Corneal nerves are responsible for maintaining the anatomical and functional integrity of the cornea, conveying tactile, temperature and pain sensations, playing a role in the blink reflex, in wound healing and in the production and secretion of tears.
[7] Congenital or acquired ocular and systemic diseases[8] can determine a lesion at different levels of the trigeminal nerve, which can lead to a reduction (hypoesthesia) or loss (anesthesia) of sensitivity of the cornea.
Other, albeit less frequent, potential causes of the disease are: intracranial space-occupying lesions such as neuroma, meningioma and aneurysms, which may compress the trigeminal nerve and reduce corneal sensitivity.
With regard to the patient's medical history, special attention should be paid to any herpes virus infections and possible surgeries on the cornea, trauma, abuse of anaesthetics or chronic topical treatments, chemical burns or, use of contact lenses.
[citation needed] In stage I, the least serious, treatment consists of the administration of preservative-free artificial tears several times a day in order to lubricate and protect the ocular surface, improving the quality of the epithelium and preventing the possible loss of transparency of the cornea.
[22] In the most severe forms (stage III), it is necessary to stop the progression towards corneal perforation: in these cases, a possible surgical treatment option is tarsorrhaphy, i.e. the temporary or permanent closure of the eyelids by means of sutures or botulinum toxin injection.
[23] In addition, another viable therapeutic option is amniotic membrane graft, which has recently been shown to play a role in stimulating corneal epithelium healing and in reducing vascularisation and inflammation of the ocular surface.