Neurotrophic keratopathy is a disease of the eye, particularly its cornea (medically cornea). It is caused by damage to the very sensitive nervous tissue there, with serious consequences for the entire eye. In science, the term keratitis neuroparalytica is usually used. The ICD-10 classification is H16.2.
What is neurotrophic keratopathy?
The focus of neurotrophic keratopathy is the cornea. It is part of the outer skin of the eye and thus also the closure of the entire eyeball. Usually, it shows clearly with a complete layer of tear fluid. Its curvature ensures that incident light is refracted and is therefore important for correct vision. The cornea is traversed by a multitude of nerves and is therefore considered one of the most sensitive structures of the body in terms of temperature, pain and touch. The nerves originate in the ophthalmic nerve, a secondary branch of the trigeminal nerve. If this nerve or the individual nerves in the cornea are directly damaged, neurotrophic keratopathy may develop. However, only a few patients are affected. In Europe alone, just 0.05 percent of the entire population has been diagnosed with one of the three defined severity levels of the disease.
Causes
The main cause of neurotrophic keratopathy is decreased secretion of tear fluid caused by nerve damage, which normally supplies the cornea with sufficient nutrients while providing a secure protective shield. If there is a disturbance in this area, degenerative changes occur. Possible are various degenerations, restrictions in the functioning, regressions as well as in severe cases corneal ulcers (medically Ulcus corneae). The wound healing of the cornea is disturbed at the same time. Triggers for the damage of the nerves are in almost twenty percent of all cases herpes viruses and the infections triggered by them. In addition, physical injuries, chemical burns, the incorrect use of contact lenses or errors during surgical procedures are also possible causes. Less frequently, however, underlying diseases such as diabetes mellitus, multiple sclerosis or leprosy are responsible for the disease. The same applies to various tumors, cysts and abscesses. Congenital eye diseases, on the other hand, hardly play a role in the formation of neurotrophic keratopathy.
Symptoms, complaints, and signs
Neurotrophic keratopathy generally manifests itself in a fairly indeterminate manner. Most symptoms also occur in other diseases of the eye and cannot be clearly attributed to neurotrophic keratopathy. However, the clearest sign of the disease is the reduced sensitivity of the cornea. As a result, certain stimuli, such as touch or temperature differences, are hardly or not at all perceived by the patient. Affected persons are therefore pain-free even in a severe stage of the disease. Neurotrophic keratopathy becomes visible by a pronounced opacity of the otherwise clear cornea. Furthermore, a conspicuous reddening of the eye and a diminished blink reflex can be detected. Patients’ visual acuity may fluctuate somewhat in the early stages. However, the more severe the progression of the disease, the weaker the visual acuity of the affected eye becomes.
Diagnosis and course of the disease
To diagnose neurotrophic keratopathy, first, a thorough history should be taken to determine the cause. On the other hand, various medical examinations, such as a sensitivity test of the cornea or a functional test of the tear film, are necessary. Due to the ambiguous symptoms, a particularly careful examination is obligatory in order to prevent the progression of the disease as early as possible. If left untreated, neurotrophic keratopathy can lead to corneal ulceration, loss or at least perforation of the cornea, or so-called aseptic necrosis. It can cause concomitant changes in the conjunctiva even in mild cases and, at a later stage, pose a threat to the entire eye.
Complications
Neurotrophic keratopathy can lead to severe complications, especially in the third stage. Because the disease is not accompanied by pain, it is often not recognized until it is too late.Therefore, even occasional fluctuations in visual acuity should give reason to urgently consult a doctor in order to avoid complete destruction of the cornea. In the course of the disease, there is always a risk of bacterial superinfection. In this case, the cornea is attacked not only by viruses but also by bacteria and fungi. As a consequence, a so-called corneal ulcer can develop. Corneal ulcer is a corneal ulcer characterized by painful and constantly watering eyes. The discharged secretion may even contain pus, which indicates a bacterial infection. The eye is then inflamed and very sensitive to light. Sometimes eyelid spasm is also observed, which is characterized by excessive blinking on both sides during fatigue, emotional tension or bright light stimuli. Eyelid spasm may even cause closure of the eyes for several hours. Overall, visual acuity (visual sharpness) worsens in corneal ulcers. In severe cases, perforation of the cornea may occur. This poses a great threat to the eye and can lead to blindness. To prevent this serious complication, surgical intervention is necessary in addition to comprehensive antibiotic treatment.
When should you see a doctor?
When visual disturbances, eye pain, and other known signs of neurotrophic keratopathy are noticed, a visit to the doctor is indicated. If physical complaints occur without a clear cause being found, a clarifying consultation with the family doctor is necessary. This applies in particular to increasing eye complaints or increased sensitivity of the cornea. Repeated tearing as well as swelling in the area of the eyes are best clarified immediately. The doctor can diagnose neurotrophic keratopathy and, if necessary, start treatment directly or refer the patient to a specialist. Those at risk include people who have recently contracted a viral infection or ocular herpes zoster. Victims of physical injuries and chemical burns should also consult their doctor if they have symptoms mentioned above. Anyone suffering from the aforementioned symptoms after a surgical or neurosurgical procedure is best to inform the doctor in charge. The same applies if the symptoms occur after the use of contact lenses or tropical medicines. Diabetes, leprosy and multiple sclerosis patients should inform the responsible medical practitioner about unusual symptoms in the eye area. Neurotrophic keratopathy is treated by the ophthalmologist or an internist. Severely ill patients must be treated in a specialized clinic.
