Eye Conditions Learning Center
Thank you for trusting your care to The Eye Institute of West Florida. In our eye conditions learning center, We have compiled descriptions of various eye conditions and treatment options that patients and their family members are often curious about when making decisions about their care.
You can find educational graphics, information on specific types of technologies and summaries of what patients can expect. These articles serve both patients and health care providers. If there is any information you do not understand, give us a call.
Our physicians routinely speak at industry conferences and train residents, ophthalmologists, and surgeons on the latest techniques.
If you do not find the information you are interested in, contact us so we can help.
- Age-Related Macular Degeneration
- Cystoid Macular Edema
- Diabetic Retinopathy
- Flashes, Floaters, Retinal Tears, and Retinal Detachment
- Fuchs’ Dystrophy
- Macular Holes
- Refractive Errors
- Strokes of the Retinal Veins
- Wrinkled Retina
Retina / Eye Anatomy
The retina is a very thin tissue lining the back wall of the eye that is connected to the brain. The outer part of the retina is nourished by a single special layer of cells called the retinal pigment epithelium that lies underneath the retina like a pad under a carpet on the floor. The transparent cornea and lens in the front of the eye focus incoming images onto a central area of the retina called the macula. The retina converts these images into a chemical message that is sent to the brain. The macula is about 1/4 inch in diameter and is where incoming light is focused. The macula is the only part of the retina which allows you to read the small print and perform visual tasks that require fine or “central” vision. The retina outside of the macula is responsible for the “side” or peripheral vision.
Facts about Macular Degeneration
The macula is the portion of the retina affected by Age-Related Macular Degeneration (ARMD). The disease is termed “age-related” because it only occurs in patients older than 50 years of age. Age-related macular degeneration is the leading cause of severe visual loss in patients over the age of 65 in the United States. Approximately 16 million people in the United States suffer from ARMD. Every year, an estimated 250,000 people in this country will develop severe visual impairment in one or both eyes from ARMD. The exact cause of macular degeneration is unknown. Many factors have been studied to determine why some people develop macular degeneration while others do not. Recently, a defect in the complement factor H gene has been implicated as the single most important risk factor in the development of ARMD. Having this genetic defect raises the risk of developing ARMD to 70%. In addition, people with fair skin and blue eyes are much more likely to develop ARMD. Lifelong exposure to sunlight may be a risk factor. Therefore, patients who spend a lot of time outdoors should wear sunglasses with an ultraviolet protective coating. Cigarette smoking and high blood pressure increase the risk of developing more severe macular degeneration.
Forms of Macular Degeneration
Age-Related Macular Degeneration occurs in two main forms: a “dry” or atrophic type and a “wet” or exudative type. Everyone with macular degeneration initially has the dry form and every person with macular degeneration develops the disease in both eyes, however, one eye can worsen more quickly than the other. The dry form of ARMD is NOT one disease; there are four major groups of dry ARMD. The first three are classified by the size of the small yellow spots (called drusen) that develop in the layer of cells underneath the retina. Drusen come in three sizes: small, medium and large. Patients with small drusen have an excellent chance of keeping good vision during their lifetime. Patients with medium or large drusen have a much higher chance of developing the wet form of macular degeneration, especially if their drusen are associated with small clumps of brown pigment. Patients with medium or large drusen are considered to have “HIGH-RISK” dry ARMD. The fourth type of dry macular degeneration is called geographic atrophy, in which the cells underneath the retina slowly wither away. Geographic atrophy only rarely changes into wet macular degeneration, however, it can cause a person to become legally blind if the disease affects the cells underneath the very center of the macula.
What Is Astigmatism?
Astigmatism is a condition where the cornea is not perfectly round but is oval-shaped, causing blurred vision. Rather than having a symmetrical, circular cornea shaped like a basketball, patients with astigmatism have a slightly oblong cornea shaped more like a football. It is curved differently from one side to the other. Because this bends light rays entering the eye unequally, there is a distortion of the image on the retina, resulting in blurred vision. Uncorrected astigmatism causes ghosting or shadowed images.
What is a Cataract?
A cataract is the clouding of the natural lens inside the eye. While cataracts can develop at any age, for most of us cataracts are a normal part of growing older. In addition to age, smoking, diabetes, past eye infections, injuries or surgery, some medications (such as steroids) and exposure to the sun’s ultraviolet light have been shown to increase the risk of developing cataracts. Symptoms are usually subtle at first, but as a cataract develops (the lens becomes cloudier) you may experience blurred vision, difficulty reading, glare, halos around lights (especially at night), decreased the ability to appreciate vivid colors and frequent changes in your eyeglass prescription. Many people notice a diminution of vision and just think their glasses need changing.
