Corneal inflammation of the eyes (keratitis)

Inflammation of the cornea - keratitis

Corneal inflammation (keratitis) is known as inflammation of the cornea (cornea) in the eye and possibly also of adjacent structures, such as the conjunctiva and the lacrimal sac. Among other causes, microbes often enter the cornea through minute injuries that cause infection and trigger eye disease. Affected suffer mostly from different impairments of vision, not infrequently accompanied by eye pain. Appropriate treatment options can only be determined by an ophthalmological examination. The medical control of the disease also helps to prevent possible complications of corneal inflammation.

contents

• Inflammation of the cornea - keratitis
• A short overview
• definition
• symptoms
• causes
• diagnosis
• treatment
• Naturopathic treatment
• Current state of research

A short overview

The following brief summary provides a first overview of the symptoms, causes, and treatment options of corneal inflammation and provides important facts about disease prevention. In addition, the article contains detailed information about the clinical picture of keratitis.

Corneal inflammation is a dangerous eye disease. In severe cases, vision may be permanently impaired, for example by persistent corneal clouding. (Image: Alessandro Grandini / fotolia.com)

How to recognize a corneal inflammation?

The symptoms of corneal inflammation are manifold. The most important and common signs include the following complaints:

• red, watery and aching eyes,
• Scratching the eyes (feeling of sand in the eye),
• watery to purulent secretions in the eye,
• photophobia,
• Impaired vision.

Any kind of eye discomfort, or suspected corneal inflammation, must always be examined by a specialist to make an accurate diagnosis.

What are the causes and how can they be treated??

Various causes can cause corneal inflammation. Often these are bacterial infections. But even viruses, or more rarely fungi and other pathogens, come as a disease trigger into consideration. In most cases, the defense mechanism is already impaired or there is a corneal injury. Other non-infectious causes include, for example, dry eyes and external stimuli such as UV radiation, allergens or foreign bodies that reach the eye. Also, some pre-existing diseases favor the occurrence of corneal inflammation.

Possibilities of prevention

As far as possible you can prevent keratitis by regular eye examinations, a basic protection of the eyes and appropriate hygiene. Especially with an increased risk of underlying diseases, and especially with the use of contact lenses, the following measures are important:

• ophthalmological check-ups,
• professional use of contact lenses, especially with regard to cleaning and wearing time,
• General hygiene measures, such as hand washing and the cleanest possible storage of substances that come into contact with the eye,
• limited duration of activities on the computer or screen,
• Wearing (sun) goggles.

Working too long on the computer can cause eye irritation that causes keratitis. (Image: Ralf Geithe / fotolia.com)

definition

Corneal inflammation is also called keratitis in professional circles. This term derives from the Greek term "keratos" for cornea. In this eye disease, inflammatory processes of one or more layers of the cornea (cornea) occur in the eye.

The cornea consists of six individual layers and membranes containing innumerable small nerve endings. It is the transparent part of the outer eye skin and covers the iris (the iris), the pupil and the anterior chamber of the eye. It is also considered the "window" of the eyeball, as a clear and well-wetted cornea is the basic requirement for sharp vision. Together with the lens, the cornea is responsible for the refraction of light and also plays an important role in the protection and stability of the eye. In case of an injury or corneal disease, important functions of the eye are disturbed and vision is impaired.

The causes of the disease are manifold. Frequently, pathogens such as bacteria, viruses or fungi cause inflammation. But other stimuli or injuries can cause keratitis. Depending on the cause, different courses of disease develop with different symptoms and manifestations. Corneal inflammation occurs less frequently than conjunctivitis (conjunctivitis) and is basically the more dangerous eye disease, as vision can be permanently impaired.

symptoms

A variety of symptoms are associated with corneal inflammation. As with conjunctivitis, even in this disease of the eyes the causes are crucial for the nature and severity of the symptoms. The following symptoms may be associated with keratitis:

• redness,
• lacrimation,
• watery to purulent discharges (secretions),
• Scratching the eyes (foreign body sensation, feeling of sand in the eye),
• (strong) eye pain,
• Ulcer on the cornea (corneal ulcer),
• Photosensitivity (photophobia),
• convulsive eyelid closure (blepharospasm),
• Corneal opacity,
• Impaired vision.

The cornea of ​​the human eye consists of several layers. The severity of the symptoms of keratitis depends on how deep the inflammation is. (Image: bilderzwerg / fotolia.com)

Not infrequently, the corneal inflammation on the surrounding structures. If the conjunctiva is also affected, it is called a "keratoconjunctivitis". In this form, there is usually an increased redness and secretion.

