Vitreo-Retinal Diseases

Vitreo-Retinal Diseases

What are vitreo-retinal diseases?

A large variety of conditions can affect the vitreous and retina that lie on the back part of the eye that is not readily visible, such as diabetic retinopathy, macular degeneration, retinal detachments or tears, macular holes, retinopathy of prematurity, retinoblastoma, uveitis, eye cancer, flashes and floaters and retinitis pigmentosa.

What are the retina and vitreous?

The retina is an extension of the brain. It forms the interior lining of the eye and contains millions of light-sensitive nerve endings (rods and cones).

The light rays that enter the eye though the cornea, then pass through the pupil, lens and vitreous ultimately focus on the retina which receives the light and transmits nerve impulses through the optic nerve to the brain, where a visual image is created.

Vitreous is a clear, gel-like substance that fills the cavity between the lens and the retina and serves vision by supporting the shape of the eye. 

What are the macula and the fovea?

The central portion of the retina is the macula which provides central vision. The macula is composed of cones and rods. The cones allow us to see in bright light, to distinguish color, and to discern fine detail in reading and the rods are more sensitive to dim light and allow for night vision, but cannot distinguish either color or fine detail. Outside the macula, cones dwindle. The peripheral retina is made up primarily of rods, which provide peripheral vision both day and night. In the center of the macula is the fovea, an area smaller than a pinpoint. It is composed entirely of cones. This tiny piece of the retina provides the sharpest vision --- the vision required to read. Everything we look at directly comes into focus at the fovea. What conditions, diseases and irregularities affect the retina and vitreous?

The retina and vitreous can be affected by a large variety of conditions, including diabetic retinopathy, macular degeneration, retinal detachments or tears, macular holes, retinopathy of prematurity, flashes and floaters, retinoblastoma and retinitis pigmentosa.

What is diabetic retinopathy?

A person with diabetes is at risk for developing diabetic retinopathy among other ophthalmic disorders. Diabetic retinopathy is the leading cause of blindness in young and middle-aged adults today. The longer a person has diabetes, the greater their chance of developing diabetic retinopathy. There are two types of diabetic retinopathy:
  • non-proliferative diabetic retinopathy (NPDR)
  • proliferative diabetic retinopathy (PDR)

NPDR, also known as background retinopathy, is an early stage of diabetic retinopathy and occurs when the tiny blood vessels of the retina are damaged and begin to bleed or leak fluid into the retina resulting in swelling (diabetic macular edema) and the formation of deposits known as exudates. Many people with diabetes develop mild NPDR often without any visual symptoms.

PDR carries the greatest risk of loss of vision and typically develops in eyes with advanced NPDR. PDR occurs when blood vessels on the retina or optic nerve become blocked consequently starving the retina of necessary nutrients. In response, the retina grows more blood vessels (neovascularization). Unfortunately these new vessels are abnormal and cannot replenish the retina with normal blood flow.

PDR may lead to any one of the following:
  1. Vitreous hemorrhage - proliferating retinal blood vessels grow into the vitreous cavity and break down. Both the hemorrhaging and resultant scar tissue may interfere with vision.
  2. Traditional retinal detachment - scar tissue in the vitreous and on the retina cause the retina to detach.
  3. Tractional and rhegmatogenous retinal detachment - scar tissue creates a hole or tear in the retina causing it to detach.
  4. Neovascular glaucoma - abnormal blood vessel growth on the iris blocks the flow of fluid out of the eye causing the pressure to increase and damaging the optic nerve.

What are the symptoms of diabetic retinopathy?

Generally, people with mild NPDR do not have any visual loss. A dilated eye exam is the only way to detect changes inside the eye before loss of vision begins. People with diabetes should have an eye examination at least once a year. More frequent exams may be necessary after diabetic retinopathy is diagnosed. 

People with PDR experience a broader range of symptoms. They may:
  • see dark floaters
  • experience loss of central or peripheral vision
  • experience visual distortions or blurriness
  • experience temporary or permanent vision loss

How is diabetic retinopathy diagnosed?