Treatment and therapy
The treatment of neurotrophic keratopathy remains difficult and depends entirely on the individual manifestation in the patient. Optimal success is rarely achievable with current therapies, he said, and thus the primary focus is on preventing the disease from spreading. This is mainly achieved by the administration of non-preserved tear substitute fluid to resupply the cornea with sufficient nutrients. In some cases, special proprietary serum eye drops prepared from the patient’s blood serum are useful for this purpose. Therapeutic contact lenses can be worn to protect the cornea. Alternatively, surgery can be performed to close all or part of the eyelid or an amniotic graft can be sutured to the cornea. Parallel inflammation is generally treated with a special eye ointment or gel. Existing ulcers often reduce with the administration of antibiotics. The choice here is between tablet form and local application. If neurotrophic keratopathy is based on a specific underlying disease, a two-pronged therapy is necessary for the patient. Here it is necessary to stop the spread of the corneal damage and at the same time to combat the actual cause. This applies, for example, to diabetes mellitus or multiple sclerosis, as well as to the removal of triggering tumors or cysts.
Outlook and prognosis
The prognosis for patients with neurotrophic keratopathy depends on the presenting cause. If a chemical burn is present, the damage is usually irreversible and no cure is possible. If a viral disease is present, medication must be administered to prevent the virus from spreading and to kill it at the same time.Normally, the affected person suffers from further discomfort, which subsequently usually recedes completely. In the case of cysts and abscesses, surgical intervention is often necessary to enable improvement. If the affected person suffers from a tumor, the further course of the disease is determined by the progress of the disease as well as the treatment options. In an advanced stage of the disease, the patient is threatened with premature death despite all efforts. If neurotrophic keratopathy is triggered by the incorrect use of visual aids, a change in the use of the aids is necessary. Otherwise, an increase in symptoms is possible. Overall, treatment options for those affected usually result in relief of existing irregularities, but not always in a complete cure. The best possible results are achieved if a diagnosis is made and therapy is started as soon as the first health irregularities occur. Doctors often strive to contain the progress of the disease and minimize the risk of secondary health problems. Without treatment, there will be an increase in symptoms.
Prevention
The most important preventive measure for neurotrophic keratopathy is to protect the cornea and avoid injury. Attention should be paid to proper use of contact lenses, wearing protective eyewear in dangerous situations, and the risks of voluntary laser treatment for refractive errors. Careful hygiene and regular checkups with an ophthalmologist are also important.
Aftercare
Because the damage done to the nerve is usually not curable, neurotrophic keratopathy persists throughout life. Therefore, therapy adapted to the stage of the disease is usually part of the patient’s daily routine. Due to the lack of sensitivity of the cornea, exacerbations of neurotrophic keratopathy are not always noticed. Constant controls by an expert ophthalmologist are therefore obligatory. The ophthalmologist can record and document the course of the disease by measuring the visual acuity. If corneal lesions occur repeatedly, further therapeutic measures may be necessary. These protect the cornea and prevent the occurrence of tumors. Since the cornea is no longer as resistant in neurotrophic keratopathy, it should be specially protected in the future. This includes wearing protective eyewear during hazardous activities, avoiding bright light sources, and proper circumference with contact lenses. Patients should also make sure to take adequate rest breaks between heavy exertion of the eye. This includes working in low brightness or constantly looking at a screen. Drinking protocols help monitor and optimize daily fluid intake. This ensures that the eye is supplied with sufficient tear fluid. All these preventive measures can favorably influence the course of the disease, but do not replace a regular visit to the doctor.
What you can do yourself
In everyday life, the eye should not be exposed to bright light sources. Looking directly into the sun or into bright spotlights of a lamp should be avoided. The process can cause injury to the eye and further aggravate existing symptoms. In addition, when reading or working at a computer screen, care should be taken to ensure that the environment is not too dark. This circumstance also leads to an overload of the optic nerve and to discomfort. If the affected person notices that too much strain has been placed on the eye, breaks should be taken immediately. The eye should be given the opportunity to regenerate during rest periods. During this time, no activities such as reading, writing or watching television should take place. To ensure that the eye is always supplied with a sufficient amount of tear fluid, the daily intake of beverages should be monitored and optimized if necessary. As soon as dryness in the eye is noticed, the affected person should react. In case of injuries in the area of the eye, it is always necessary to consult a doctor. Likewise, if there are fluctuations in vision, a follow-up visit should be initiated. Self-help measures are not sufficient to adequately determine whether defects of the sensitive area have occurred. Only through accurate measurement of vision can abnormalities and irregularities be detected and documented.
