Endophthalmitis

What is Endophthalmitis?

Endophthalmitis is a term for when the inner layers of your eye become inflamed. This typically happens when an infection, caused by bacteria or other germs, spreads inside your eye, leading to condition called infection-induced inflammation. The fluids inside your eye (namely, the vitreous and aqueous fluids) also show signs of the infection.

Endophthalmitis can happen in two ways: ‘exogenous’, which means the germs entered your eye from the outside, and ‘endogenous’, which means the germs came from inside your body. If it’s the ‘exogenous’ type, it could be due to injury to your eye (post-traumatic) or following an eye surgery (post-operative).

The type of endophthalmitis you have, whether it’s post-operational, post-traumatic or endogenous, influences how the symptoms present, what kind of germs are causing it, and what the outcome for your vision might be.

It’s important to know that endophthalmitis is considered a serious eye emergency. If you think you’re experiencing symptoms, make sure to get medical help right away. If caught and treated early, it can prevent severe loss of vision or other damage to your eye.

What Causes Endophthalmitis?

Endophthalmitis is an eye infection that can be caused by bacteria or fungi. A recent study found that 85.1% of these infections are from positive bacteria, 10.3% from negative bacteria, and 4.6% from fungi. Common bacteria causing this condition are Staphylococcus epidermidis, other Staphylococcus types, Streptococcus viridans, Staphylococcus aureus, Enterobacteriaceae, and Pseudomonas aeruginosa.

What type of bacteria or fungus is causing the infection often depends on factors like the source (such as plant matter or a foreign object in the eye), how the infection spread (after surgery, from an injury, or slowly over time), where the patient is located, and the patient’s personal characteristics.

For example, in cases where the infection follows an injury, Staphylococci and Bacillus cereus are often found. If the eye infection develops soon after surgery (within six weeks), it’s typically due to bacteria that usually live harmlessly around the eye (like Staphylococcal epidermidis) getting into the inner part of the eye during the operation.

On the other hand, if the infection takes longer to develop after cataract surgery (longer than six weeks), it can be recognized by symptoms like an inflammatory reaction in the eye, vitritis (an inflammatory condition affecting the jelly-like part of the eye), and cystoid macular edema (a condition that causes fluid build-up and swelling in the retina). This type of infection is often caused by bacteria, most commonly Propionibacterium acnes and Coagulase-negative Staphylococcus, although fungal infections can occur as well.

There are instances where endophthalmitis can develop without any holes or tears in the outer part of the eye. Such conditions include after scleral buckling, a surgical procedure to treat certain eye conditions, from infections caused by wearing contact lenses, or after LASIK surgery.

Infections that originate from outside the eye (‘exogenous endophthalmitis’) are most often caused by different species of bacteria. Fungi can also cause these infections, although this is less common. Alternatively, when the infections start from inside the body (‘endogenous endophthalmitis’), they are most often caused by fungi, especially a type called Candida. Among bacteria, staphylococcal species are the main cause in the western populations, while for East Asian populations, Klebsiella pneumoniae is typically the cause.

In general, endophthalmitis, an infection of the inner eye, can be caused by various bacteria and fungi. The specific cause and progression of the infection can vary depending on various factors such as the source of the infection, the patient’s location, and the patient’s personal characteristics.

Risk Factors and Frequency for Endophthalmitis

The frequency of different types of endophthalmitis, an inflammation inside the eye, vary based on the specific location, the level of expertise at the eye care center, and length of the study. It’s important to note that studies conducted before 2005 have few cases of endophthalmitis following an injection of anti-VEGF (a medication used to slow down vision loss) into the eyeball. This is because anti-VEGF treatments were only approved by the FDA in 2004.

A recent U.S. study revealed that endophthalmitis occurred in 0.04% of patients after cataract surgery and in 0.016% of patients after an eyeball injection. The occurrence of endophthalmitis as a result of traumatic injury ranged from 0.9% to 17%.

Studies in Asia reported an incidence of 0.023% to 0.076% of endophthalmitis after cataract surgery, and 0.01% to 0.10% following eyeball injections.

