Diagnosis and management of neurotrophic keratitis

Corneal neurotization for neurotrophic keratopathy: Review of surgical techniques and outcomes

Neurotrophic keratopathy is a degenerative disease in which damage to the corneal nerves leads to corneal hypoesthesia. Injuries to neurotrophic corneas are notoriously difficult to treat and have traditionally been approached with supportive management. However, recent progress in the field of corneal neurotization has given new direction for addressing nerve loss directly by stimulating new nerve growth onto the cornea from nearby sensory nerves transferred to the perilimbal region. Herein, we review the surgical techniques utilized in corneal neurotization, including direct transfers and the use of nerve grafts. Considerations in surgical approach, as well as factors that influence prognosis and outcomes of the surgical intervention are also discussed.

Neurotrophic Keratopathy in Pediatric Patients

Purpose: This review provides an overview of the causes and treatment of neurotrophic keratopathy in the pediatric population.Methods: A thorough review of the current literature discussing neurotrophic keratopathy was conducted then summarized.Results:Fourty-nine papers were reviewed. Congenital and acquired causes of neurotrophic keratopathy exist in the pediatric population. Both medical and surgical approaches to treatment have been trialed, albeit to a limited extent, in pediatric patients. Conservative treatment includes topical lubrication and antibiotics to prevent concurrent infectious ulcer formation. Various neurotrophic factors have been trialed in the form of serum drops to restore corneal sensation when conservative measures fail. Surgically, different corneal neurotization techniques have been developed whereby a donor nerve is routed to the anesthetized cornea to restore innervation and sensation. Conclusions: Advances in the treatment of neurotrophic keratopathy have made corneal reinnervation and restoration of vision more easily attainable in pediatric patients.

Neurotrophic keratitis after penetrating keratoplasty for lattice dystrophy

Purpose

To report clinical outcomes of a patient with unilateral neurotrophic keratitis following penetrating keratoplasty for lattice dystrophy treated with topical recombinant human nerve growth factor.

Observations

A 75-year-old male with lattice dystrophy and history of herpes simplex keratitis, presented with recurrent neurotrophic ulceration in the right eye two years following penetrating keratoplasty. The patient was successfully treated with topical recombinant human nerve growth factor.

Conclusion

Neurotrophic keratitis is a rare chronic disorder that affects quality of life due to the risk of vision loss. Topical recombinant human nerve growth factor is a novel and effective treatment option that may help improve optical quality and patient's satisfaction as shown in this case of recurrent neurotrophic keratitis.

Advances in the Medical Management of Neurotrophic Keratitis

Neurotrophic Keratitis (NK) is a degenerative disorder of the cornea characterized by decreased or absent sensory corneal innervation, corneal epitheliopathy and impaired healing.The clinical presentation of NK can range from persistent epithelial defects to corneal perforation and management is often both challenging and protracted. Historically, the management of NK has consisted of non-specific strategies to facilitate corneal epithelial healing such as lubrication, bandage contact lenses and tarsorrhaphy. Recent advances in the development of therapeutics for NK have provided new and efficacious targeted strategies for its management.In this article, we review recombinant human nerve growth factor (Cenegermin), currently approved for clinical use in the United States and Europe, as well as other promising therapeutic options that are in pre-clinical development such as thymosine β4, connexin43 inhibitors, and artificial extracellular matrix components.

Evaluation of Clinical and Histological Outcomes of Adipose-Derived Mesenchymal Stem Cells in a Rabbit Corneal Alkali Burn Model

To assess effects of adipose-derived mesenchymal stem cells (AMSCs) in corneal alkali injuries in an experimental animal model. Twenty white New Zealand rabbits were included in the study. The animal models were randomly divided into 2 groups. Rabbits in the AMSC group (n = 10) received an intrastromal, a subconjunctival injection, and topical instillation of 0.5 ml totally of phosphate-buffered saline (PBS) containing 2 × 10⁶ AMSCs. In the control group (n = 10), rabbits received only 0.5 ml of PBS using the same methods. A masked investigator measured the corneal sensation, anterior chamber Inflammation (ACI), and conjunctival congestion. Additionally, a blind histological and immunohistochemical evaluation was made. In the AMSC group, the central corneal sensation was increased whereas ACI and conjunctival congestion were reduced compared to the control group in the 28 days of follow-up (p < 0.05). A statistically significant difference (p < 0.05) was noted between the two groups as recorded in the above parameters. Histological analysis showed that pathological vascularization was markedly reduced in the AMSC group which was consistent with the absence of factor VIII in the immunohistochemistry sections. There is a trend towards improved clinical outcomes including corneal sensation as well as acceleration in the restoration of normal corneal architecture in corneal alkali burns treated with AMSCs, results that support the need for further research in the field.

