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I. Von Hippel-Lindau
What is Von Hippel-Lindau (VHL)?
Von Hippel-Lindau (VHL) is a hereditary disease caused by a flaw in a tumor suppressor gene that regulates cell growth. VHL causes blood vessels to sprout up as tumors in the eye, the spinal cord, and the brain, especially in the cerebellum.
In 1904 a German ophthalmologist Eugen von Hippel first described angiomas, or blood vessel tumors, in the eye, and in 1924 Arvid Lindau described angiomas of the cerebellum and spine.
VHL occurs in approximately one in 36,000 births and it is listed as a rare disease. The average age of diagnosis is 26, however tumors may be present at birth and may begin growing well into old age.
How does it affect patients?
The longer VHL patients live, the more likely a tumor will appear. Patients with VHL live daily knowing at some point a headache or a funny heartbeat may be a tumor that threatens their functioning, their independence, their dreams and their very lives.
Many of these patients know first hand what will happen, as they often have fathers, mothers, brothers or sisters who go blind, have an open craniotomy or a surgery to remove an abdominal cancer. They have seen family pass away from VHL, often after multiple tumors and surgeries throughout their body.
What is treatment like?
The retinal specialists will laser or freeze the vascular tumors formed in the retina by the VHL.
If a tumor is found it is often lasered. Other times it is treated with injections of antivegf medicine to stop the tumor growth, a treatment that was developed in the last decade. These treatments can also be combined.
Sometimes the patient will develop a retinal detachment and a vitrectomy--a removal of the eye’s gel and scar tissue from the tumor-- is required. A bubble of oil or gas may be injected to help keep the retina attached. After this procedure the patient must keep their head pointed to the ground so that they heal properly.
Some VHL lesions in the retina are inoperable at presentation, or carry a poor prognosis into surgery. Even after surgery, when the retina is initially successfully attached, the retina can redetach post operatively.
With or without operation, the eye can shrink or become scarred. If this occurs, patients can visit an ocularist to fashion a prosthetic eye by using pictures and molds to match the other eye and eye socket.
What is the latest in treatment technology?
Photodynamic therapy (PDT) is a new type of laser treatment that allows us to directly treat some of the smaller and medium-sized tumors near the optic nerve. Injections of antivascular endothelial growth factor (antivegf) directly into the vitreous cavity (the jelly of the eye) may shrink vascular tumors in some cases. Some retinal surgeons combine the two, but these are still primitive weapons in treating VHL.
Scientists have discovered a tumor suppressor gene on chromosome 3 that appears to be the cause of VHL. This knowledge may one day lead to genetic treatment and a cure.
Until then patients, doctors, and families battle on.
How did VHL affect Damian?
In Damian’s situation, he lost all the vision in his right eye starting at 11 years old, definitively ending his dreams of being in the air force and an astronaut. A healthy child with both parents may find visits to the doctor for strep throat or ear aches to be extremely stressful. Imagine sitting alone with an oncologist at the tender age of 11 and finding out tumors are growing in your eye, blinding you.
In response patients often develop an active psychological mechanism to prepare for extreme challenges.
****Note - (NEEDS more explanation of how it affected him physiologically and psychologically) and (add into Damian’s story or cut altogether) ***
What was treatment like for Damian?
In Damian’s case the tumor originated and was part of the optic nerve, the main cable that is filled with nerve fibers that transmit all the visual information to the brain to see. Lasers used at that time could not be used to laser the tumor as it would heat and destroy the optic nerve. The tumor can also bleed into the vitreous gel, and may leak fluid into the retina, which being an electrical network, short circuits with fluid and will be severely damaged by blood from the growing tumor.
(put in line with Damian’s story, split into treatment if necessary)
“A special kind of patient needs a special kind of doctor.”
II. Diabetes Mellitus
Why is diabetes so common, and why are its effects so severe?
Diabetes remains the most common cause of blindness in the United States in young to middle aged adults for three main reasons:
Diet: Controlling diet is difficult.
False optimism: Most patients believe they have a milder type of diabetes early on, but it advances to affect the body’s blood circulation, which damages the kidneys, eyes, brain and heart.
Delayed effects: Patients feel no ill effects for years while their sugar is out of control. Only much later will the damage manifest as complications in health.
The delay in “punishment” from high blood sugar means that early warning and adjusted diet are essential to prevent diabetes from ravaging the body. Patients must understand that years of high blood sugar caused by poor diet results in blindness, strokes, heart attacks, and loss of limbs.