If bacterial corneal inflammation occurs, pus accumulation may occur in the anterior chamber of the eye. In the case of a deep penetration of the germs, a so-called "creeping" corneal ulcer may also form within a short time (Ulcus serpens cornea). In this form of the disease, the breakthrough of the cornea (corneal perforation) is possible. These are serious consequences that endanger the eyesight.

causes

Most commonly, corneal inflammation is caused by bacteria. But even infections by viruses can trigger the disease. Other germs, such as fungi or amoebae, are very rare as pathogens. An intact cornea usually has a good defense mechanism, so that the registered in the eye germs usually cause inflammation only in an already damaged cornea. However, an infection is not always the trigger for keratitis, other causes are also considered.

Infectious keratitis

The typical bacteria causing infectious keratitis are also known to be associated with conjunctivitis. Often it is staphylococci, streptococci or pneumococci that enter the eye and ignite the surface of the cornea. For deeper inflammations of the cornea, small injuries usually have to be present, which serve the germs as entry portal.

A risk factor for inflammation of the cornea by bacteria is the (inappropriate) use of contact lenses. Pathogens can accumulate on contact lenses and even multiply. If these germs are not removed by proper cleaning with a care solution prior to inserting the lens into the eye, the pathogens can infect the cornea. Too long wearing of the contact lenses represents a risk in this context.

Corneal infections are often caused by germs that adhere to the contact lenses. Careful cleaning of the lenses prevents keratitis. (Image: Valerie Potapova / fotolia.com)

Bacterial corneal inflammation often affects older people or people with a corresponding underlying disease, such as diabetes (diabetes mellitus), a tumor disease, an HIV infection or an autoimmune disease. Often, in this context, a general immunodeficiency is the favoring risk factor.

In addition to bacteria but also viruses can trigger the disease. In a so-called viral keratitis are usually infections by herpes simplex virus, varicella-zoster virus or adenoviruses.

Corneal inflammation caused by herpesviruses is usually the herpes simplex virus type 1 (HSV-1), which almost all Germans carry. However, if the immune system is intact, usually no symptoms appear. If it comes to an infection with complaints, then this occurs mostly as herpes in the mouth (also called cold sores) in appearance. If, however, the eye is attacked by the viruses, this is also known under the term ocular herpes. Here, the cornea is most often affected. It can either be a primary infection or a recurrent infection (recurrence), in which the virus was already present in the organism and (for example) by a weakened immune system (again) is activated. Once the virus is in the human body, it remains in the body's cells for life, such as the nerve cells. So they can cause inflammation of the cornea via the nerve fibers.

This condition is associated with three different manifestations, depending on which layers of the cornea are affected. Keratitis dendritica (epithelial keratitis) is the superficial form that typically attacks the uppermost epithelial layer and is associated with a foreign body sensation, photophobia, and eye pain. If deeper layers are involved, it is either keratitis herpetica interstitialis (stromal keratitis) or keratitis disciformis (endothelial keratitis). In this case, impairments of vision occur. Multiple diseases of the cornea caused by herpes viruses can lead to scarring and reduced vision.

The varicella-zoster virus (VZV), in addition to the well-known chickenpox in a primary infection, as a long-term consequence of the syndrome of a herpes zoster (shingles) cause. The VZV, like herpes simplex, is also a human pathogenic herpesvirus. Most often, a shingles, starting from the spine, occurs belt-shaped along the infected nerve tract. However, if the eyeball nerve (ophthalmic nerve) is affected, face and eyes are affected and one speaks of a facial rose (zoster ophthalmicus). The eye infection is painful and months or even years later, the cornea may swell and become scarred by further damage.

Anyone who has once been infected with the varicella-zoster virus, can subsequently get a chickenpox disease, including a herpes infection that affects the eye and the cornea affected. (Image: Dan Race / fotolia.com)

When it comes to adenoviruses, the conjunctiva and the cornea are usually affected. This is also called a keratoconjunctivitis epidemica. Usually, this form of the disease begins one-sided and with a foreign body sensation. The complaints then spread quickly to both eyes. The inflammation of the connective and cornea is accompanied by swelling, tears and a photophobia. Visual impairment, for example, persistent corneal opacities, can last for months.

Much rarer than the aforementioned viruses and bacteria are other pathogens into consideration, also fungi (Aspergillus and Candida albicans Candida albicans) or about amoebae. The latter are tiny unicellular organisms that can be transferred, for example, via contaminated water. Known are the so-called Akanthamöben that can trigger the eponymous keratitis. Left untreated, this can have serious consequences.

Non-infectious keratitis

Corneal infections that are not triggered by infections are not contagious. The causes include above all dry eyes and external stimuli such as foreign bodies, UV-steels or allergy-causing substances (allergens).