Pathobiology and treatment of viral keratitis

Keratitis is one of the most prevalent ocular diseases manifested by partial or total loss of vision. Amongst infectious (viz., microbes including bacteria, fungi, amebae, and viruses) and non-infectious (viz., eye trauma, chemical exposure, and ultraviolet exposure, contact lens) risk factors, viral keratitis has been demonstrated as one of the leading causes of corneal opacity. While many viruses have been shown to cause keratitis (such as rhabdoviruses, coxsackieviruses, etc.), herpesviruses are the predominant etiologic agent of viral keratitis. This chapter will summarize current knowledge on the prevalence, diagnosis, and pathobiology of viral keratitis. Virus-mediated immunomodulation of host innate and adaptive immune components is critical for viral persistence, and dysfunctional immune responses may cause destruction of ocular tissues leading to keratitis. Immunosuppressed or immunocompromised individuals may display recurring disease with pronounced severity. Early diagnosis of viral keratitis is beneficial for disease management and response to treatment. Finally, we have discussed current and emerging therapies to treat viral keratitis.

Predicting Factors Influencing Visual Function of the Eye in Patients with Unresolved Facial Nerve Palsy after Upper Eyelid Gold Weight Loading

Implantation of gold weights into the upper eyelid is a proven method of treating lagophthalmos and exposure keratopathy in patients with unresolved facial nerve palsy. The aim of this study was to evaluate the factors affecting visual acuity and corneal complications in patients after upper eyelid gold weight lid loading. Material and methods: This prospective consecutive clinical study was conducted in years 2012–2018. In total, 59 people (40 women, 19 men aged 55.5 ± 17.4 years) meeting the inclusion criteria were treated with gold weights. The ordered multinomial logit model was used to analyze the factors affecting best-corrected visual acuity (BCVA) and degree of exposure keratopathy after surgery. The influence of the following variables was analyzed: patient age, etiology and duration of the facial nerve palsy, history of the previous eyelid surgery, degree of lagophthalmos in mm, presence of Bell’s phenomenon, and corneal sensation, Schirmer test results. Results: Implantation of gold weights into the upper eyelid effectively reduced lagophthalmos and exposure keratopathy in the study group (p < 0.001). BCVA was maintained or better in 95% of patients after surgery. Patient age, presence of the Bell’s phenomenon, and corneal sensation significantly affected the final BCVA (p < 0.1). The presence of Bell’s phenomenon and corneal sensation had a positive effect on the degree of keratopathy after surgery (p < 0.1). In turn, patient age and history of tarsorrhaphy were significant negative prognostic factors of exposure keratopathy and BCVA after surgery (p < 0.05). Etiology and duration of facial nerve palsy, degree of corneal exposure in mm, and results of the Schirmer test did not have a significant impact on the outcome after surgery (p > 0.1). Conclusions: The results of our study may help to answer the question of how to direct ophthalmologists and other specialists who refer to ophthalmologists for management advice in patients with facial nerve palsy. Elderly patients with a history of tarsorrhaphy who present with poor Bell’s phenomenon and/or a lack of corneal sensation should be the first candidates for immediate correction of lagophthalmos.

CORNEAL NEUROTIZATION IN A PATIENT WITH SEVERE NEUROTROPHIC KERATOPATHY. CASE REPORT

PURPOSE

Neurotrophic keratopathy (NK) is a degenerative corneal disease caused by damage to the trigeminal innervation due to a decrease in corneal sensitivity or complete anaesthesia. Impaired corneal innervation leads to morphological and metabolic disorders of the epithelium. In addition, it also leads to the development of recurrent or persistent epithelial defects in corneal ulcers, which may progress to stromal lysis and corneal perforation. One possible solution for severe NK is reinnervation of the anaesthetic cornea (corneal neurotization) using the supraorbital nerve and an autologous sensory nerve graft (indirect neurotization). This article presents the results of corneal neurotization in a young male patient with persistent epithelial defects and corneal ulcers due to corneal denervation.

RESULTS

A 22-year-old man with a history of neurosurgery for astrocytoma of the cerebellum and trunk on the right side at the age of 2 years, was observed for postoperative paresis of the right facial nerve with lagophthalmos in his childhood. The presence of asymptomatic dysfunction of the right trigeminal nerve was also noted. At the age of 22 years, after right eyeball contusion, the vision of the right eye decreased and a persistent epithelial defect developed, followed by corneal ulceration. Due to the exhaustion of therapeutic options in a young patient with corneal anaesthesia, the cornea was reinnervated via the contralateral supraorbital nerve using an autologous sural nerve graft. Five months after the surgery, the sensitivity of the cornea of the right eye began to recover. After amniotic membrane transplantation, the extensive epithelial defect healed, and the opaque corneal stroma gradually cleared up.