What is Cystoid Macular Edema?
The term “cystoid macular edema” is applied to a specific condition that may have several possible causes. We use “cystoid” in the name because small cysts or “bubbles” form in the retina. These cysts are filled with “edema” fluid that leaks from the retinal blood vessels. It is the same kind of fluid that can cause swollen ankles or fluid in the lungs in a patient with heart failure. Finally, the name contains the term “macular” because of the bubbles of fluid form in the macula, that center part of your retina that is so important for good vision.
Two Forms of Diabetic Retinopathy
There are two main forms of diabetic retinopathy that can potentially cause loss of vision: macular edema and proliferative retinopathy. Macular edema occurs when the damaged small blood vessels in the macula begin to leak protein-filled fluid into the retinal tissue. This fluid is like the fluid that causes ankle swelling in patients with heart failure. When macular edema is present, the retina is swollen. Initially, the patient may not notice any change in vision; however, the eyesight will gradually diminish if the fluid remains in the macula. If macular edema is not treated, the retinal cells will be permanently damaged and vision cannot be restored.
In proliferative diabetic retinopathy, the blood vessels supplying the retinal tissue become so damaged they lose the ability to adequately nourish the retina. The eye responds to this situation by increasing the production of vascular endothelial growth factor (VEGF) which starts the process of growing new blood vessels.
Unfortunately, these new blood vessels grow or “proliferate” (hence the term proliferative retinopathy) along the surface of the retina and do not actually meet the need for more nourishment of the retina. The abnormal new blood vessels can cause two major problems leading to loss of vision. They are very fragile and can easily break, causing a hemorrhage into the large cavity in the back part of the eye. The blood vessels can also eventually form large sheets of scar tissue that can pull on the retina and lead to a retinal detachment. These two problems often have to be corrected by advanced microsurgery performed in the operating room.
Flashes and floaters are very common symptoms experienced by patients. However, they can also be symptoms to a more serious problem of retinal tears and detachments. If you are experiencing an onset of flashes and floaters this is considered an emergency.
Until about the age of 30 years, the vitreous gel has the consistency of raw egg whites. After age 30, the gel undergoes a slow degeneration during which pockets of saltwater from inside the gel and it starts to sag. Eventually, so much water forms inside the gel that it cannot support itself anymore and the structure collapses. The collapse of the vitreous gel is called a vitreous detachment. Small bits of collapsed vitreous gel are now free to “float” around inside the eye. Because the gel now lies in front of the retina instead of being attached to the retina, the light coming into the eye casts tiny shadows from these bits of gel and we see them as floaters.
Flashing lights often occur during a vitreous detachment because the vitreous near the front part of the eye remains connected to the retina. When the gel sloshes around inside the eye as it moves normally, the vitreous that is still connected can tug on the retina. You perceive this tugging of the gel on the retina as flashes of light. There is no pain sensation associated with flashes of light from a vitreous detachment. Sometimes, people with migraines have the sensation of flashing lights. However, these lights which after look like jagged lines, are not associated with floaters, and often occur just before a severe headache.
RETINAL TEAR AND DETACHMENT
In some people the vitreous gel tugs so much on the retina it causes a tear or hole to form in the retina. In many of these patients, the saltwater that is now free inside the eye can go through the hole and cause a retinal detachment. Therefore, it is imperative that all patients who experience flashes and floaters have a detailed examination of the vitreous and retina by a retina specialist who is an expert in this area.
The main symptom of a retinal detachment is the sensation of a “curtain” coming across the field of vision from the side toward the center. The curtain gets progressively larger over several hours or days. As the detachment reaches the center of the retina (the macula), the vision becomes very blurry, often preventing the patient from seeing anything other than fingers in front of their face. The curtain can come from any direction (left, right, top or bottom) and is related to which part of the retina detaches first. There is often a sensation of waviness, as the retina undulates because of the fluid underneath it. The flashing lights and floaters will persist during this time. A retinal detachment is a true emergency and needs to be treated as soon as possible; ideally, before it reaches the macula. Once the macula detaches, and depending upon how long it is detached, the likelihood of regaining normal vision in the eye is significantly diminished.
Patients, who are at a higher risk of getting a retinal detachment, include: people who are very nearsighted, those who have had a retinal hole or detachment in the other eye, or who have a family history of retinal detachment.
Fuchs’ dystrophy is an abnormality in the inner layer of the cornea. It is a slowly progressing disease that usually affects both eyes. It is slightly more common in women than in men and can be seen as early as age 30 to 40. However the disease rarely affects vision until people reach 50 to 60 years old.