Diabetic retinopathy is diagnosed by dilating the pupil and looking inside the eye with an ophthalmoscope. If an ophthalmologist discovers diabetic retinopathy, he or she may wish to order color photographs of the retina through a test called fluorescein angiography. During this test, a dye is injected into the arm and quickly travels throughout the blood system. Once the dye reaches the blood vessels of the retina, a photograph is taken of the eye. The dye allows the ophthalmologist to detect damaged blood vessels that are leaking dye.

Can diabetic retinopathy be prevented?

The most effective overall strategy for diabetic retinopathy is to prevent it as much as possible. Strict control of blood sugar levels will significantly reduce the long-term loss of vision from retinopathy. With improved diagnosis and treatment, only a small percentage of people with retinopathy develop serious vision problems.

What are the current treatment options for a person with diabetic retinopathy?

Because the earliest stages of diabetic retinopathy include inflammation, intraocular corticosteroids have been utilized with some success in selected patients. This form of treatment includes the use of a long-acting corticosteroid (triamcinolone acetonide) injected into the vitreous cavity by way of a very tiny needle under topical (drops) anesthesia. This treatment may reduce retinal swelling and improve visual acuity in patients with diabetic macular edema. However, visual recovery may be limited and the effect may last only 3 to 6 months after the treatment.By injecting a VEGF inhibitor inside the eye,the proliferative stage can be slowed down or even stopped if combined with other modalities like argon laser or vitrectomy

Diabetic patients also have a number of non-retinal abnormalities including increased rates of cataract, glaucoma, ocular muscle abnormalities, corneal diseases, and susceptibility to infection.

What is age-related macular degeneration?

In the western world, age-related macular degeneration (AMD) is the leading cause of legal, irreversible blindness among people 50 years of age and older.

    • Dry macular degeneration (atrophic AMD) is the most common form of macular degeneration and can progress to cause severe central vision loss. This disease progresses slowly and most people usually maintain some central vision in at least one eye. The condition always starts as "dry" AMD. "Dry" AMD refers to the slow degenerative process that occurs without any formation of abnormal blood vessels. The recent Age-Related Eye Disease Study (AREDS) demonstrated that the progression of "dry" AMD could be slowed with vitamin supplementation. This study demonstrated the benefits of taking Vitamin C, Vitamin E, beta carotene, and zinc along with copper. Several vitamin preparations containing the appropriate amounts of these vitamins are currently available and we encourage patients with AMD to discuss these various vitamin preparations with their eye care specialist. Previous studies have also suggested that green leafy vegetables may be beneficial and smoking may be detrimental to patients with AMD.

  • "Wet" macular degeneration (exudative or neovascular AMD) is caused by blood vessels growing under the retina in the macula. "Wet" AMD always arises from pre-existing "dry" AMD. These blood vessels leak fluid, protein, lipid and blood. Eventually, if untreated scar tissue forms under the macula and central vision is destroyed. Current treatments approved for "wet" macular degeneration include thermal laser therapy and Anti VEGF injections intravitrealy

What are the symptoms of macular degeneration?

There is no pain associated with dry or wet AMD. The most common symptom of dry AMD is slightly blurred or fuzzy vision requiring greater illumination to see greater details. Also, an inability to recognize faces at a distance may develop.

As dry AMD progresses, a blurred spot develops in the center of vision. With time, the spot may get bigger and darker, reducing central vision. Often, when dry AMD is limited to one eye patients do not complain of visual changes because of the ability of the other healthy eye to see clearly, allowing for driving, reading, recognizing faces and seeing fine details.

Symptoms of wet AMD may be that straight lines, such as sentences on a page, appear wavy; rapid loss of central vision; and a blurred or blind spot in the center of vision.

How is macular degeneration diagnosed?
If an ophthalmologist suspects a patient of having AMD, he or she may:

  • perform a visual acuity test to measure vision at a distance
  • perform a dilated pupil examination to see the inside of the eye with an ophthalmoscope to check for drusen (tiny yellow deposits on the retina which are the most common early signs of AMD)
  • ask the patient to look at an Amsler grid with a pattern of straight horizontal and vertical lines. To the person with AMD, the lines appear wavy, distorted or missing or a black spot may appear in the center of the grid.
  • perform a fluorescein angiography. During this test, a dye is injected into the arm and quickly travels throughout the blood system. Once the dye reaches the blood vessels in the back of the eye, photographs are taken of the eye. The dye allows the ophthalmologist to detect blood vessels that are abnormal and leaking dye.