CONCLUSION

The reinnervation of the anaesthetic cornea (corneal neurotization) using the supraorbital nerve and the autologous sensory nerve graft represents a new solution for severe NK treatment. The severe corneal condition in our patient healed after the surgery.

Cenegermin: A Review in Neurotrophic Keratitis

Cenegermin (Oxervate™), an ophthalmic solution containing 20 µg/mL of recombinant human nerve growth factor (rhNGF), is the first drug to be approved for the treatment of neurotrophic keratitis (NK; also referred to as neurotrophic keratopathy). In the registration trials, the majority of adults with moderate or severe NK experienced complete corneal healing after up to 8 weeks of topical cenegermin therapy. The rate of complete corneal healing was generally higher, and that of disease progression was lower, with cenegermin than with vehicle. Although the drug provided no statistically significant benefit over vehicle in terms of corneal sensitivity or visual acuity after 8 weeks of treatment, few patients with corneal healing experienced disease recurrence over 48 weeks of follow-up. Longer-term data are needed to definitively determine the efficacy of cenegermin with respect to these outcomes; further investigation into cenegermin re-treatment following disease recurrence would also be beneficial. Cenegermin had no detrimental impact on health-related quality of life (in contrast to some surgical treatments) and was generally well tolerated. Cenegermin is thus a welcomed non-surgical treatment option approved for this rare and challenging degenerative disease.

Diabetic Corneal Neuropathy

Diabetic keratopathy (DK) is a common, but underdiagnosed, ocular complication of diabetes mellitus (DM) that has a significant economic burden. It is characterised by progressive damage of corneal nerves, due to DM-induced chronic hyperglycaemia and its associated metabolic changes. With advances in corneal nerve imaging and quantitative analytic tools, studies have shown that the severity of diabetic corneal neuropathy correlates with the status of diabetic peripheral neuropathy. The corneal nerve plexus is, therefore, considered as an important surrogate marker of diabetic peripheral neuropathy and helps in the evaluation of interventional efficacy in the management of DM. The clinical manifestations of DK depend on the disease severity and vary from decreased corneal sensitivity to sight-threatening corneal infections and neurotrophic ulcers. The severity of diabetic corneal neuropathy and resultant DK determines its management plan, and a step-wise approach is generally suggested. Future work would focus on the exploration of biomarkers for diabetic corneal neuropathy, the development of new treatment for corneal nerve protection, and the improvement in the clinical assessment, as well as current imaging technique and analysis, to help clinicians detect diabetic corneal neuropathy earlier and monitor the sub-clinical progression more reliably.

Unilateral pediatric neurotrophic keratitis due to congenital left trigeminal nerve aplasia with PROSE (prosthetic replacement of the ocular surface ecosystem) treatment

PURPOSE

To present a 3-year-old female patient with a non-familial, isolated, unilateral case of left corneal anesthesia with MRI-confirmed congenital left trigeminal nerve aplasia.

OBSERVATIONS

A corneal epithelial defect was noted in the left eye after an 8-week trial of recombinant human nerve growth factor. Subsequent evaluation and fitting of a PROSE (prosthetic replacement of the ocular surface ecosystem) lens led to healing of the corneal epithelium and visual acuity improvement from 20/300 to 20/70.

CONCLUSIONS AND IMPORTANCE

A scleral lens may be a possible treatment for those with neurotrophic keratitis in which a trial of topical lubrication and human nerve growth factor has not been effective.

A Novel Treatment for Neurotrophic Corneal Ulcer Using Topical Cenegermin (OXERVATE™) Containing Recombinant Human Nerve Growth Factor

Neurotrophic keratitis represents a complex degeneration of the cornea that can result in debilitating symptoms and serious sight-threatening complications. Patients with neurotrophic keratitis (NK) usually present with a history of corneal injury or past surgical intervention involving damage to the corneal nerves; as well as, chronic ocular surface disease. This nerve damage results in sensory loss and poor healing to the corneal tissues. This poor ability to heal results in the downward spiral of events that NK patients are subject to, which can include corneal surface breakdown, ulceration, melting, and total perforation. Treatments to attempt to support the cornea to heal and then protect it have recently advanced beyond traditional treatments and may include amniotic membrane application, autologous serum eye drops, biologic eye drops, and various other supportive treatments. Even aggressive combinations of these, and many other treatments, can leave NK patients still uncontrolled and progressing to end-stage disease that would require invasive intervention resulting in an even worse prognosis. This case report describes a patient who demonstrated all three stages of NK. Multiple interventions were initiated, including tarsorrhaphy, autologous serum eye drops, Prokera amniotic membrane, antibiotics, bandage contact lenses (BCL) therapy, and PKP. However, the patient experienced variable and transient improvement with relapse within a few weeks with recurrent and persistent epithelial erosion and stromal ulceration. A novel eye drop, cenegermin (OXERVATE^TM), an ophthalmic solution containing 20 μg/mL of a recombinant form of human nerve growth factor (NGF), was added to her treatment regimen allowing for successful management of NK and restoration of corneal integrity.