Fuchs’ dystrophy occurs when the cells that pump fluid out of the cornea (the endothelia cells) gradually deteriorate. As more endothelial cells are lost over the years, the endothelium becomes less efficient at pumping water out of the corneal stroma (the middle layer of the cornea). This causes the cornea to swell and distort vision. The thickness of the cornea can be evaluated through paschymetry.
Early on in Fuchs’ dystrophy, a patient may awaken with blurred vision that will gradually clear during the day. This occurs because the cornea is normally thicker in the morning; it retains fluids during sleep that evaporate in the tear film while we are awake. As the disease worsens, this swelling will remain constant and reduce the vision throughout the day. As the disease progresses, it is possible that the superficial layer of the cornea (the epithelium) can retain fluid, resulting in pain, blurred vision and an increased risk of infection.
When the disease interferes with daily activities, a person may need to consider having a partial thickness corneal transplant to restore sight. Dr. Neel Desai is one of 100 surgeons worldwide specifically trained on the advanced partial thickness corneal transplant procedure called DSAEK (dee-sek).
Call our office today for a consultation with Dr. Desai or e-mail your request and we will be glad to reach you for an accommodating appointment.
Glaucoma is a general term used to describe a group of diseases of the eye, all having the common characteristic of pressure within the eye greater than the eye can sustain in order to remain healthy. What exactly is this “pressure”? In the front part of the eye, there is a watery fluid which keeps the eyeball firm and clear. Under normal circumstances, this fluid constantly flows into and out of the eye keeping a perfect balance between the fluid made and the fluid drained out of the eye through tiny veins. In glaucoma, for some reason, the outflow of this fluid is blocked, and this causes the increased pressure. When the pressure gets too high, it can cause damage to the delicate optic nerve in the back of the eye which is responsible for carrying visual images to the brain. Often, glaucoma has no symptoms and can result in vision loss. Without proper treatment, glaucoma can lead to blindness. The good news is that with regular eye exams, early detection and state-of-the-art treatment, vision can be preserved.
Understanding How the Eye Works
A macular hole is a fairly common problem among adults. In order to understand what causes macular holes and how they are treated, it is important to learn about the structure of the eye. The eye is shaped like a small egg and measures about one inch across. The cornea and lens, which lie in the front part of the eye, focus incoming light to form an image on the retina. The retina lines the back wall of the eye and, like the film in a camera, functions to capture images and transmit them to the brain. The central area of the retina where the light is focused is called the macula. The macula allows 20/20 vision and is responsible for reading and other tasks that require fine discrimination. Between the lens of the eye and the retina is a large round space called the vitreous cavity. This space takes up 80% of the volume of the eye and is filled with a transparent gel called the vitreous humor. This gel is normally transparent and is attached to the inner surface of the retina.
The Nature and Causes of Macular Holes
In most people between the ages of 60 and 70 years, the vitreous gel collapses and causes floaters. In some people, the gel is abnormally firmly attached to the retina, especially in the area of the macula. In these people, the vitreous gel can begin to pull on the macula instead of separating away from the retina and cause a small hole to form in the center of the macula. You can demonstrate what happens inside the eye by holding a facial tissue in both hands and slowly pulling it apart until a hole forms in the tissue. In most patients with a macular hole, there is also a fine layer of scar tissue on the surface of the retina that may also pull on the edges of the hole.
Symptoms of Macular Holes
The symptoms that you may experience from a macular hole include blurry vision while reading or driving, loss of depth perception, distortion of lines that are supposed to be straight, or a blank area in the center of the field of vision. These symptoms may progress gradually or appear over several days or weeks. Macular holes affect both eyes in about 1 of every 10 patients, although one eye may be worse than the other and both eyes are not usually affected at the same time. Another way to say this is that if you have a macular hole in one eye, there is about a 15% chance of developing a macular hole in the other eye. The best way to monitor vision is to look at the Amsler Grid once or twice a week. It is important to understand that many people who develop a macular hole may be unaware of the change in their vision if they do not check one eye at a time by covering the other eye; this is the reason we ask you to check the Amsler Grid one eye at a time.
Learn How the Eye Works
The precision with which the eye focuses on objects is partly determined by the shape of its cornea. This process is called refraction. Just as a camera’s parts serve to focus light rays on to the film to produce a clear and vivid image, the structures of the eye similarly function to focus light and images. As light rays make their way into the eye, they must first pass through the tear film and the clear cornea getting focused, or refracted, along the way. Light rays then pass through the pupil, which acts like a camera shutter, and then through the internal lens of the eye where it gets further focused. Ideally, after passing through these optical elements, light rays will land on the retina in the back of the eye in perfect focus. The retina, like the film inside a camera, translates these light impulses into electrical impulses that are delivered to the vision centers of the brain via the optic nerve.
