What is Uveitis?

What is Uveitis?

Uveitis is a general term describing a group of inflammatory diseases that produces swelling and destroys eye tissues. These diseases can slightly reduce vision or lead to severe vision loss.
The term "Uveitis" is used because the diseases often affect a part of the eye called the uvea. Nevertheless, Uveitis is not limited to the uvea. These diseases also affect the lens, retina, optic nerve, and vitreous, producing reduced vision or blindness.
Uveitis may be caused by problems or diseases occurring in the eye or it can be part of an inflammatory disease affecting other parts of the body.
It can happen at all ages and primarily affects people between 20 – 60 years old.
Uveitis can last for a short (acute) or a long (chronic) time. The severest forms of Uveitis reoccur many times.
Eye care professionals may describe the disease more specifically as:
Anterior Uveitis
Intermediate Uveitis
Posterior Uveitis
PanUveitis Uveitis
Eye care professionals may also describe the disease as infectious or noninfectious Uveitis.

What is the Uvea and What Parts of the Eye are Most Affected by Uveitis?

The uvea is the middle layer of the eye which contains much of the eye's blood vessels (see diagram). This is one way that inflammatory cells can enter the eye. Located between the sclera, the eye's white outer coat, and the inner layer of the eye, called the retina, the uvea consists of the iris, ciliary body, and choroid:
Iris: The colored circle at the front of the eye. It defines eye color, secretes nutrients to keep the lens healthy, and controls the amount of light that enters the eye by adjusting the size of the pupil.
Ciliary Body: It is located between the iris and the choroid. It helps the eye focus by controlling the shape of the lens and it provides nutrients to keep the lens healthy.
Choroid: A thin, spongy network of blood vessels, which primarily provides nutrients to the retina.
Uveitis disrupts vision by primarily causing problems with the lens, retina, optic nerve, and vitreous (see diagram):

Lens: Transparent tissue that allows light into the eye.
Retina: The layer of cells on the back, inside part of the eye that converts light into electrical signals sent to the brain.
Optic Nerve: A bundle of nerve fibers that transmits electrical signals from the retina to the brain.
Vitreous: The fluid filled space inside the eye.

Causes and Risk Factors

What Causes Uveitis?

Uveitis is caused by inflammatory responses inside the eye.
Inflammation is the body's natural response to tissue damage, germs, or toxins. It produces swelling, redness, heat, and destroys tissues as certain white blood cells rush to the affected part of the body to contain or eliminate the insult.
Uveitis may be caused by:

• An attack from the body's own immune system (autoimmunity).
• Infections or tumors occurring within the eye or in other parts of the body.
• Bruises to the eye.
• Toxins that may penetrate the eye.

The disease will cause symptoms, such as decreased vision, pain, light sensitivity, and increased floaters. In many cases the cause is unknown.
Uveitis is usually classified by where it occurs in the eye.

Article republished from: http://www.nei.nih.gov/health/uveitis/uveitis.asp

Vitreous Detachment

What is vitreous detachment?

Most of the eye's interior is filled with vitreous, a gel-like substance that helps the eye maintain a round shape. There are millions of fine fibers intertwined within the vitreous that are attached to the surface of the retina, the eye's light-sensitive tissue. As we age, the vitreous slowly shrinks, and these fine fibers pull on the retinal surface. Usually the fibers break, allowing the vitreous to separate and shrink from the retina. This is avitreous detachment.
In most cases, a vitreous detachment, also known as a posterior vitreous detachment, is not sight-threatening and requires no treatment.

Risk Factors

Who is at risk for vitreous detachment?

A vitreous detachment is a common condition that usually affects people over age 50, and is very common after age 80. People who are nearsighted are also at increased risk. Those who have a vitreous detachment in one eye are likely to have one in the other, although it may not happen until years later.

Symptoms and Detection

What are the symptoms of vitreous detachment?

As the vitreous shrinks, it becomes somewhat stringy, and the strands can cast tiny shadows on the retina that you may notice as floaters, which appear as little "cobwebs" or specks that seem to float about in your field of vision. If you try to look at these shadows they appear to quickly dart out of the way.
One symptom of a vitreous detachment is a small but sudden increase in the number of new floaters. This increase in floaters may be accompanied by flashes of light (lightning streaks) in your peripheral, or side, vision. In most cases, either you will not notice a vitreous detachment, or you will find it merely annoying because of the increase in floaters.

