and president of the American Academy of Ophthalmology and Otolaryngology, queried American ophthalmologists regarding their knowledge of successful retinal detachment outcomes. Near three hundred ophthalmologists responded and only 20 successful cases in their total cumulative experiences could be documented. With these figures, the incidence of successful retinal detachment outcomes was estimated at about one in every thousand, small hope indeed. Of course, one can appreciate why this might have been the case when they consider common therapy for retinal detachments in the era included medically induced sweats, electric light baths, sandbags, or simply months of bed rest. Fast-forwarding to the modern age, detachment surgery success rates are now well over 90%, and a number of techniques are presently available to achieve favorable outcomes and the recovery of meaningful vision. Now, most of us don’t give much thought to our likelihood of success after retinal detachment surgery, if any time is dedicated to the consideration of retinal detachments at all, so it’s difficult to appreciate these numbers, but modern retinal detachment surgery is truly one of the great achievements of 20th century medicine and surgery. We'll consider retinal detachments and how they come about in more details in my upcoming posts.

Voodoo & the Evil Eye

2008-01-21T17:34:00.000-08:00

This past Saturday I was invited to speak to the local meeting of the Barbados Society of Central Florida. I'd spoken to them before on diabetes and I thought retinal detachments might be an interesting and important subject, but I threw in a little bit about voodoo magic as well.

Most of don't give much serious thought to voodoo, but there are mechanisms by which it can really cause disease. Years ago, I had a suggestible young fellow from Jamaica as a patient who believed his wife was hexing him. Supposedly, she had placed a hex on him which would make him blind, and shrotly thereafter he began to notice symptoms in his right eye. Well, lo and behold, when I examined him he really did have a retinal detachment, a type called central serous retinopathy which can be seen in individuals under stressful situations. But was it voodoo?

Certainly, common sense would have us believe otherwise and no physician would admit to a direct relationship between disease and curses, in this case voodoo, but an indirect connection has been recognized for years. We've all heard stories of voodoo death. Just stories right? Well, that’s what you’d like to believe.

Back in World War I, physicians were witness to peculiar cases of soldiers dying on the battlefields of the Western Front. These traumatized soldiers hadn’t suffered any mortal wounds but they inexplicably died of shock, a medical disorder normally brought on by a critical drop in blood pressure from excessive bleeding. Some of these same physicians later became familiar with cases of supposed voodoo death, and they recognized a connection with the soldiers. They suggested that, just like individuals morbidly terrified by a magic spell, the soldiers suffered from an over stimulation of the nervous system which led to a form of fatal shock. Fear, in other words, stimulated the nervous system to such a degree that the excessive release of tremendously potent biological hormones caused vital hemostatic alterations and, in those susceptible, death.

Voodoo, essentially, is the sinister opposite of the placebo response, whereby a patient’s belief that a medicine will work, even if no actual medication is administered, results in improvement of a medical condition – a phenomenon well documented in medicine. In voodoo and related phenomena, individuals believe that something bad will happen to them and, even if there is no physical stimulus, it does. So, in this fellows case, and that of central serous retinopathy, acute stress likely induces a similar, but more locally acting, hormonal imbalance that alters the hemodynamics of the retina and result in a retinal detachment with vision loss. My patient's detachment eventually resovled as he came to grip with his stresses - as you can imagine he was in a very difficult marriage - and in the end, there really was some truth to voodoo magic in this old wife’s tale – evil eye and all.

Diabetes & Brain Surgery

2008-01-09T20:37:00.001-08:00

I posted this article here because it is a striking reminder of how far we have come in the treatment of diabetes. Just a few decades ago, articles were being published that seriously suggested brain surgery as a treatment for diabetic retinal disease. In this 1968 issue alone of the Journal of the American Medical Association, three separate papers reported on the beneficial role of surgical removal or radioactive ablation of the pituitary gland (the part of our brain that controls hormone production) for severe cases of diabetic retinopathy. At the time, medical thinking held that certain hormones released by the pituitary gland may make the disease worse, and, in what now seems a less than brilliant leap of deduction, some reasoned the pituitary gland must go. So not more than three decades ago, you might not only have lost your vision from diabetes but your mind as well.