Regarding different types of surgery inside the eye, the implantation of secondary intraocular lenses seems to carry a relatively high risk (0.36%) for acute endophthalmitis. Trabeculectomy, a procedure used to treat glaucoma, also appears to have a high risk (1.8%, or even up to 5.7%, in some instances) for delayed or late onset endophthalmitis, particularly after the use of certain medications.

• Endophthalmitis had the lowest rates (0.046%) following surgeries like pars plana vitrectomy compared to other eye surgeries.
• There were no significant differences in endophthalmitis rates following an injection of different anti-VEGF medications.
• Instances of endophthalmitis did occur after the use of a particular medication due to issues like a break in cold chain procedure, inadequate compounding of medication or use of counterfeit drugs.

Signs and Symptoms of Endophthalmitis

Endophthalmitis is an inflammation inside the eye. It can occur after surgery, injury, or due to an infection spreading from another part of the body. The amount of vision lost and eye pain experienced varies and some people may have other symptoms like a swollen eyelid, red eye, sensitivity to light, discharge from the eye, and seeing floaters. There are several types of this condition:

• Postoperative endophthalmitis: Common signs generally include blurred vision, swelling in the cornea, pus in the eye, severe inflammation inside the eye, and difficulty in seeing the back of the eye.
• Chronic endophthalmitis: This type usually causes slow and subtle inflammation in the front part of the eye and the vitreous. Here, good vision may persist until late stages.
• Endogenous endophthalmitis: This condition can affect both eyes and is usually accompanied by signs of general illness like high body temperature, and upset stomach. The symptoms include eye pain, blurry vision, and redness. In severe cases, a pus-filled abscess might be seen inside the eye. In some cases, this variant begins as a specific type of inflammation in the layer of blood vessels in the eye, which then expands into the jelly-like substance (vitreous) filling the eye cavity.
• Endophthalmitis after infectious keratitis: In this type, pus accumulates in the eye and the individual may experience severe vision loss. An ultrasound of the back of the eye can confirm a diagnosis in these cases.

If endophthalmitis worsens without effective treatment, it can lead to complete inflammation of all layers of the eye, weakening and bursting of the cornea, and shrinkage of the eyeball. Because this condition can seriously harm the structures of the eye, quick diagnosis and treatment are essential.

Some key info doctors consider while diagnosing include:

• What was the triggering event (like surgery, trauma or infection from another part of the body)?
• When did the symptoms appear – suddenly or over time?
• How fast has the condition progressed – did it become worse quickly or gradually?
• Are there any long-term illnesses that may affect treatment or suggest infection sources?

As part of the examination, doctors may want to do a few things:

• Check your vision, including how accurately you’re seeing things.
• Examine areas around your eye for other infections.
• Check the movements of your eyes.
• Inspect the front part of your eye, especially any places which might be letting bacteria in.
• Measure pressure inside your eye.
• Examine the back of your eye for inflammation if your eye is clear enough to allow this.

In these exams, there are some standards used to assess the level of inflammation inside the eye:

• Grade 1: You can see more than half of your visual field
• Grade 2: Only blood vessels in the middle layer of the eye are visible.
• Grade 3: Some blood vessels are seen, but no blood vessels in the middle layer of the eye are.
• Grade 4: No blood vessels are seen but there is still a red reflection in the eye.
• Grade 5: No red reflection is seen in the eye.

Testing for Endophthalmitis

In plain language, this text talks about different types of tests used to diagnose a condition that affects the eyes called endophthalmitis. There are several procedures that doctors use to gather the information they need. Let’s go through them:

Firstly, doctors use a range of imaging techniques:

1. Slit-lamp photography, which is a way to take pictures of the front of your eye.
2. Fundus photographs: this is a special type of photography, often involving an Optos device, which uses lasers to take detailed pictures of the back of your eye, even if your pupil is small or there’s some cloudiness in your eye.
3. Fundus Fluorescein Angiogram (FFA): This is a type of test involving dye to show up blood vessels at the back of your eye. It helps to rule out other diseases.
4. Optical coherence tomography (OCT) provides the doctor with even more details about the retina, the choroid (the layer beneath the retina), and blood vessels when the back of your eye is visible.
5. Anterior segment OCT is used if there might be an infection affecting the front part of your eye from conditions like a severe form of eye infection called keratitis.