High Molecular Weight Hyaluronan Promotes Corneal Nerve Growth in Severe Dry Eyes

The purpose of this study was to investigate the effect of high molecular weight hyaluronan (HMWHA) eye drops on subbasal corneal nerves in patients suffering from severe dry eye disease (DED) and to evaluate the damage of subbasal corneal nerves associated with severe DED. Designed as an international, multicenter study, 16 patients with symptoms of at least an Ocular Surface Disease Index (OSDI) score of 33, and corneal fluorescein staining (CFS) of at least Oxford grade 3, were included and randomized into two study arms. The control group continued to use their individual optimum artificial tears over the study period of eight weeks; in the verum group, the artificial tears were substituted by eye drops containing 0.15% HMWHA. At the baseline visit, and after eight weeks, the subbasal nerve plexus of 16 patients were assessed by confocal laser scanning microscopy (CSLM). The images were submitted to a masked reading center for evaluation. Results showed a significant increase of total nerve fiber lengths (CNFL) in the HMWHA group (p = 0.030) when compared to the control group, where the total subbasal CNFL did not significantly change from baseline to week 8. We concluded that in severe DED patients, HMWHA from topically applied eye drops could cross the epithelial barrier and reach the subbasal nerve plexus, where it exercised a trophic effect.

Role of Topical Cenegermin in Management of a Cornea Transplant in a Functionally Monocular Patient with Neurotrophic Keratitis and Facial Nerve Palsy: A Case Report

Background

NK is one of the most challenging ocular conditions to treat and it can represent a devastating complication of acoustic neuroma surgery due to the profound corneal anesthesia and concomitant exposure keratopathy caused by seventh nerve palsy. In such cases, cornea surgery should be considered with extreme caution due to the high risk of devastating complications. The purpose of the study is to report the efficacy of a novel human recombinant nerve growth factor (rhNGF)-based ophthalmic treatment in a functionally monocular patient with a recurrence of severe neurotrophic keratitis (NK) on a corneal graft.

Case Presentation

A 24-year-old woman who underwent acoustic neuroma surgery was referred for the assessment of a lagophthalmos and a paracentral corneal ulcer refractory to medical treatment. The patient presented with a large descemetocele, diagnosed as stage 3 NK that required multilayer amniotic membrane transplantation (AMT) and a following optical penetrating keratoplasty (PK). The recurrence of NK on the graft was successfully treated with a cycle of rhNGF (cenegermin 20 µg/mL) eye drops. Due to the complications of a further NK recurrence after treatment discontinuation, a second AMT and PK approach was chosen. A second cycle of treatment with cenegermin was immediately initiated after PK to prevent further recurrences. No postoperative complications were observed and we report a stable situation at 1 year of follow-up.

Conclusion

The case presented here is, to our knowledge, the first report of a treatment with cenegermin for a NK recurrence after PK and suggests that such early medical approach could be evaluated to prevent postoperative complications.

Matrix Regenerating Agent (RGTA) in a Neurotrophic Corneal Ulcer

Neurotrophic keratopathy is a condition associated with corneal damage and impaired corneal healing. There are no specific treatments available for this disease and current treatments are not associated with improved visual function. Matrix regenerating agents (RGTA) are recent topical agents showing positive results in the treatment of several corneal conditions, including neurotrophic keratopathy.

We report the case of a 73-year-old patient with a neurotrophic ulcer treated with RGTA.

Treatment with RGTA allowed complete corneal healing and a dramatic recovery in visual function in our patient. RGTA solutions are an important and safe therapeutic option for the treatment of selected corneal pathology.

[Recurrent corneal erosion: modern view of the problem]

Recurrent corneal erosion syndrome (RCES) is a common chronic disease associated with repeated episodes of epithelial disruption and is characterized by sudden onset of sharp pain in the eye, usually at night or upon waking, as well as redness, photophobia and lacrimation. The cause of the disease is considered to be impaired adhesion of the epithelial layer to the stroma, which is a consequence of abnormal regeneration of the basement membrane of corneal epithelium. A number of biological factors, including inflammatory mediators and proteinases in high concentrations, contribute to the destruction of the formed adhesion complexes. The basis of RCES diagnosis is characteristic medical history and biomicroscopy. An area of epithelium absence can be detected under direct illumination - more often in paracentral view - mainly in the lower third of the cornea, where an area of loose and irregular epithelium with microcysts or grayish inclusions can be seen. There may also be a card-like or «fingerprint» pattern. First of all, it is necessary to differentiate RCES from infectious lesions, which require a fundamentally different treatment regimen. It is believed that the first stage of treatment should include lubricants, drugs that promote epithelialization, inhibitors of matrix metalloproteinases and lipases. The «second line» of conservative treatment can include blood derivatives. If conservative therapy is ineffective, it is advised to use phototherapeutic keratectomy (PTK) or perform diamond burr polishing of Bowman's layer. The choice of a method for treating recurrent erosion should be based on the effectiveness of drug therapy, frequency of recurrence, duration of the disease, severity of clinical symptoms, availability of specific ophthalmic equipment and experience with it.

