Neurotrophic keratitis – causes, treatment options

The common herpes virus can cause an incurable eye disease that often leads to blindness. Currently, clinical trials of a new drug for this disease are underway in Poland.

Patients suffering from neurotrophic keratitis caused, among others, by because of the herpes virus, they stop seeing. Some people have such visual impairment that they can only see the light and the movement of the hand in front of their eyes. The disease destroys the outer layer of the eye – the cornea.

Cornea with nerves

– The cornea can be compared to a watch fastener – says the ophthalmologist prof. Jacek P. Szaflik. It protects the eye and focuses the light rays at the same time. Since it must be transparent, there are no blood vessels in it. It is, however, the most innervated organ in the body – almost 400 times more than the skin. Thanks to this, it perfectly responds to external factors. For example, if a foreign body is on the cornea, the nerves immediately send out a signal that stimulates the production of tears. The outer layer of the cornea is covered with epithelium, which exfoliates and regenerates. Thanks to this, a healthy eye can repair its damage within 24 hours. The epithelium is covered with the so-called tear film, which includes substances that protect the eye against viruses and bacteria.

Blinding virus

Unfortunately, the common virus that causes herpes can destroy the cornea. It can cause neutrophic inflammation, which damages its innervation. The nerves in the cornea can be completely degraded and therefore stop working properly. As a result, it may break. The patient loses sight and sometimes the eye. Neutrophic inflammation can also occur as a result of diabetes or neurosurgery. Prof. Szaflik tells the story of a man who developed herpes on his eye. “It was red, painful, and the patient saw worse,” he says. He was given oral herpes medications and an ophthalmic ointment. A few months after the treatment, the patient again complained that his vision was worse, and the cured eye turned red. During the examination in the ophthalmological office, it turned out that the corneal epithelium was damaged. The patient went to Professor Szaflik. – When suspecting neutrophic keratitis, we diagnose the state of its innervation. The simplest examination is to touch the cornea with a sterile gauze and see if the patient feels it. We also have a special microscope, the so-called confocal, in which we can see if the nerves have been damaged – explains the ophthalmologist.

Incurable for now

Unfortunately, neutrophic keratitis is an incurable disease. – We treat patients symptomatically, which means that we are trying to heal the cornea. We patch holes, but we are not able to stop the process of nerve degeneration – says Prof. Dishpan. He says that in the past, in order to stop the process of cornea destruction, patients’ eyelids were stitched, covering the eye. “It was an effective, but quite drastic way,” he says. – Today, one of the methods of treatment is suturing the amniotic membrane on the cornea from the placenta of the fetus. You can also transplant a patient with a cornea from a deceased donor. However, the prognosis is not good, because the disease can still destroy the nerves in the cornea, explains the ophthalmologist.

Hope for the sick

Clinical trials of a new drug for neutrophic keratitis are starting at the Clinical Ophthalmology Hospital of the Medical University of Warsaw in Warsaw. It is a biological drug – human nerve growth factor. Prof. Szaflik says preliminary research conducted abroad has produced very promising results. In most of the patients taking part in them, complete resolution of the corneal lesions was observed. In others, a significant improvement in her condition. – This is a great chance for patients who, as a result of disease, saw only 10% of what was healthy. One of my patients is fifty years old and sees only the movement of a hand in front of his eyes. This is a real drama – he says. – Let’s hope that the research will confirm the effectiveness of the drug and in a few years this disease will cease to be incurable – he adds.

Tekst: Halina of Pilon