How is vitreous detachment detected?

The only way to diagnose the cause of the problem is by a comprehensive dilated eye examination. If the vitreous detachment has led to a macular hole or detached retina, early treatment can help prevent loss of vision.

Treatment

How does vitreous detachment affect vision?

Although a vitreous detachment does not threaten sight, once in a while some of the vitreous fibers pull so hard on the retina that they create amacular hole to or lead to a retinal detachment. Both of these conditions are sight-threatening and should be treated immediately.
If left untreated, a macular hole or detached retina can lead to permanent vision loss in the affected eye. Those who experience a sudden increase in floaters or an increase in flashes of light in peripheral vision should have an eye care professional examine their eyes as soon as possible.
Article republished from http://www.nei.nih.gov/health/vitreous/vitreous.asp#a

Who is likely to develop Dry Eye?

Who is likely to develop Dry Eye?

Elderly people frequently experience dryness of the eyes, but Dry Eye can occur at any age. Nearly five million Americans 50 years of age and older are estimated to have Dry Eye. Of these, more than three million are women and more than one and a half million are men. Tens of millions more have less severe symptoms. Dry Eye is more common after menopause. Women who experience menopause prematurely are more likely to have eye surface damage from Dry Eye.

Treatment

How is Dry Eye treated?

Depending on the causes of Dry Eye, your doctor may use various approaches to relieve the symptoms.

Dry Eye can be managed as an ongoing condition. The first priority is to determine if a disease is the underlying cause of the Dry Eye (such as Sjögren's syndrome or lacrimal and meibomian gland dysfunction). If it is, then the underlying disease needs to be treated.

Cyclosporine, an anti-inflammatory medication, is the only prescription drug available to treat Dry Eye. It decreases corneal damage, increases basic tear production, and reduces symptoms of Dry Eye. It may take three to six months of twice-a-day dosages for the medication to work. In some cases of severe Dry Eye, short term use of corticosteroid eye drops that decrease inflammation is required.

If Dry Eye results from taking a medication, your doctor may recommend switching to a medication that does not cause the Dry Eye side effect.

If contact lens wear is the problem, your eye care practitioner may recommend another type of lens or reducing the number of hours you wear your lenses. In the case of severe Dry Eye, your eye care professional may advise you not to wear contact lenses at all.

Another option is to plug the drainage holes, small circular openings at the inner corners of the eyelids where tears drain from the eye into the nose. Lacrimal plugs, also called punctal plugs, can be inserted painlessly by an eye care professional. The patient usually does not feel them. These plugs are made of silicone or collagen, are reversible, and are a temporary measure. In severe cases, permanent plugs may be considered.

In some cases, a simple surgery, called punctal cautery, is recommended to permanently close the drainage holes. The procedure helps keep the limited volume of tears on the eye for a longer period of time.

In some patients with Dry Eye, supplements or dietary sources (such as tuna fish) of omega-3 fatty acids (especially DHA and EPA) may decrease symptoms of irritation. The use and dosage of nutritional supplements and vitamins should be discussed with your primary medical doctor.

What can I do to help myself?

• Use artificial tears, gels, gel inserts, and ointments - available over the counter - as the first line of therapy. They offer temporary relief and provide an important replacement of naturally produced tears in patients with aqueous tear deficiency. Avoid artificial tears with preservatives if you need to apply them more than four times a day or preparations with chemicals that cause blood vessels to constrict.
• Wearing glasses or sunglasses that fit close to the face (wrap around shades) or that have side shields can help slow tear evaporation from the eye surfaces. Indoors, an air cleaner to filter dust and other particles helps prevent Dry Eyes. A humidifier also may help by adding moisture to the air.
• Avoid dry conditions and allow your eyes to rest when performing activities that require you to use your eyes for long periods of time. Instill lubricating eye drops while performing these tasks.

Article republished from: http://www.nei.nih.gov/health/dryeye/dryeye.asp

Conjunctivitis: Do antibiotics help?