What are the current treatment options for macular degeneration?

Currently, treatments for macular degeneration are rapidly advancing and changing approximately every three months. It is anticipated that for the next three to five years, the treatment will be changing all the time. Various treatments are currently available, but most of these treatments are directed at the early stage of wet AMD. Regardless of the treatment therapy followed, patients with advanced dry macular degeneration should check the vision in each eye, one at a time, at least once a day. By staring at the central point on an amsler grid, patients can help monitor their vision regularly and can detect distortions in vision. These distortions represent the earliest stages of wet macular degeneration.

The only costeffective worthwile treatment for wet AMD is a course of anti VEGF injections like lucentis and avastin.

Despite all these advances, we still do not have effective therapies for the vast majority of patients with dry or wet AMD. For this reason, the best option for many of our patients is to receive low vision training.

What is a macular hole?

As people age, the vitreous gel in the eye shrinks and pulls away from the retina. Usually this occurs without consequence, however, in some cases where the vitreous is attached to the macula, it can result in the formation of a macular hole. Fluid may leak under the edges of the hole, causing a microscopic retinal detachment, which results in blurring and distortion of vision.

What are the symptoms of a macular hole?

A macular hole can cause blurred or distorted vision. A hole that goes all the way through the macula can result in significant loss of central vision.

How is a macular hole diagnosed?

An ophthalmologists who suspects a macular hole may:
  • perform a visual acuity test to measure vision at a distance
  • perform a dilated pupil examination to see the inside of the eye with an ophthalmoscope
  • perform a fluorescein angiography.and or optic coherence tomography[OCT TEST]which is very accurate and non invasive

What are the treatment options for a patient with a macular hole?

Current treatment options for macular holes are limited to vitrectomy with an internal tamponade. The most commonly used procedure involves using a long-acting gas. During the surgery, the ophthalmologist will remove the vitreous gel from the eye so that it is no longer pulling on and distorting the macula. The vitreous gel is replaced with a bubble containing a mixture of air and gas or even silicone oil can be used. The long-acting gas acts as an internal, temporary bandage that holds the edge of the macular hole in place as it heals, though it prohibits the patient from traveling by air for at least six weeks. Under extenuating circumstances a shorter acting gas or the silicone can be used to possibly reduce or eliminate the prohibition of air travel.. In order to maximize the effect of the repair, the patient is usually required to remain in a face down position for one week postoperatively to allow the bubble to press against the macula and seal the hole. strict, continuous positioning enhances success rates, substantially high rates are obtained even in patients who are unable to maintain this position. The bubble will gradually be reabsorbed by the eye within a few weeks following surgery. As the bubble is reabsorbed, the vitreous cavity refills with a naturally produced fluid.

Currently, it is customary to peel the internal limiting membrane during surgery, as this may remove an impediment to healing the hole, and possibly even stimulate healing. This issue is controversial and studies of its efficacy are ongoing.

What are retinal detachments and retinal tears?

The retina lies flat against the inside, back wall of the eye. A retinal detachment occurs when the retina is lifted or pulled from its normal position. This can happen as a result of normal retraction of the vitreous which can tear the retina and allow fluid to seep beneath it causing a separation; a tumor; complications from other diseases; a severe blow to the head or eye and occasionally it is hereditary.

A retinal tear occurs when the vitreous shrinks, pulling a tear, or rip, in the retina. Most tears occur on the peripheral retina and have little effect on vision. However they may lead to an accumulation of fluid under the retina, which results in retinal detachment and significant vision loss.

What are the symptoms of retinal detachments?

Retinal detachment may be gradual or sudden, but it is usually accompanied by a dramatic loss of vision --- partial or complete. Many people see flashes of light, floaters or the appearance of a dark or gray curtain moving across the field of vision or a wavy or watery effect in their vision. These symptoms do no always mean the retina has detached, however, if they are present, an ophthalmologist should be consulted immediately as a detachment can cause permanent vision loss.

How are retinal detachments and tears diagnosed?

An ophthalmologist can diagnose retinal detachments and tears during a dilated pupil examination. Some can also be found during routine eye exams.

What is the treatment for retinal detachments and tears?