Fortunately, a generation of astute physicians recognized that patients who had diabetes and at the same time certain other retinal diseases that naturally damaged the peripheral retina, such as syphilitic retinitis, rarely developed the complications of diabetic retinopathy. This was because the concomitant retinal diseases had already wiped out the areas subject to severe ischemia in diabetic retinopathy. Like Einstein, physicians made their own quantum leap – without the ischemic stimulus, diabetic retinopathy did not seem to progress into its advanced stages. If only they could treat or cauterize the ischemic retina that develops in diabetes then they might be able to slow down the progression of disease. Meanwhile, they could also cauterize any leaking blood vessels present in order to decrease retinal swelling. All of this might prevent the severe loss of vision that was, up until then, part and parcel of diabetes. Well reasoned indeed but what was missing was a safe and effective tool by which these outcomes might be achieved – and we all now know that turned out to be the laser.

Einstein and Lasers

2008-01-02T16:40:00.000-08:00

Albert Einstein conceived the principles of the laser nearly a century ago. Though many would argue his greatest contribution to science remains the theory of relativity, Einstein did not receive the Nobel Prize for that body of work. He did receive it, though, for his work on the photoelectric effect. For decades, scientists had observed and wondered why electrons were emitted when light shines on a metal surface. In a 1905 paper, Einstein demonstrated how matter could absorb and emit light energy, the energy of photons, and he provided a theoretical explanation for the photoelectric effect. That work would form the basis of Einstein’s 1917 paper where he proposed that a photon of energy, or light, might be emitted by excited atoms - the laser effect.

Today, the treatment of diabetic retinopathy to prevent blindness is one of the leading applications of lasers in ophthalmology. Just half a century ago, a diagnosis of diabetic retinopathy meant you would probably end up blind. It was just a matter of when. Due to lasers alone, diabetic retinal disease, and for that matter a number of retinal and ophthalmic conditions such as retinal tears, detachments, tumors, and glaucoma, are no longer the threat to eyesight they once were. The laser has truly been a remarkable vision of science and ophthalmologists continue to explore new possibilities for its use even today.

When a patient with diabetic retinopathy presents with loss of vision, lasers can be very helpful in recovering lost vision and minimizing the progression of disease. Depending on the extent and type of treatment required, an anesthetic shot and multiple treatment sessions may be necessary. The treatment is often done right in the doctor's office, takes no more than 15-20 minutes and you can go home the same day - and if the patient takes good care of their blood sugars and health, it has a very good chance of limiting disease progression

The intellectual quest that led to the realization of Einstein's seminal 1917 thesis in the laser and its subsequent application in the treatment of eye diseases makes for one of the truly remarkable stories of the 20th century and modern medicine . . . but that's a story for another blog.

Diabetic Retinopathy

2007-12-24T19:08:00.000-08:00

Today, diabetic retinopathy remains the leading cause of legal blindness amongst working-age Americans. An estimated 29 million Americans age 20 years or older have either diagnosed diabetes, undiagnosed diabetes, or impaired fasting blood glucose levels. One third of individuals are unaware they even have the disease. The hormone in our body that controls the metabolism of sugar is insulin. In diabetics, insulin is either produced in insufficient quantity or does not function properly upon its target tissues. As a result, abnormal sugar by-products accumulate throughout our body with damaging effects. The longer one has diabetes the more likely they are to develop its complications, and, as previously mentioned, one of the more commonly affected tissues is the retina. Diabetic retinopathy can be one of the most debilitating aspects of long standing diabetic disease. In patients lacking resources, or those who have not been able to control their disease or receive timely treatment, blindness from diabetes still occurs.

As mentioned, the complications of diabetes result from the effects of abnormal blood sugar metabolism on our body, particularly wherever it has small blood vessels. As the duration and extent of diabetic disease grows, especially in light of poor control, these blood vessels become incompetent. Retinal vessels in particular can become abnormally dilated with the tendency to leak fluid, and this results in swelling of the retina, known as macular edema, with the resultant loss of vision. Alternatively, the retinal vessels can close off completely causing ischemia - a lack of oxygen and nutrient perfusion. Ischemia leads to the development of abnormal new blood vessels which have a tendency to bleed and form scar tissue, and these in turn can cause retinal detachments and even total blindness.