In more than half of all people who have conjunctivitis, the infection goes away without treatment within a week. Antibiotic eye drops or ointment can speed up recovery. Adverse effects are very rare.

Conjunctivitis makes people’s eyes red and inflamed. It often affects both eyes because the infection can easily spread from one eye to the other. Your eyes get watery and produce a yellowish-white discharge that makes your eyelids stick together. They may become very sore too. Conjunctivitis is contagious but often gets better within a week, even without any treatment. So it is often enough to simply wait.

Conjunctivitis is usually caused by bacteria or viruses.  Because conjunctivitis usually goes away so quickly, though, it is generally not worth doing tests to find out if it is a bacterial or viral infection. Doctors often prescribe antibiotics just in case, in the form of eye drops or ointments. Antibiotics only work against bacteria, though, and not against viruses, so they are not always effective.

Some people use non-antibiotic eye drops. The use of cold or warm compresses is common too. But there is not enough research on these approaches to be able to say whether they have a benefit, no effect, or are possibly even harmful. Sometimes conjunctivitis is linked to an allergy. Then it is treated with allergy medicines like antihistamines.

Research on antibiotics in the treatment of conjunctivitis

Two groups of researchers from the Cochrane Collaboration (an international network of researchers) and from various universities in England, the Netherlands and Australia analyzed the results of trials on the treatment of conjunctivitis with antibiotics. They wanted to find out whether antibiotics help in the treatment of ordinary conjunctivitis, as well as which possible disadvantages they have.

The researchers only analyzed the results of studies that compared at least two groups of people. One group of people used antibiotic eye drops or ointments. The other group used non-antibiotic eye drops or ointments, or did not have any treatment at first. The researchers were only interested in studies in which the participants were randomly assigned to one of the treatment groups. This kind of study, called a randomized controlled trial, delivers the most reliable results. Read our information "Evidence-based medicine" to find out more about how good-quality trials are carried out.

The researchers found 12 trials, involving a total of about 4,000 people with conjunctivitis. Both children and adults participated in the trials.

Antibiotics can speed up recovery

Overall, the analysis of the trial results showed that conjunctivitis goes away somewhat faster if antibiotics are used. This is what was found for people who went to see their family doctor because they had conjunctivitis:

• The infection cleared up within one week in 71 out of 100 people who did not use antibiotics.

• The infection cleared up within that same amount of time in 80 out of 100 people who used antibiotics.

In other words, antibiotics were found to speed up recovery in 9 out of 100 people.

In studies that were carried out in a specialist practice, it took a little longer for the infection to clear up – both in the people who used antibiotics and in those who did not use antibiotics. One possible explanation for this is that people who go to see a specialist doctor probably have more severe cases of conjunctivitis. But the antibiotics had a similar beneficial effect to that found in the family doctor trials.

None of the trials reported that antibiotics had adverse effects. The trials did not look into whether antibiotics helped lower the risk of the infection spreading.

Recognizing signs of complications and avoiding the spread of infection

As already mentioned, conjunctivitis usually goes away without treatment. But some symptoms could be signs of more serious problems. These symptoms include worsening vision, increased sensitivity to light, the feeling that you have something in your eye, and a severe headache together with nausea. It is important to see a doctor if you have any of these symptoms.

In people who wear contact lenses, the infection can spread to the cornea (the clear surface of the eye itself). Inflammation of the cornea, also known as keratitis, is not common though: it is estimated that conjunctivitis leads to keratitis in about 3 out of every 10,000 contact lens wearers. In the trials that the researchers included in their analysis, none of the participants developed keratitis.

If conjunctivitis is caused by viruses it can be highly contagious and hard to get rid of. But there are several things that can be done to try to stop viral infections from spreading. Because the virus is easily spread through finger contact, it is important to avoid touching your eyes with your hands, and to wash your hands if you do accidentally touch your eyes. It is also a good idea to have your own towels and washcloths, and not to share them with other people. Another important way to protect others from infection is by not shaking hands with them and not touching their face.

 

Original Article found at http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0005040/

Published by the Institute for Quality and Efficiency in Health Care (IQWiG)Next planned update:
October 2015. You can find out more about how our health information is updated in our text "Informed Health Online: How our information is produced".