Retinal detachments are almost always repaired surgically. Treatment depends on the cause and extent of the retinal detachment. Most retinal tears are treated with cryo-therapy (use of a freezing probe) or laser therapy. Treatment usually prevents retinal detachment.

Alternatives include pneumatic retinopexy, scleral buckling procedure or vitrectomy with gas or silicone oil tamponade.

Pneumatic retinopexy involves injecting a gas bubble into the vitreous space. The bubble pushes the retinal tear against the back of the eye.

Scleral buckle is a tiny, flexible band that is placed around the outside of the eyeball to gently push the wall of the eye against the detached retina.

Vitrectomy is the surgical extraction of the vitreous humor and simultaneous replacement with a clear sterile solution or a dissolvable gas bubble.

Early treatment usually improves the vision of most patients with retinal detachment. Some will need more than one procedure to repair the damage, but some detachments cannot be repaired.

What is uveitis?

Uveitis is an inflammation of the uvea, the layer of the eye that lies between the retina and the sclera. The uvea contains many of the blood vessels which nourish the eye. Inflammation of the uvea can affect the cornea, the retina, the sclera, and other vital parts of the eye. Since the uvea borders many important parts of the eye, inflammation of this layer may be sight-threatening and more serious than the more common inflammations of the outside layers of the eye.

Uveitis has many different causes. It may develop following eye surgery or trauma. It may result from a virus (such as shingles, mumps, or herpes), a fungus (such as histoplasmosis), or a parasite (such as toxoplasmosis). In most cases, the cause remains unknown.

Uveitis can also be related to autoimmunity or come as a consequence of injury to the eye. Inflammation in one eye can result from a severe injury to the opposite eye (sympathetic uveitis).

What are the symptoms of uveitis?

Inflammation from uveitis may involve any of the following: the iris, the ciliary body or the choroid, therefore symptoms may be present in any of these structures. The symptoms include pain, blurred vision, redness, floaters or sensitivity to light.

How is uveitis diagnosed?

Uveitis is diagnosed through a routine eye examination using an ophthalmoscope.

What is the treatment for uveitis?

Uveitis may be treated with eyedrops, injections or oral medication. The most severe cases may require chemotherapy to suppress the immune system.

What is CMV retinitis?

Cytomegalovirus infection of the retina, known as CMV retinitis, occurs primarily in patients with acquired immunodeficiency syndrome, AIDS, though it can occur in patients with other immunosuppressive diseases. This serious infection is found in 20 - 30% of people with AIDS. Most CMV infections occur in people whose T-cell counts is dangerously low, usually under 40.

What are the symptoms of CMV retinitis?

People with CMV retinitis generally do not experience any pain but may develop floating spots in their vision, flashing lights, blind spots, blurred vision or loss of central or peripheral vision. CMV can also cause the retina to separate from the back of the eye. The disease generally starts in one eye, but often will involve both eyes. If untreated the disease can bring about retinal detachment and cause blindness in as little as two to six months.

How is CMV retinitis diagnosed?

Occasionally, the condition is detected during a routine exam when the infectious process is early and located in the peripheral retina.

What is the treatment for CMV retinitis?

Patients diagnosed with CMV retinitis are generally treated with antiviral medications, gancyclovir, foscarnet or cidofovir which can slow the progression of the disease but cannot cure it. The medications are administered intravenously, in pill form or via pellet implanted directly into the vitreous in the eye. The pill and intravenous medications allow for immediate infusion while the pellet allows for a slow, timed release of the medicine for approximately 5 to 8 months.

Nearly 100% of patients will eventually have a relapse of CMV retinitis, despite the best attempts at control.

What is retinopathy of prematurity?

Retinopathy of prematurity (ROP) is the leading cause of childhood blindness in developed countries..

Premature or low birth weight babies often need to receive oxygen until their immature lungs develop. Today, physicians know that exposure to high levels of oxygen over extended periods of time can trigger the disease in infants, causing the retina's tiny developing blood vessels to grow wildly and produce scars. In some children, the retina is able to recover and damage is moderate. However, in severe cases, there is retinal detachment and, ultimately, blindness.

What is the current treatment for retinopathy of prematurity?

In a multi-center, collaborative four-year study, physicians identified the level of oxygen dangerous to an infant's eyes. More importantly, the study revealed that a baby's exposure to oxygen in the first week after birth is less critical than exposure in the weeks that follow. In other words, low-birth-weight babies who remain on oxygen during the second through the fourth week are at greater risk of developing ROP and of developing its most severe form.