First, take a look at this normal retina, you'll see the normal blood vessels with their branches, the orange appearing retinal tissue, and the optic nerve, the yellow circle which carries the visual signal from the retina to the brain.

Figure Coutesy of the National Eye Institute, National Institutes of Health

Now have have a look at this video. What you see here is actually a fluorescein angiogram of a patient with diabetic retinopathy. An angiogram is a sequence of pictures, in this case a movie, of the retina taken after a fluorescent dye is injected in to the patient's blood stream. If you look closely, you'll see the normal large blood vessels of the retina fill as the dye passes int to the retina's circulation but, more importantly, you'll begin to see it leak out of microaneurysms (the tiny little dots) and abnormal neovascular blood vessels. Leakage from microaneursysms causes macular edema and leakage from neovascular blood vessels causes vitreous hemorrhage, or bleeding (in this case, demonstrated by dark shadows obscuring the retina). This patient has both.

Couching

2007-12-20T19:25:00.000-08:00

Couching is a method of cataract surgery, and one of the oldest types of surgery of any type, founded and performed over 2000 years ago by the Indian surgeon Sushruta. It's a technique whereby a needle, often times less than sterile, is inserted in to the eye to displace an aged, cataractous lens. Where practiced, it wasn't very elegant but it often sufficed to clear the patient's view to the outside world - that is, if the eye survived the operation. Couching has a fascinating history and those who have been blinded under its knife include the likes of Johann Sebastian Bach (who might have died as a result of it) and George Friederich Handel, and Rembrandt even made artistic studies of it in his Tobias series.

Couching is still practiced in many parts of the world today and not too long ago one of my surgery professors showed me this video of a contemporary couching procedure . You'll need a strong stomach to view it, but I am sure you'll have a better appreciation of modern sterile surgical technique after you're done.

If you want to learn more about couching, I suggest you read the chapter on cataract surgery in the conveniently recommended book, Eyes on Ice & No Blind Mice.

Food Porn & Diabetes

2007-12-19T18:00:00.000-08:00

The Nutrition Action Healthletter, a regular publication of The Center for Science in the Public Interest (CSPI), is the largest-circulation health newsletter in North America. Every month, on its back page is a very entertaining and enlightening section titled "Food Porn" - and with a provocative picture to boot! Well, it just so happens that on more than one occasion the not so very coveted Food Porn of the Month Award has gone to Starbucks. One monthly winner, the Coconut Crème and Vanilla Crème Frappuccinos, were found to pack 870 calories and an entire day’s worth of saturated fat into a 20-ounce venti drink, and depending on how you configure your Starbucks drink, 40 to 60g of sugar. I point out Starbucks here since all our children school kids seem to be finding the local barrista a popular hangout but there are a number of such award winners.

Now, with an average daily calorie intake of 1900 or so recommended for women and 2500 or so for men and with a recommended daily sugar intake of 40 grams, one can see where with a frappuccino here, a donut there, and something somewhere else, one might be headed for trouble. I see a great deal of diabetic retinopathy in my practice. Diabetes is becoming quite the epidemic in this country. Of course, many of us can conveniently blame a genetic predisposition, but a lot of it has to do with our tendency to eat a lot and exercise very little. Certainly, the sugar-loaded frappuccinos, sodas and processed drinks we consume in lieu of water don't help either. In the premodern era, we were forced to walk everywhere and there were many times we as humans weren't getting more than a meal a day, much less Starbucks, so we weren't as apt to develop diabetes.

Broadly classified, there are two types of diabetes. Type I is what some folks get at a young age because they can't produce insulin, the hormone that control our body wide sugar metabolism. Type II is what some of us get later in life, due to a dysfunction of whatever insulin we have. Take your typical American living somewhere where he doesn't have - or want - easy access to a gym, takes a car everywhere, spends all day sitting in the office, and then comes home and glues him self to his TV or Tivo, all the while eating high calorie foods. There you have it, the perfect setup for developing Type II diabetes. Basically, the lack of muscle and excess fat mass effectively decrease his insulin sensitivity and ability to metabolize sugars and his chronic overeating of the wrong foods burns out his pancreas, the organ that produces insulin. Early on, those of us who seem to be at risk of or have developed the early signs of diabetes can avoid progression of the disease and the need for medications by changing lifestyle habits, exercising and developing muscle mass, but I rarely see this happen. I read somewhere that most doctors figure patients won't follow exercise and lifestyle/diet advice and hence they go straight to diabetes medications. I also read a study somewhere that they were right. Personal experience as a physician who advocates lifestyle choices confirms this observation - patients generally don't want to make such changes.