Another common imaging test is an Ultrasound B-scan. This test can identify inflammation in the jelly-like substance filling the eye, the vitreous, and can also show other changes in the eye anatomy and structures. This method can help in following up vitreous inflammation over time after intravitreal injections, a treatment given directly into your eyes.

Aside from imaging, there are also different ways to obtain samples from your eye, to help identify the cause of illness:

1. The doctor may collect a sample from the watery part of your eye (the anterior chamber) using a very thin needle. This is called an anterior chamber tap. The needle collects a small amount of fluid, which can be tested for causes of infection.
2. The doctor might also perform a vitreous tap/biopsy, where a small sample of the jelly-like substance inside the eye is collected with a needle. Although there is a slight risk of causing the retina to peel away from the back of the eye (retinal detachment), the value of this type of sample is that it usually provides more accurate test results than fluid from the front of the eye.

All of these samples are then sent off to the lab so they can figure out exactly what is causing the problem. Sometimes, these lab tests might involve a technique called PCR (“polymerase chain reaction”), which can identify even tiny amounts of bacteria or other pathogens. However, there might be issues with this technique such as high costs and risk of contamination, so it’s not always used.

Besides these eye-specific tests, your doctor will also carry out a general health check. This might include finding out whether you have a fever or checking for an elevated ESR, which is a test that can indicate inflammation in your body. A blood test can be carried out to check your overall health and to make sure that any medication you’ve been given isn’t causing harm to your organs. Finally, if the endophthalmitis might have come from somewhere else in your body, your doctors will try to locate where the original infection might be.

Treatment Options for Endophthalmitis

Endophthalmitis is a severe eye emergency that requires immediate treatment. The main goals of treating endophthalmitis are to get rid of or control the infection, manage inflammation, and provide supportive care.

1. Getting Rid of or Controlling the Infection

There are several ways to control or eliminate the infection caused by endophthalmitis.

A. Systemic Antibiotics: These are drugs delivered to the whole body usually through the mouth or injection. Some antibiotics can achieve therapeutic levels in the eye’s vitreous, or the clear gel that fills the space between the lens and retina in your eye. However, the use of systemic antibiotics in treating endophthalmitis is a matter of debate.

B. Local Antibiotics: These are drugs that are applied directly to the eye. A combination of two drugs, one focused on treating Gram-positive bacteria and the other on Gram-negative bacteria, is typically used initially. As soon as we know which bacteria are causing the infection, more specific treatment is chosen.

C. Intravitreal Injections: These are injections that are given directly into the eye to treat the infection where it is occurring. The benefit of these injections is that it allows high drug levels to be put directly into the eye’s vitreous cavity, which can help avoid side effects from systemic drugs. Usually, two broad-spectrum antibiotics are chosen initially.

D. Vitrectomy: This is a surgical procedure where the vitreous gel is removed from the inside of the eye. It aids in oxygenating the retina, decreasing inflammation, reducing the infection load, and speeding visual recovery.

2. Managing Inflammation

Corticosteroids, which are strong anti-inflammatory medications, are the primary agents used in handling inflammation in endophthalmitis. However, they may not be used if the endophthalmitis is caused by a fungal infection as they can promote fungal growth.

3. Supportive Therapy

This includes using drugs to paralyze the muscles controlling the eye’s lens (cycloplegic agents), help lower high eye pressure, and treat severe corneal edema (swelling of the clear front layer of the eye).

Prevention

While endophthalmitis cannot be completely prevented, different measures can significantly reduce its incidence. These measures include proper eye cleaning before surgery, checking for preexisting eye infections, ensuring the nasolacrimal (tear) duct is not blocked, promptly repairing any damage to the conjunctiva (the clear layer covering the front portion of the eye), and using certain antibiotics during eye surgery. However, using intracameral (injected into the eye’s camera-like front chamber) antibiotics should be done cautiously due to reports of associated eye damage.

Furthermore, following a strict policy of not talking and wearing masks during the procedure has been seen to be effective in reducing post-injection endophthalmitis.+

Lastly, immediate surgical repair of open globe injuries and preventive intravitreal injection of antibiotics can help reduce rates of post-traumatic endophthalmitis.