It is anticipated that the results of this study will generate new technology that more accurately monitors and controls the amount of oxygen that a baby's body absorbs while on life support. Because life support is often critical in preventing brain damage and death, the need for a solution, as soon as possible, is clear.

What is retinoblastoma?

Retinoblastoma (RB) is a rare form of cancer affecting the light-sensitive retinal cells that enable sight. Although the disease is very rare, it is the most common ocular malignancy in children and the third most common cancer to affect children --- occurring in one out of every 15,000 births. In the United States, 250 to 350 new cases are diagnosed each year --- 90 percent of which occur in children under five years of age.

There are two types; one is hereditary and affects both eyes (occurs in 10% of cases) and the other type is non-hereditary and affects only one eye, carrying no increased risk of a second tumor. Although the cancer is genetically determined, only 6 percent of newly diagnosed RB patients are found to have a positive family history of the disease. Forty percent of all children have a lifelong cancer risk from abnormality in the RB gene located in chromosome 13. In all cases, genetic counseling is important for children with a germ-line mutation.

What are the current treatment options for retinoblastoma?

Early detection of RB greatly enhances the possibility of a cure and the preservation of the greatest amount of vision, though it can lead to vision loss of one or both eyes. The treatment of RB depends on the size and location of the tumor and whether one or both eyes are involved. With earlier detection and improved treatments, the prognosis for vision and life for RB patients has improved significantly in the past twenty years. However, because the disease is so rare, many pediatricians and primary care providers may not recognize the early signs, and parents rarely notice the subtle changes that may identify a tumor in their child's eyes. Left untreated, RB tumor nodules grow rapidly, expanding to fill the eye and extending along the optic nerve to the brain, ultimately causing death.

What is retinitis pigmentosa?

Retinitis pigmentosa (RP) is a group of diseases which tend to run in families that cause progressive degeneration of the retina in both eyes. It progresses from night blindness to loss of the peripheral visual field. The signs of the disease usually present in youth or young adulthood, but can occur at any age. Over many years, RP then progresses to tunnel vision and finally blindness.

What are the symptoms of retinitis pigmentosa?

The symptoms of RP vary and can include night blindness in early stages of the disease. Night blindness refers to an inability to adjust vision to the darkness or a very slow adjustment. During later stages, the next symptom to appear is a gradual loss of peripheral or side vision so that the person can only see through a small area of the eye and only straight ahead, this is also referred to as tunnel vision.

What are the current treatment options for retinitis pigmentosa?

Unfortunately, there is currently no effective treatment leading to a cure for retinitis pigmentosa. Occasionally, some treatments can slow the degeneration of vision or preserve vision for a longer period of time, these include vitamin therapies. Many patients with progressive RP may continue to perform daily living tasks with the use of low vision aids, telescopic lenses to improve distance vision, magnifying lenses, field enhancers and others. patients’ remaining vision, prescribe appropriate low vision aids and train patients in their proper use for maximum benefit.

What are flashes and floaters?

Flashes are a brief perception of light in the field of vision and floaters are bits of optical debris usually in the vitreous that are interpreted as threats or small spots or circles.

As a person ages, the vitreous thins and may separate from the retina, causing a posterior vitreous detachment, a common, typically harmless condition. When posterior vitreous detachment occurs, the detached vitreous can pull on the retina accompanied by flashes of light or tiny bits of vitreous that cast shadows on the retina creating floaters.

What are the symptoms of floaters and flashes?

Floaters can appear to be black spots or small circles, cob webs that may move or remain in one place. Flashes take on the appearance of bright flashes of light. More serious symptoms includes a sudden decrease of vision accompanied by floaters and flashes; a curtain that obstructs the field of vision; or a sudden increase in floaters.

How are floaters and flashes diagnosed?

Your ophthalmologist will exam your retina through dilated pupils with an ophthalmoscope.

What are the current treatment options for floaters and flashes?

In most cases of posterior vitreous detachment, surgery is not recommended and the patient can learn to ignore the floaters and they usually become less bothersome over several weeks. In more severe cases, vitrectomy may be considered only if vision is significantly compromised.