Sometimes witnessing a loved one succumb to diabetes, experiencing kidney failure, amputation or blindness will cause a patient to improve their diet and blood sugar control. But because the realities of future damage are often not fully understood, patients don’t manage their blood sugar properly. This continues until they experience vision loss, a heart attack, or kidney failure, and though they respond with diet management, the majority of damage has been done and further loss will likely ensue.
How does a disease of increased blood sugar complicate health?
When sugar is too high in the blood it damages the blood vessels. The capillaries-- the smallest blood vessels in the body-- deteriorate over years of poor sugar control. In addition, pericyte support cells that help repair blood vessels die off, accumulating damage over time. Most of the damage is not reversible, although better sugar control usually decreases the severity of the problems.
The nature of the disease carries a momentum that too often runs its course despite medical advice and treatment. Loss of function often occurs during the prime years of a patient’s life, starting as a young adult through their middle-aged years and beyond.
How does diabetes result in vision loss?
Long term blood vessel damage results in the eyes not receiving proper nutrition and accumulating waste that would normally be disposed of. Early changes that appear in the eyes of diabetic patients are called background diabetic retinopathy. These are hemorrhages, small aneurysms, and small infarcts of the retina that can be seen in exams or photographs.
The blood vessels at this stage are like garden hoses that have small holes along their course. These damaged vessels leak fluid throughout their length, where normally they should only exchange nutrients and waste at the capillaries (the end of the hose). These leaks allow blood, cholesterol and watery serum to leak out into the retina. The fluid distorts the shape of the retina and short-circuits the retinal neural network, resulting in loss of vision.
When this happens on the macula, the location of the retina responsible for our center of vision, it is known as macular edema. The irregular pooling of fluid in the macula disrupts a delicate structure vital to normal vision. It is difficult to cure and can last for months to years even with aggressive treatment.
If sugar remains out of control the patients may progress to the next stage called proliferative diabetic retinopathy, which includes bleeding into the vitreous cavity of the eye and “new” growth of fibrous blood vessels from the retina.
(proliferative diabetic retinopathy with large leashes of new blood vessels and white dots from laser treatment [confirm with dad])
These new vessels disrupt the structure of the eye and must be treated. Blood and scar tissue are leftover, and when they are removed vision improves.
Patients with proliferative diabetic retinopathy often lose peripheral vision due to weak peripheral circulation. Some patients develop extensive growth of new blood vessels in the retina which can result in a retinal detachment.
(Severe Diabetic Traction Retinal Detachment confirm with Dad placement in description)
Often despite the physician’s best efforts, the patient continues living with vision loss even after all possible treatment is given.
How is diabetic vision loss treated today?
Treatments for leakage of fluid and macular edema involve light laser to the macula, injection of anti-vegf agents directly into the vitreous cavity of the eye, and injection of steroids around or directly into the eye.
When bleeding occurs in proliferative diabetic retinopathy, heavy laser called pan retinal photocoagulation (PRP) is used to burn the peripheral retina causing the new blood vessels to shrink back. Anit-vegf injections can also be used, but last only 6 to 10 weeks, and need to be repeated frequently to suppress the new growth of blood vessels until laser treatment is possible. Retinal surgeons remove the resulting blood and scar tissue to improve vision.
Almost every tool a retinal surgeon has may be used to treat diabetic retinopathy, and often ophthalmologists combine treatments because complications occur simultaneously.
For the patients that have advanced diabetes, the field of vitreoretinal surgery and other medical treatments continue to grow and evolve.
III. Retinopathy of Prematurity (ROP)
What is prematurity?
When a baby is born before it is fully developed it is considered premature. Mild prematurity is usually not a problem, but in cases of severe prematurity, when the baby is delivered months too early (less than 31 weeks of gestation), or the baby is 1250 grams (about 2.75 pounds), the eyes are at risk for blindness.
How does prematurity of birth result in ROP and vision loss?
During a fetus’s growth in the mother’s womb, its retinal blood vessels normally grow out from the optic nerve to the edge of the peripheral retina. However in retinopathy of prematurity, the blood vessels have not had enough time to grow to the edge of the peripheral retina, so large patches of retina are present without any blood vessels.
This lack of blood flow makes the retinal cells release chemicals for new blood vessel growth. The new blood vessel growth, known as fibrovascular proliferation or neovascularization, causes excessive scar tissue and bleeding that result in vision loss.