Now, as children are drinking sodas at school we're seeing diabetes develop earlier. In either case, Type I or Type II, controlling our blood sugars (and for those of us who are older, our blood pressure and lipid levels) are important in slowing the progression of diabetes. Diabetes generally attacks and damages the small blood vessels in our body, hence patients with diabetes tend to develop problems with their nerves, kidneys, heart, brain, reproductive systems, and retinas - everywhere where small blood vessels are important.

If you have diabetes in your family, or you're overweight, or you may have just developed diabetes, you should be watching what you eat and exercising. That way, you can save yourself a lot of grief. The CSPI, www.cspinet.org, has been an advocate for nutrition and health, food safety, alcohol policy, and sound science. Check out the newsletter and this month's food porn at www.cspinet.org/nah/index.htm. My advice readers, exercise daily and watch what you eat, especially if you have diabetes.

Anatomy

2007-12-18T16:17:00.000-08:00

Why has not man a microscopic eye?
For this plain reason,—man is not a fly.
- Alexander Pope, Essay on Man

Today I plan on introducing you to the basic anatomy of the eye. Since I'll be blogging about the eye and its structures here - and since many of us are less than comfortable with the anatomy of the eye - I thought this would be a good exercise early on.

Let’s begin this blog by thinking of the eye as a camera. Like a film camera, light enters the eye from the outside world where it is focused, captured and seen. Simple? Perhaps, but this is, in fact, a very good model for how the eye works and sees. Now, in truth, the eye is a remarkably complex biological entity that takes part in many essential functions besides just sight alone, but this simple analogy serves as a starting point for appreciating the eye, its diseases and therapy, and the biological process of vision.

Figure Courtesy of the National Eye Intitute

At the very front of the eye are its focusing “lenses.” As a matter of fact, the eye has two of them - the cornea externally and the crystalline lens internally. These “lenses” draw in and focus light and images from the world around us. Although the cornea remains fixed, the crystalline lens changes shape and thus focal length readily, like the auto focus feature of a modern camera, and this enables us to see objects at varying distances from the eye clearly. The cornea and crystalline lens are separated by the iris, the ring-shaped tissue that gives us our characteristic eye color. The iris constricts and dilates, like the variable aperture of a camera, and this regulates the amount of light entering our eye. Ultimately, light is captured at the back of our eye on the retina, our “biological film,” and sent by agency of the optic nerve to the brain where it is processed and the visual image seen. Whereas in a camera the internal spaces are empty, those in our eye are not. Instead, they are filled with clear bodily fluids, the aqueous humor between the cornea and lens and the vitreous humor between the lens and retina (and by the way, its the natural aging of the vitreous humor which gives us those bothersome floaters). And as all of these tissues are part of a living, breathing, human being, they are nourished by blood vessels and directed by nerves.

These anatomical structures constitute the integral elements of our biological cameras. Unlike conventional cameras, which nowadays come with lengthy warranties, our biological ones come with no such measure of protection . Even the smallest flaw can impact our ability to see, so we must learn to care for what we have been given and to work with what we have

Introduction

2007-12-17T20:42:00.000-08:00

Good Day Readers! This blog will be unlike any other that you have come across. As a retinal surgeon, I have had the good fortune of treating a number of magnificent patients and disease conditions and I plan to share some of that experience, and my expertise, with you here. Of course, I'll be waxing on a number of other topics from medicine and science to literature, art, and history since I am a firm believer that there is a lot more to medicine than just medicine alone. I have had a lot of fun writing and publishing my first book, Eyes on Ice & No Blind Mice, and I believe you'll have just as much fun reading my entries here. Check back frequently for some amazing pictures and videos that I have collected and from active clinical cases. I hope the website will be entertaining and educational and, of course, HIPAA compliant.