[Neurotization of the cornea as pathogenically targeted method of treating neurotrophic keratitis in patients with facial paralysis]

Combined lesions of the facial and trigeminal cranial nerves are typical after neurosurgical treatment. Violation of the innervation of orbicularis muscle leads to inability to completely close the eyelids, while denervation of the cornea is often manifested as a long-term ongoing and recurring neurotrophic keratitis. The restoration of corneal innervation is a pathogenetically targeted treatment for this pathology. For this purpose, neurotrophic keratitis could be reversed via the method of corneal neurotization using contralateral n. ophthalmicus. The presented clinical case demonstrates the results of the first operation of neurotization of the cornea in a patient with combined lesions of the facial and trigeminal nerves.

Diabetic keratopathy: Insights and challenges

Ocular complications from diabetes mellitus are common. Diabetic keratopathy, the most frequent clinical condition affecting the human cornea, is a potentially sight-threatening condition caused mostly by epithelial disturbances that are of clinical and research attention because of their severity. Diabetic keratopathy exhibits several clinical manifestations, including persistent corneal epithelial erosion, superficial punctate keratopathy, delayed epithelial regeneration, and decreased corneal sensitivity, that may lead to compromised visual acuity or permanent vision loss. The limited amount of clinical studies makes it difficult to fully understand the pathobiology of diabetic keratopathy. Effective therapeutic approaches are elusive. We summarize the clinical manifestations of diabetic keratopathy and discuss available treatments and up-to-date research studies in an attempt to provide a thorough overview of the disorder.

Long-term restoration of corneal sensitivity in neurotrophic keratopathy after rhNGF treatment

BACKGROUND

To report the long-term effects of the new rhNGF treatment on corneal sensitivity in patients with.

CASES PRESENTATION

We present three cases of corneal ulcers due to NK that were treated with rhNGF. In each patient wound healing evolution was documented by clinical pictures and corneal sensitivity measured by Cochet-Bonnet aesthesiometry. Best corrected visual acuity and Type I Schirmer test were also assessed neurotrophic keratopathy.All patients healed within 8 weeks and NK showed no recurrences in the mean follow-up period of 35 weeks. Each subject showed a significant increase of corneal sensitivity and tear secretion, with concomitant improvement in visual acuity.

CONCLUSION

Corneal sensitivity, measured by Cochet-Bonnet aesthesiometer, markedly increased in all eyes. Further studies are warranted to demonstrate a possible mechanism of nerve restoration with rhNGF treatment.

Corneal melt in conjunctival intraepithelial neoplasia

Purpose

Report a case of corneal melt in a patient with conjunctival intraepithelial neoplasia (CIN) treated with topical interferon (IFN) alpha-2B.

Observations

An 89-year-old man presented with gelatinous paralimbal lesions of the left eye extending onto the cornea with corneal neovascularization extending 5–6 clock hours. Nasally there was mild absence of the terminal vascular loops of the limbal palisades of Vogt and conjunctivalization. Diffuse punctate epithelial erosions were noted. The corneal graft displayed subepithelial and stromal edema. Anterior segment optical coherence tomography detected hyperreflectivity, sectional thickened epithelium, and abrupt transitions from normal to abnormal tissue. The patient was treated with excision of the corneal and conjunctival lesions with cryotherapy to the conjunctival borders. Excisional biopsy revealed CIN Grade 3 and carcinoma in situ of the cornea. Topical IFN alpha-2B four times daily was initiated postoperatively. Two months later, a central epithelial defect developed. The cornea progressively thinned and corneal melt ensued. The patient had several risk factors for corneal melt including neurotrophic cornea, early limbal stem cell deficiency, history of cryotherapy, keratoconjunctivitis sicca, and chronic use of glaucoma medications and steroid medications.