What is Refractive Errors
In an ideal world, the cornea’s shape and curvature would be perfectly smooth and spherical, like a basketball symmetric in all directions. We do not, however, live and function in an optically ideal world. Instead, all of us have unique optical traits or aberrations that result in refractive errors. For many of us, these refractive errors create blurred vision and the need for glasses, contact lenses, or corrective surgery.
Nearsightedness, Farsightedness, Astigmatism & Presbyopia
There are many different types of refractive error that relate to the unique shape differences in the cornea. Nearsightedness, or myopia, results from a cornea that is too steeply curved, relative to the ideal, such that it focuses light too strongly and creates an image focal point in front of the retina. Nearsighted patients can focus on an object held close up but cannot see clearly in the distance. Conversely, farsightedness or hyperopia results from a cornea that is too flat relative to the ideal, causing it not to refract enough light. Because with hyperopia the theoretical focal point is beyond the retina, farsighted patients cannot see clearly at near-range or intermediate-range, and often need correction for distance as well.
Astigmatism refers to yet another unique aberration in the shape of one’s cornea versus the ideal. In an eye with astigmatism, the cornea takes on an oblong shape more like a football than a basketball; more steeply curved in one direction and more flat in the other direction. As one might imagine, light passing through a cornea with astigmatism is not normally focused and produces an image that is blurred and often accompanied by ghost-images, shadowed images, or double images.
When we approach the age of 40 to 45, the internal lens of the eye no longer retains the flexibility of a youthful lens, and hence is unable to adaptively change its power to accommodate to varying ranges of focus. This natural and progressive process is called presbyopia and is a form of refractive error heralded by the common need for magnifiers or bifocals for reading.
Treatment Options for Refractive Errors
Prescription glasses or contact lenses can correct most simple refractive errors; however, more severe cases aren’t so easy and may require the specialized skills of a cornea-refractive surgeon. Fortunately, using the most sophisticated techniques and cutting-edge technologies available at only a few exclusive centers in the world, our physicians can safely correct all types of refractive errors and restore the youthful vision our lifestyles demand.
A number of treatment options are available for your unique needs. While only a detailed consultation with your surgeon at the Eye Institute of West Florida can definitively determine what option may be best for you, our physicians specialize in, and in many cases have pioneered the techniques to help you. These options may include laser refractive surgery, such as LASIK, which involves a custom laser-guided reshaping of the cornea to correct your unique refractive error and eliminate the need for glasses or contact lenses. The Eye Institute of West Florida also specializes in advanced lens implants that are capable of eliminating refractive errors such as nearsightedness, farsightedness, astigmatism, and presbyopia, so patients can achieve greater independence from glasses or contacts than ever before. Several lens-based options exist including astigmatism-correcting lens implants and a variety of lens that restores a youthful range of vision to the eye, including the Crystalens™, the Restor™ Lens, and the Tecnis Multifocal™ lens. The Eye Institute is also proud to be one of a few elite centers in the world to pioneer the use of wavefront technology, borrowed from the NASA Hubble Space Telescope, in the operating room. This technology, called the WaveTec ORange™ intraoperative aberrometer, allows Dr. Weinstock and Dr. Desai to capture unique optical fingerprint maps of your optical system and surgically correct astigmatism with the greatest precision and accuracy.
See Our Experts
Whether exploring options of laser refractive surgery, such as LASIK, or other options such as advanced lens implants, your Eye Institute surgeon will help you choose the best and safest procedure to meet your individual needs. As our Cornea, Cataract, and Refractive Specialist, Dr. Stephen Weinstock, Dr. Robert Weinstock and Dr. Neel Desai share the Eye Institute philosophy and firmly believe that there is no one-size-fits-all option for every patient. Instead, patients are assured in knowing that, in course of a one-on-one consultation, he will bring to bear all the technologies, techniques, and expertise needed to find a completely customized option for each patient in order to deliver the most optimal outcome.
Please call our office and ask to see one of our expert refractive specialists for a consultation to explore all your treatment options.
Strokes are usually associated with a blockage of blood flow to a part of the brain. Strokes can occur in the eye, and are in fact a very common problem treated by retina specialists. In order to understand this problem and how it can be treated, it is important to first learn about the structure of the eye.