References

• IQWiG health information is based on research in the international literature. We identify the most scientifically reliable knowledge currently available, particularly what are known as “systematic reviews”. These summarize and analyze the results of scientific research on the benefits and harms of treatments and other health care interventions. This helps medical professionals and people who are affected by the medical condition to weigh up the pros and cons. You can read more about systematic reviews and why these can provide the most trustworthy evidence about the state of knowledge in our information "Evidence-based medicine". We also have our health information reviewed to ensure medical and scientific accuracy.
• Jefferis J, Perera R, Everitt H, van Weert H, Rietveld R, Glasziou P et al. Acute infective conjunctivitis in primary care: who needs antibiotics? An individual patient data meta-analysis. Br J Gen Pract 2011; 61(590): e542-548. [Full text]
• Sheikh A, Hurwitz B, van Schayck CP, McLean S, Nurmatov U. Antibiotics versus placebo for acute bacterial conjunctivitis. Cochrane Database Syst Rev 2012; (9): CD001211. [Summary]

 

What is a Cataract?

Cataract Defined

What is a Cataract?

A Cataract is a clouding of the lens in the eye that affects vision. Most Cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have a Cataract or have had Cataract surgery.

A Cataract can occur in either or both eyes. It cannot spread from one eye to the other.

What is the lens?

The lens is a clear part of the eye that helps to focus light, or an image, on the retina. The retina is the light-sensitive tissue at the back of the eye.

In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain.

The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a Cataract, the image you see will be blurred.

Are there other types of Cataract?

Yes. Although most Cataracts are related to aging, there are other types of Cataract:

1. Secondary Cataract. Cataracts can form after surgery for other eye problems, such as glaucoma. Cataracts also can develop in people who have other health problems, such as diabetes. Cataracts are sometimes linked to steroid use.
2. Traumatic Cataract. Cataracts can develop after an eye injury, sometimes years later.
3. Congenital Cataract. Some babies are born with Cataracts or develop them in childhood, often in both eyes. These Cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed.
4. Radiation Cataract. Cataracts can develop after exposure to some types of radiation.

Normal vision

The same scene as viewed by a person with Cataract

What Is Orthokeratology?

What Is Orthokeratology?

In the most basic of terms Accelerated Overnight Orthokeratology or Ortho-k is the science of changing the curvature or shape of the cornea to change how light is focused on the retina at the back of one's eye.

Think of the cornea as the eye's equivalent of a watch crystal. It is a clear, dome shaped structure that overlies the colored iris. Its tissue is most similar to clear, wet skin; and like skin it is very pliable. Because the cornea separates the eye from air and the rest of the outside world and because it has a curvature that bends light towards the back of the eye, it is responsible for most of the eye's corrective power and contributes to various conditions such as nearsightedness (myopia), farsightedness (hyperopia), and the blur of astigmatism.

When you choose Ortho-k a few key tests must be performed. Chief among these tests is the determination that your eyes are healthy. The Orthokeratologist will examine the retina and also the health of the outside of the eye. The other key procedure is the mapping of your cornea. To do this an instrument called a Topographer is used. Just like a topographical map of a camping area show hills, plains, and valleys; the topography of the eye shows your doctor exactly how your cornea is shaped. The information from your corneal mapping plus the size of your cornea and the prescription needed to correct your vision are all used to design the retainer lenses (corneal molds) needed to create the Ortho-k effect.

On the day you pick up your Ortho-k retainer lenses you will be instructed in how to insert, remove, and take care your vision retainers. The fit of your retainers will be evaluated and you will be scheduled to be seen after your first night of wear. On day 1, your doctor will re-evaluate your fit and newly corrected vision and another mapping of your cornea will be performed.

Throughout your initial fitting period, your Orthokeratologist will monitor your corneal health and the effectiveness of treatment. At certain times your retainer lens fit may be modified to achieve your goals.

Orthokeratology can produce results in a surprisingly short period of time. The length of treatment to achieve your goals can vary from patient to patient. Factors which can affect the speed of treatment include:

1. your initial prescription
2. corneal rigidity
3. tear quality and quantity
4. your expectations.

We advise patients that they may need to use their retainers every night to maintain their newly corrected vision although some patients are able to vary their wearing time to once every two to four nights. The reason for this is due to the flexibility of your cornea.