Conclusions

Interferon alpha-2B is an effective first line treatment for CIN with few side effects. It's side effects include punctate epithelial erosions, conjunctival hyperemia, and follicular conjunctivitis. We report a case of pre-existing keratoconjunctivitis sicca, early limbal stem cell deficiency, neurotrophic cornea, and newly diagnosed CIN Grade 3; it was treated with surgical excision, cryotherapy, and topical IFN alpha-2b with development of corneal melt 2 months later. Caution should be taken when using interferon alpha -2b in patients with pre-existing keratoconjunctivitis sicca, neurotrophic cornea, or limbal stem cell deficiency as it could exacerbate these conditions resulting in corneal melt.

Implications of NAD+ Metabolism in the Aging Retina and Retinal Degeneration

Nicotinamide adenine dinucleotide (NAD⁺) plays an important role in various key biological processes including energy metabolism, DNA repair, and gene expression. Accumulating clinical and experimental evidence highlights an age-dependent decline in NAD⁺ levels and its association with the development and progression of several age-related diseases. This supports the establishment of NAD⁺ as a critical regulator of aging and longevity and, relatedly, a promising therapeutic target to counter adverse events associated with the normal process of aging and/or the development and progression of age-related disease. Relative to the above, the metabolism of NAD⁺ has been the subject of numerous investigations in various cells, tissues, and organ systems; however, interestingly, studies of NAD⁺ metabolism in the retina and its relevance to the regulation of visual health and function are comparatively few. This is surprising given the critical causative impact of mitochondrial oxidative damage and bioenergetic crises on the development and progression of degenerative disease of the retina. Hence, the role of NAD⁺ in this tissue, normally and aging and/or disease, should not be ignored. Herein, we discuss important findings in the field of NAD⁺ metabolism, with particular emphasis on the importance of the NAD⁺ biosynthesizing enzyme NAMPT, the related metabolism of NAD⁺ in the retina, and the consequences of NAMPT and NAD⁺ deficiency or depletion in this tissue in aging and disease. We discuss also the implications of potential therapeutic strategies that augment NAD⁺ levels on the preservation of retinal health and function in the above conditions. The overarching goal of this review is to emphasize the importance of NAD⁺ metabolism in normal, aging, and/or diseased retina and, by so doing, highlight the necessity of additional clinical studies dedicated to evaluating the therapeutic utility of strategies that enhance NAD⁺ levels in improving vision.

Development of the neurotrophic keratopathy questionnaire: qualitative research

BACKGROUND

Neurotrophic keratopathy/keratitis (NK) is a rare disease of the cornea that can lead to anatomical loss of the eye. Little is known about the NK experience from the patients' perspective. The objectives of this study were to examine the symptomatic experience and impacts of NK on patients and assess the overall comprehension, relevance, and content validity of a new questionnaire.

METHODS

This was a cross-sectional, qualitative study conducted with NK patients with varying levels of disease severity, recruited from one clinical site. One-on-one interviews using concept elicitation and cognitive interviewing techniques were conducted.

RESULTS

Fourteen NK patients participated; 64.3% were female (n = 9), mean age was 65.7 ± 13.3, and 14.3% (n = 2), 21.4% (n = 3), and 64.3% (n = 9) were classified as Mackie stage I, stage II, or stage III, respectively. Participants reported 24 concepts, including: redness (n = 12, 86%), sensitivity to light (n = 11, 79%), general discomfort (n = 9, 64%), dry eye (n = 9, 64%), reduced visual acuity (n = 9, 64%), blurred vision (n = 8, 57%), and eye fatigue (n = 8, 57%). No new concepts were reported after the 13th interview. The most frequently reported impacts included frustration (n = 10, 71%), driving impairment (n = 8, 57%), reading impairment (n = 7, 50%), difficulty watching television (n = 7, 50%), and concern with potentially losing their eyesight due to NK (n = 6, 43%). Participants provided positive feedback on the draft NK Questionnaire (NKQ) and felt that it was comprehensive and relevant to their experience with NK. Additionally, the recall period, instructions, item concepts, and response options were well-understood by participants. Minor revisions were made to the tool for consistency (i.e., the timeframe "in the past 7 days" was added to items 12-14); item 14 was modified to include "how often"; examples were added to item 9.

CONCLUSIONS

The results of the concept elicitation portion of the qualitative study support the content validity of the draft NKQ. The clinically significant concepts identified in the literature and raised during concept elicitation are included as items in the questionnaire. Further assessment of the psychometric properties should be conducted in support of this new tool to measure the effect of new treatments on symptoms and impacts associated with NK.

Topical Pergolide Enhance Corneal Nerve Regrowth Following Induced Corneal Abrasion

Purpose

Neurotrophic keratopathy is a degenerative disease that may be improved by nerve growth factor (NGF). Our aim was to investigate the use of pergolide, a dopamine (D1 and D2) receptor agonist known to increase the synthesis and release of NGF for regeneration of damaged corneal nerve fibers.