If the baby is fortunate their retinal blood vessels fill in the missing peripheral areas naturally, the baby is deemed resolved and no treatment is necessary.
How is Retinopathy of Prematurity Treated?
Treating retinopathy of prematurity requires limiting the growth of new blood vessels. In moderate cases, laser ablation or occasionally cryotherapy (freezing the retina without blood vessels) is utilized to treat the areas of retinopathy. In severe cases close to the macula and optic nerve, antivegf injections are administered to the vitreous cavity of the eye if laser proves insufficient. If those treatment methods fail to stop the growth of new blood vessels, or if the blood vessels have turned into scar tissue and detached the retina, a vitrectomy or scleral buckle is required to try to reattach the retina.
Do people who have had ROP as infants have higher risk of other eye disease as adults?
Unfortunately, even if a premature infant is lucky enough to escape ROP, as an adult they may have issues with their eye muscles (strabismus), cloudy lenses (cataract), high pressure in the eye (glaucoma) or retinal detachments.
IV. Retinitis Pigmentosa (RP)
What is Retinitis Pigmentosa (RP) and how does it progress?
Retinitis Pigmentosa (RP) is a group of genetically inherited disorders affecting the retina. Multiple types of genetic abnormalities can cause RP: a pale optic nerve, narrowed retinal arteries and scattered pigmentation (pigmentosa) throughout the peripheral retina. The name itself is a partial misnomer, as there is no retinitis, or no inflammation of the retina, but the pigment is commonly found at damaged sites of the retina.
“Classic” RP is sometimes called Rod/Cone disease because the rods are affected more severely than the cones. The rods are more abundant in the peripheral retina and are responsible for night vision. Because of this, RP typically begins as night blindness and eventually progresses to peripheral vision loss. The peripheral vision slowly contracts, and when the patients have lost most of their peripheral vision, they are said to have “tunnel vision”. When RP progresses to this stage it is like looking through a straw.
A few patients eventually develop total blindness in their middle age, but most maintain some islands or small pieces of vision for most of their lives.
There are cases in which central vision is lost first. The central vision relies on the area of the retina called the macula, and is predominantly made up of cones. These patients have Cone/Rod disease and are usually diagnosed earlier than “classic” Rod/Cone RP because the loss of central vision warrants greater attention.
In some rare cases RP patients have associated deafness at birth or during childhood, a condition known as Usher’s disease.
Is there treatment for RP?
Presently there is no proven treatment for RP. However, research is showing some promise. But even with recent breakthroughs, the progress is slow. For now, low vision aids, support groups, and supportive family and friends are the present reality for most patients.
One low vision aid device is the Argus II Retinal Prosthesis System (ArgusII), which provides electrical stimulation of the retina to produce some visual perception in individuals with severe retinitis pigmentosa. The implant is surgically implanted on top of the retina. It includes an antenna and an electrode array. The external equipment includes glasses, a video processing unit (VPU) and a cable. Although the images produced are not what a normal person would call reasonable vision yet, in some patients facilitates helpful vision.
The use of stem cells or retinal pigment epithelial cell transplants are another area of active research. These cells are injected into the subretinal space to try to regenerate damaged cells. Although promising, these techniques are still in their primitive stages. Future techniques of gene identification and replacement are likely to be used in younger patients before their retinas are affected by the disease.
V. Leber’s Congenital Amaurosis (LCA)
What is Leber’s Congenital Amaurosis (LCA)?
Leber’s Congenital Amaurosis (LCA) is an inherited retinal disease that causes visual loss in the first months of life. It is inherited as a recessive trait, meaning both the mother and father must have an inactive copy of the gene that they give to the child. When two of the genes are together, LCA manifests. Because LCA is a recessive condition, there is often no family history of the disease, which makes LCA difficult for families to anticipates.
Often, retinal regions affected by the defective genes show up as abnormal pigment on the retina.
An infant with LCA will have nystagmus, or rhythmic movements of the eyes back and forth beginning in the first few months of life. This type of movement occurs in infants that lose vision in both eyes from any disease, and must be distinguished from other possibilities such as congenital cataracts and retinopathy of prematurity.
The retina usually looks normal at this stage.
LCA is actually a group of diseases associated with abnormal photoreceptor cells, so there is variation in presentation and severity.
How do we treat LCA?
Many of the genes that cause LCA have been identified. Once the gene responsible for a condition has been identified, the condition may be treated by gene therapy.