Dry eyes are formed when the conjunctiva and the cornea are no longer sufficiently covered with the necessary tear layer. This can be caused, for example, by inadequate tear production or facial paralysis (with the loss of complete closure of the eyelid). Women in and after menopause are often affected by hormonal changes, dry eyes. But even long periods on the computer and on screens can lead to dryness of the eyes. Irritation and photosensitivity are the consequences of dry cornea (keratitis sicca) and conjunctiva (keratoconjunctivitis sicca). The resulting inflammation often causes itching and burning of the eyes. Dry eyes are also a symptom of Sjögren syndrome, which also causes severe dryness of the mouth and other mucous membranes. Are affected only mouth and eyes is the so-called sicca syndrome. The cornea can be severely damaged.

A corneal inflammation caused by UV rays (keratitis photoelectrica), for example, after strong exposure to light, such as in the mountains or when welding without further use of sun or goggles occur. This can lead to a very painful inflammation. Foreign bodies often reach the eye through the insertion of contact lenses. Allergies are mostly pollen allergies and hay fever.

With the help of the slit lamp and fluorescent dyes, changes in the cornea are clearly visible. (Image: mmphoto / fotolia.com)

diagnosis

For complaints suggestive of corneal inflammation, ophthalmological examination should be performed (as in conjunctivitis). Early medical consultations usually prevent complications and complications that permanently affect vision.

During the patient survey (anamnesis) it is mainly clarified which symptoms are present and since when or if they occur for the first time. In addition, the visual acuity and possible impairments of vision are checked. In the further investigation, the cornea is examined with the aid of a slit lamp. At a high magnification, and optionally with the additional use of special fluorescent dyes (fluorescein), disease symptoms and other changes or injuries in the different layers of the cornea can be detected quickly. If necessary, pathogens such as bacteria and fungi can be precisely determined by means of a smear. The exact identification of viruses is more difficult.

With the help of the so-called Schirmer test, a suspicion of dry eyes can be confirmed. In this type of examination, special filter paper strips are used to test whether there is sufficient tear fluid to nourish the eyes.

The knowledge gained plays an important role in the decision-making process for the right treatment.

treatment

Depending on the cause or the pathogens, it is treated locally with different medications in the form of eye drops, ointments or gels. The most common antibiotic eye drops are used to fight a variety of bacteria (broad spectrum antibiotics). But also antifungals (against fungi) or antivirals (against viruses) are used. In the case of herpes viruses, acyclovir is usually prescribed, often in a combination of eye drops and tablets.

Depending on the ingredients, eye drops can kill certain germs (for example, antibiotic drops) or stabilize the tear film. (Image: Cpro / fotolia.com)

Artificial tears are non-antibiotic eye drops used in dry eyes. By additional moistening of the eyes, the tear film should be stabilized and the complaints should be alleviated. A basic eye care, for example by wearing sunglasses or darkening the room, relieves further discomfort.

If the therapy works well, keratitis is over within one to two weeks. For more severe disease manifestations, however, healing may take longer.

If an ulcer (corneal ulcer) occurs during keratitis, there is an acute threat to the eye and its functions. This is an emergency situation and requires immediate medical attention to prevent serious consequences. Under certain circumstances, a hospital inpatient therapy is necessary. In severe cases, it may also require a corneal transplant (keratoplasty). Another surgical intervention is amniotic membrane grafting, which is used for more severe and permanent corneal epithelial defects. As a membrane replacement or as a temporary graft, the amniotic membrane is used on the eye. There it has anti-inflammatory and anti-scarring properties. So the healing process can be accelerated. In all forms of therapy scarring of the cornea is not excluded.

Naturopathic treatment

Corneal inflammation is a dangerous condition that always requires medical attention and control. Effective home remedies from natural medicine can be used as supportive measures to relieve acute symptoms. Many of these symptoms, which occur with corneal inflammation, also occur in conjunction with conjunctivitis. Frequently, the use of tea infusions of fennel and eyebright (Euphrasia) is recommended. Chamomile should rather not be used on the eye as it irritates the mucous membranes and can even intensify existing inflammatory processes. Detailed information on natural home remedies can be found in another article.

If complications occur, surgical procedures such as cornea transplantation are often the last resort to maintain vision. (Image: romaset / fotolia.com)

Current state of research

Previous forms of therapy for corneal inflammation do not always promise a successful cure and it comes repeatedly to complications and sequelae. According to the World Health Organization, corneal infections are a major cause of visual acuity reduction worldwide and one in four blindness is probably due to corneal clouding. Researchers are countering this with the search for alternative treatment concepts. In this context, the Fraunhofer-Gesellschaft is pursuing the novel approach of treating microbial corneal inflammation with germicidal contact lenses. The therapeutic lenses are treated with plasma-activated water (PAW) to control pathogens without damaging the cornea. Initial tests have already been promising, but clinical trials are pending. (jvs, cs; updated on 01.09.2018)