Methods

Pergolide function was evaluated by measuring axon length and NGF levels by enzyme-linked immunosorbent assay in cultured chicken dorsal root ganglion (DRG) cells with serial doses of pergolide (10, 25, 50, 150, and 300 µg/ml) and with different concentrations of a D1 antagonist. Pergolide function was further evaluated by cornea nerve fiber density and wound healing in a cornea scratch mouse model.

Results

Pergolide increased DRG axon length significantly at a dose between 50 and 300 µg/ml. Different concentrations of D1 antagonist (12, 24, 48, and 96 µg/ml) inhibited DRG axon length growth with pergolide (300 µg/ml). Pergolide (50 µg/ml) upregulated NGF expression in DRG cells at both 24 hours and 48 hours. Pergolide improved cornea nerve fiber density at both 1 week and 2 weeks. Pergolide also improved cornea wound healing.

Conclusions

We demonstrated that pergolide can act to promote an increase in NGF which promotes corneal nerve regeneration and would therefore improve corneal sensation and visual acuity in eyes with peripheral neurotrophic keratopathy.

The supraorbital and supratrochlear nerves for ipsilateral corneal neurotization: anatomical study

Neurotrophic keratitis is a rare corneal disease that is challenging to treat. Corneal neurotization (CN) is among the developing treatments that uses the supraorbital (SON) or supratrochlear (STN) nerve as a donor. Therefore, the goal of this study was to provide the detailed anatomy of these nerves and clarify their feasibility as donors for ipsilateral CN. Both sides of 10 fresh-frozen cadavers were used in this study, and the SON and STN were dissected using a microscope intra- and extraorbitally. The topographic data between the exit points of these nerves and the medial and lateral angle of the orbit were measured, and nerve rotation of these nerves toward the ipsilateral cornea were attempted. The SON and STN were found on 19 of 20 sides. The vertical and horizontal distances between the exit point of the SON and that of the STN, were 7.3±2.1 mm (vertical) and 4.5±2.3 mm, respectively. The mean linear distances between the medial angle and the exit points of each were 22.2±3.0 mm and 14.5±1.9 mm, respectively, and the mean linear distances between the lateral angle and the exit points of the SON and STN were 34.0±2.7 mm and 36.9±2.5 mm, respectively. These nerves rotated ipsilaterally toward the center of the orbit easily. A better understanding of the anatomy of these nerves can contribute to the development and improvement of ipsilateral CN.

Cenegermin for Treating Neurotrophic Keratitis: An Evidence Review Group Perspective of a NICE Single Technology Appraisal

As part of the Single Technology Appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the manufacturer of cenegermin (OXERVATE^®, Dompé) to submit evidence for the clinical and cost effectiveness of cenegermin for neurotrophic keratitis (NK). The Liverpool Reviews and Implementation Group (LRiG) at the University of Liverpool was commissioned to act as the Evidence Review Group (ERG). This article summarises the ERG's review of the evidence submitted by the company and provides a summary of the Appraisal Committee's (AC) final decision. Clinical-effectiveness evidence from two phase II randomised controlled trials (RCTs) of cenegermin found cenegermin to improve corneal healing after 8 weeks compared with vehicle, considered a proxy for artificial tears. Longer-term data and comparisons with other relevant comparators were insufficient to draw conclusions. The company developed a de novo economic model that found cenegermin to be dominant when compared with artificial tears, except in one of seven scenarios. However, the ERG considered that the model had a major structural flaw in that it failed to allow patients to enter a 'sustained healing' state from 'standard of care (SoC) non-healing' and 'SoC deteriorating' states, or to move into an 'SoC deteriorating' state from an 'SoC non-healing' state. Following the first AC meeting, the company submitted a revised model with a revised model structure that removed the 'SoC deteriorating' state and introduced an 'SoC healed' state to sit alongside the existing 'sustained healing' and 'SoC non-healing' states from the original model. However, the ERG continued to express concerns, which included (1) extrapolation of the treatment effect of cenegermin over a patient's lifetime; (2) the assumption that patients had two specialist visits a month; (3) the assumption that artificial tears, autologous serum eye drops and contact lenses continued for a lifetime after healing; (4) the simplified modelling of costs and utilities; and (5) the underlying uncertainty in the utility values. The ERG therefore considered the company's model could not produce a robust incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained. The ERG did however present an alternative ICER by amending the use and cost of autologous serum eye drops, contact lenses and artificial tears in the 'healed' and 'non-healed' states. Applying these changes produced an ICER of £302,717 per QALY gained. Because of uncertainties with the clinical- and cost-effectiveness evidence, the AC concluded that cenegermin cannot be recommended within its marketing authorisation for NK.