For instance, one type of LCA known as LCA2 was found to be caused by a mutation in the gene RPE65, and it has been successfully treated with gene replacement therapy. A functional copy of gene RPE65 is injected into the subretinal space via a viral vector with a promoter gene sequence. The results have been encouraging, as many patients undergoing the treatment stability of improved vision.
However, this treatment must be done early in the course of the disease before the retinal cells are damaged irreversibly. For those who have grown up with LCA, this is not a viable treatment.
What is glaucoma? What are the types of glaucoma?
Glaucoma is a group of eye diseases that causes damage to the optic nerve and vision loss. After cataracts, glaucoma is the leading cause of blindness worldwide.
Chronic open angle glaucoma is the most common type of glaucoma. Older patients are more likely to develop this type. Abnormally high eye pressure, medically known as intraocular pressure, causes a slow, painless loss of the visual field which can eventually take the central vision and cause total blindness if left untreated.
There are many other less common types of glaucoma, including normal tension glaucoma where the pressure is not elevated, but the optic nerve is damaged. Another type of glaucoma is narrow angle glaucoma, which can be prevented from occurring by having a simple, office laser procedure.
Some patients with diabetes or retinal vascular disease can develop glaucoma due to abnormal growth of new blood vessels. This may reach the surface of the iris and close the drainage site of the eye, causing a sudden extreme increase in eye pressure.
How is glaucoma treated?
Treatment for glaucoma varies depending upon the type, although pressure-lowering drops are commonly used in most forms of glaucoma. If these do not lower the pressure enough, surgery may be required to lower the pressure in the eye.
The key to preventing vision loss for most forms of glaucoma is early detection before the optic nerve becomes irreversibly damaged. Because of this, anyone with a family history of glaucoma should have regular eye exams by an ophthalmologist.
A cataract occurs when an eye’s natural lens becomes cloudy. Cataracts are the leading cause of blindness worldwide, though the condition itself is treatable with modern medicine. Clouding of the lens obstructs vision, and if lead untreated, this obstruction may eventually lead to total blindness.
Most cataracts are due to aging. However, diabetes, steroid use, tobacco, trauma and some genetic diseases may also cause clouding of the lens. Cataracts are treated with surgery, by removing the cloudy lens and replacing it with an artificial one.
What is Coats’ disease, and how does it cause vision loss?
Coats’ disease is a rare retinal vascular disease in which abnormal retinal blood vessels leak fluid and cholesterol into and under the retina.
Coats’ disease affects males almost exclusively, and many of the affected lose significant vision in the eye involved. Most instances of Coats’ disease arise in infants and childhood; adult onset Coats’ is rare. The younger the disease presents, the more severe it tends to be. If the case is severe or the diagnosis is significantly delayed, patients may require a complete removal of the eye. In such cases, the disease leaks so much fluid and cholesterol under the retina that the retina detaches and fills with fluid and yellowish cholesterol crystals. In severe cases, the patient may also develop severe glaucoma.
The affected eye and its vision remain at risk the entire life of the patient, and continued treatment is usually necessary through adulthood. Perhaps the one grace of Coats’ disease is the fact that it is unilateral, meaning it typically only affects one eye.
Unfortunately, this unilateral pattern puts the patient at risk of amblyopia, an eye disorder commonly known as “lazy eye”. When a child under 12 years of age has significant vision loss in predominantly one eye, the developing brain ignores that eye. Due to this neglect, the eye begins to have muscle issues known as strabismus, causing the eye to turn in or out. Though the effect is largely cosmetic, the resulting psychological damage of amblyopia may even surpass the challenges caused by the vision loss itself.
An unsolved mystery of Coats’ disease is why it occurs almost exclusively in males, and only unilaterally. The cause of the abnormal blood vessels remains unknown despite research and genetic advances. Some have proposed a hormonal theory, which remains unproven and doesn’t explain why only one eye is involved. Due to Coats’ tendency to predominantly affect males research has targeted sex chromosomes, but to date no definitive gene has been found.
How is Coats’ treated?
To treat Coats’, lasers are used to cauterize the abnormal blood vessels to stop leakage and allow the retina to dry. In some cases where retinal detachment occurs, surgery may be necessary. Sometimes due to the severity of the disease the eye may be inoperable.
Even if treated using laser, many patients still develop amblyopia or “lazy eye”. In order to keep the afflicted eye from developing amblyopia, patients cover the stronger eye to train the weaker eye. If the normal or better eye is not covered regularly the brain begins to ignore the weaker eye. If this happens for long, amblyopia can become permanent.