Anatomy of the Eye
The eye is shaped like a small egg and measures about one inch across. The cornea and lens, which lie in the front part of the eye, focus incoming light to form an image on the retina. Between the lens of the eye and the retina is a large round space called the vitreous cavity. This space takes up 80% of the volume of the eye and is filled with a transparent gel called the vitreous humor. The retina lines the back wall of the eye and, like the film in a camera, functions to capture the incoming light and transmit an image to the brain. The central area of the retina where the light is focused is called the macula. The macula allows 20/20 vision and is responsible for reading and other tasks that require fine discrimination. If a disease affects the macula, the center part of the vision may become blurry and distorted. If a disease affects the retina outside of the macula, the “side” or peripheral vision may be decreased.
Like most parts of the body, the retina is supplied with two sets of blood vessels called arteries and veins. The arteries carry blood, oxygen, and nourishment to the retina and the veins drain the blood and waste products away from the retina. The arteries and veins of the retina are like a tree: they have a main “trunk” (called the central retinal artery or vein) and many smaller branches (called the branch retinal arteries or veins).
A stroke of the retinal veins may affect either the main trunk of the blood vessels (this is called a central retinal vein occlusion) or one of the smaller branches of the vein tree (this is called a branch retinal vein occlusion). Usually, there is no pain associated with the stroke and the vision is lost suddenly. The part of the vision that is lost depends on the size of the vein that is affected by the stroke, the amount of the retina that is supplied by the affected vessel and whether the macula is involved. The amount of vision loss may vary from almost none to almost all.
When a stroke of a retinal vein occurs, the blood that is normally carried away from the retina can’t get out because the passageway is blocked. This is like having the drain in your sink clogged while leaving the faucet running: soon the water will fill up in the sink and spill out onto the floor. The blood from the vein spills out into the retina and causes bleeding into the retina and swelling of the retina. The blood and swelling may gradually go away after many months, but will cause damage to the retinal area affected by the stroke.
Cause of Retinal Strokes
After Dr. Kirsch or Dr. Hairston diagnoses a stroke of the retinal vein, he will try to determine whether any diseases may have contributed to causing the stroke. Glaucoma is the most common eye disease associated with vein occlusions. Your family doctor will be contacted to set up an appointment so you can get a thorough general physical examination. The most common medical diseases associated with strokes of the retinal veins are high blood pressure and diabetes. There are many less common diseases that may be related to these strokes; we will direct your family doctor to look for these if there is a possibility that you may have one of these conditions.
A Pterygium (pronounced tur-IJ-ee-um) is a benign fleshy tissue growth that extends from the white conjunctiva of the eye towards the center of the cornea, the clear window of the eye. These growths are most common in the sun-exposed areas of the eye not protected by the eyelids.
The appearance of a pterygium can vary from a small tissue mass to a large, red, and irritating growth. Your eye doctor will be able to help you distinguish a benign pterygium from other more concerning cancerous or pre-cancerous growths on the eye.
A wrinkle in the retina is a very common problem among older adults. In order to understand what causes this problem and how it can be cured, it is important to learn about the structure of the eye.
Anatomy of the Eye
The eye is shaped like a small egg and measures about one inch across. The cornea and lens, which lie in the front part of the eye, focus incoming light to form an image on the retina. The retina lines the back wall of the eye and, like film in a camera, functions to capture and to transmit images to the brain. The central area of the retina where the light is sharply focused is called the macula. The macula allows 20/20 vision and is responsible for reading and other tasks that require fine discrimination. Between the lens of the eye and the retina is a large round space called the vitreous cavity. This space takes up 80% of the volume of the eye and is filled with a gel called the vitreous humor. This gel is normally transparent and is attached to the inner surface of the retina.
How Wrinkled Retina Occurs
Until a person is about 30 years of age, the vitreous gel has the consistency of raw egg whites. After age 30, the gel undergoes a slow degeneration during which pockets of saltwater from inside the gel and it starts to sag. Eventually, so much water forms inside the gel that it cannot support itself anymore and the structure collapses. The collapse of the vitreous gel is called a vitreous detachment. When the vitreous detaches, it can cause, among other things, microscopic damage to the inner surface of the retina, especially in the macula. The retina heals itself by the migration and proliferation of certain cells that normally are found within the retina. In most people, the healing process occurs without any further problems, but in some people, the healing process goes “haywire” and results in the formation of scar tissue along the inner surface of the retina. This scar tissue is called an epiretinal membrane.
Once the scar tissue forms, several things can happen. For most people, it grows very slowly and eventually stops. However, in some patients, the scar tissue continues to grow and begins to pull on the retina. When the scar tissue pulls on the retina, the retina becomes wrinkled. So instead of the retina having a smooth surface like the bottom of a glass bowl, it looks like a ruffled potato chip.