NK is a disease with a prevalence of less than 5 cases/10,000 population, being more precise than 4.2 cases/10,000 inhabitants, although it should be noted that the exact incidence and prevalence are not yet available in the literature, and that even these approximations seem to overestimate the real numbers.  In fact, said prevalence was estimated and extrapolated from the available evidence regarding the conditions most associated with said pathology, being reported as low as 1.6 cases/10,000 inhabitants, with respect to estimates on herpetic keratitis (1.22/ 10,000) and the post-surgical state with damage to the trigeminal nerve (0.02/10,000) . Currently, neurotrophic keratitis develops on average in 6% of herpetic keratitis, which in turn have a prevalence of 149/10,000  as well as in 12.8% of herpes zoster keratitis, the latter presenting a prevalence of 26/100,000 . Other common causes are neurosurgical procedures to treat neuralgia of the trigeminal nerve, which tends to damage said nerve in 2.8% of cases, with a prevalence of 1.5/10,000 and therefore the previously mentioned estimated prevalence (0.02/10,000) . Unfortunately, there is still no evidence in the literature on the incidence and/or prevalence of other common associated conditions such as chemical burns, diabetes, contact lens wear, as well as less frequent associated causes such as intracranial masses, space occupants, multiple sclerosis, or leprosy [12, 18]. A recent retrospective, observational study at an ophthalmology center in Paris, France screened more than 300,000 patients and reported an incidence of 11/10,000 patients. . Similar to what has been reported in the literature was found in our population. Likewise, age was also expected from what was reported. It is important to mention that the antecedent that occurred most frequently was the use of topical medications, which represents an important focus of attention for treating physicians since these patients could present a higher risk of developing neurotrophic keratitis.
Any condition that alters the innervation of the trigeminal nerve towards the cornea at any of the levels of this circuit, from the nucleus to the free nerve endings, can eventually generate neurotrophic keratitis, an entity with specific diagnostic characteristics and totally independent of the basic medical history of the patient at that time , and it can include causes as diverse as those concerning ocular surface diseases, systemic pathologies and both peripheral and central nerve damage [2, 20]. The most common causes of neurotrophic keratitis are attributed to both herpes simplex virus as well as herpes zoster virus with a proportion ranging from 27–32% of cases [6, 7, 8]. In our population we found a higher proportion of herpes virus infection, with 19% of patients diagnosed with neurotrophic keratitis. Other local conditions associated with this disease are chemical, thermal, and traumatic ocular burns, the use of contact lenses, corneal dystrophies, and the chronic use of topical medications such as anesthetics, beta-blockers, antivirals, antibiotics, NSAIDs and glaucoma treatment [2, 17]. Surgical procedures that involve the cornea, such as refractive surgery, keratoplasty and its derivatives, and cataract surgery, are also associated with their respective alteration to the trigeminal innervation of the treated area [9, 10, 20]. In addition, therapeutic surgeries for trigeminal neuralgia are strongly related to the disease, such as microvascular decompression, balloon compression, radiofrequency thermocoagulation, and gamma laser knife radiosurgery.
NK is a chronic disease with an insidious evolution, which is interesting due to the diversity of clinical characteristics it presents. In our study population, it was found that 40% of patients with neurotrophic keratitis had a history of diabetes mellitus, which is important to keep in mind when treating this disease. Regarding the progress of the disease, it is important to keep in mind the clinical variety of presentation. We found the absence of eye pain, redness and constant tearing as clinical symptoms associated with the progress of the disease, which is consistent with what is reported in the literature , so this pathology should be sought intentionally when encountering the clinical symptoms described above. One of the limitations of this study is the size of the sample, which although it exceeds what was expected, could be increased even more if the registry of patients from both public and private hospitals in the locality is analyzed.