What else can Endophthalmitis be?

Conditions that are confused with endophthalmitis, an inflammation of the inner eye, can be divided into two categories, ones that occur after surgery and ones that do not.

The conditions that can be confused with endophthalmitis after surgery include:

• Toxic Anterior Segment Syndrome (TASS), which is an intense inflammation of the front part of the eye that happens within 24 hours of surgery
• A scenario where the lens matter is dislocated towards the back of the eye
• An intense reaction after a vitrectomy, which is a surgical procedure to remove the vitreous humor in the eye
• A severe immune reaction to the eye’s natural crystalline lens (Phacoanaphylaxis)

Non-surgical conditions that might be mistaken for endophthalmitis are:

• Chronic uveitis, which can resemble long-lasting endophthalmitis
• A foreign body left inside the eye
• An old vitreous hemorrhage i.e., a bleed into the jellylike part of the eye
• Retinal inflammation due to a parasite called Toxoplasma (Toxoplasma retinochoroiditis)
• Necrotic retinoblastoma, a condition in which cancer cells cause death of the retinal tissue
• Acute retinal necrosis, an inflammation of the retina that can rapidly cause vision loss
• Severe panuveitis, a inflammation that affects all three layers of the uvea
• Seasonal hyperacute panuveitis (SHAPU), a mysterious eye disease seen mostly in girls, peaking in certain seasons
• Inflammation in the eye due to a parasitic cyst (Intravitreal cysticercus)

What to expect with Endophthalmitis

The vision recovery of a patient suffering from endophthalmitis, which is an inflammation of the inner eye, is dependent on a range of factors. These include:

The type of endophthalmitis: Visual recovery tends to be better in patients suffering from post-surgical endophthalmitis where no infection-causing bacteria or fungi can be identified. However, endophthalmitis that occurs due to a drainage implant for glaucoma (known as “bleb-associated”) or as a result of bacterial and fungal infections originating within the body (“endogenous”), typically has a worse impact on vision.

The infecting organism: Endophthalmitis caused by certain types of bacteria, such as Streptococcus, Bacillus, Pseudomonas, and a type of fungus called Candida, often lead to poor vision outcomes.

Initial vision condition: In a particular study known as the EVS study, it was found that a patient’s visual acuity, or clarity of vision, at the time of presenting the condition was a strong predictor of their vision outcome and response to a specific surgical procedure known as a vitrectomy.

Treatment timing: The quicker a proper treatment is started for post-traumatic endophthalmitis, especially when caused by Bacillus species, the better the chances are for a positive vision outcome. According to the EVS study, an early vitrectomy increased the chances of achieving vision scores of 20/40 and 20/100 and was less likely to worsen to <5/200 in patients who could only see light before the surgery.

The patient’s overall health: Patients with a compromised immune system and those with endogenous endophthalmitis are prone to multiple infections simultaneously, which can worsen their final outcome.

In the EVS study on endophthalmitis following cataract surgery, it was found that only 53% of treated eyes had a final visual clarity of 20/40 or better, and 15% had a vision score of 20/200 or worse.

If endophthalmitis is left untreated or not adequately treated, it can progress to panophthalmitis, a more severe inflammation of the eye, which may require removal of the eyeball. Those at a higher risk for needing this procedure include patients with a corneal ulcer, endogenous endophthalmitis, and poor initial vision quality.

Possible Complications When Diagnosed with Endophthalmitis

Common Side Effects:

• Panophthalmitis
• Glaucoma
• Orbital cellulitis
• Spreading of the infection to the brain
• Bloodstream infections (Septicemia)
• Loss of vision
• Phthisis – a condition where your eye becomes shrunken and darkened
• Hypotony – abnormally low pressure in the eye
• Painful blind eye

Preventing Endophthalmitis

After having any kind of surgery inside the eye, it’s crucial that patients are aware of the signs of endophthalmitis. These warning signs can include things such as eye pain, an unusual redness in the eye, and blurry vision. Being released from the hospital doesn’t mean you should ignore these symptoms. Spotting this condition early and getting quick treatment is essential. Patients should understand how serious this condition can be and the fact that drug therapy, often intensive, is required.