Promising Approach in the Treatment of Glaucoma Using Nanotechnology and Nanomedicine-Based Systems

Glaucoma is considered a leading cause of blindness with the human eye being one of the body's most delicate organs. Ocular diseases encompass diverse diseases affecting the anterior and posterior ocular sections, respectively. The human eye's peculiar and exclusive anatomy and physiology continue to pose a significant obstacle to researchers and pharmacologists in the provision of efficient drug delivery. Though several traditional invasive and noninvasive eye therapies exist, including implants, eye drops, and injections, there are still significant complications that arise which may either be their low bioavailability or the grave ocular adverse effects experienced thereafter. On the other hand, new nanoscience technology and nanotechnology serve as a novel approach in ocular disease treatment. In order to interact specifically with ocular tissues and overcome ocular challenges, numerous active molecules have been modified to react with nanocarriers. In the general population of glaucoma patients, disease growth and advancement cannot be contained by decreasing intraocular pressure (IOP), hence a spiking in future research for novel drug delivery systems and target therapeutics. This review focuses on nanotechnology and its therapeutic and diagnostic prospects in ophthalmology, specifically glaucoma. Nanotechnology and nanomedicine history, the human eye anatomy, research frontiers in nanomedicine and nanotechnology, its imaging modal quality, diagnostic and surgical approach, and its possible application in glaucoma will all be further explored below. Particular focus will be on the efficiency and safety of this new therapy and its advances.

Update On Cenegermin Eye Drops In The Treatment Of Neurotrophic Keratitis

Neurotrophic keratitis is an underdiagnosed degenerative condition induced by impairment to the corneal nerves which may lead to persistent epithelial defects and corneal blindness. Current medical and surgical treatments are only supportive and poorly tackle the underlying problem of corneal anesthesia; hence, fail to provide a permanent cure. Cenegermin is a newly introduced recombinant human nerve growth factor (rhNGF) that may address this issue. Preliminary clinical trials have demonstrated the safety and efficacy of topical cenegermin in patients with moderate to severe neurotrophic keratitis; however, the clinical experience with this drug is still limited. This review summarizes the pathogenesis and management of neurotrophic keratitis as well as the mechanism of action, uses, and limitations of cenegermin eye drops in the treatment of neurotrophic keratitis.

Complement and CD4+ T cells drive context-specific corneal sensory neuropathy

Whether complement dysregulation directly contributes to the pathogenesis of peripheral nervous system diseases, including sensory neuropathies, is unclear. We addressed this important question in a mouse model of ocular HSV-1 infection, where sensory nerve damage is a common clinical problem. Through genetic and pharmacologic targeting, we uncovered a central role for C3 in sensory nerve damage at the morphological and functional levels. Interestingly, CD4 T cells were central in facilitating this complement-mediated damage. This same C3/CD4 T cell axis triggered corneal sensory nerve damage in a mouse model of ocular graft-versus-host disease (GVHD). However, this was not the case in a T-dependent allergic eye disease (AED) model, suggesting that this inflammatory neuroimmune pathology is specific to certain disease etiologies. Collectively, these findings uncover a central role for complement in CD4 T cell-dependent corneal nerve damage in multiple disease settings and indicate the possibility for complement-targeted therapeutics to mitigate sensory neuropathies.

[Pathogenesis and epidemiology of neurotrophic keratopathy]

Neurotrophic keratopathy (NK) is a degenerative corneal disease that is based on an impairment of the corneal innervation. The damage to the sensory innervation, which is delivered through the 1st branch of the trigeminal nerve (ophthalmic nerve), can occur throughout the entire length of the nerve from the nucleus in the brainstem, e.g. caused by brain tumors, to the terminal nerve fibers in the cornea, caused for example by refractive corneal surgery (e. g. LASIK). Due to the loss of the sensory innervation, a reduced lacrimation and a reduction in the secretion of trophic factors occur. This in turn inhibits the regeneration potential of the corneal epithelium. In the most severe cases of the disease, the reduction or loss of lacrimation, together with the impaired regeneration potential of the epithelial cells, can lead to persistent epithelial defects, ulcers and corneal perforation. The NK has a prevalence of 5 or fewer individuals per 10,000 and is classified as a rare, i. e. orphan disease (ORPHA137596). A fundamental understanding of the pathogenesis and epidemiology of NK supports the early diagnosis and therefore the initiation of a specific treatment.

Corneal Involvement in Wallenberg Syndrome: Case Report and Literature Review

A 47-year-old man with Wallenberg syndrome after a stroke in the territory of the left vertebrobasilar artery and posterior inferior cerebellar artery, presented a week later complaining of visual loss in the left eye. Examination showed corneal anaesthesia associated with a neurotrophic corneal epithelial defect. Corneal involvement secondary to trigeminal neuropathy in Wallenberg syndrome is not frequently reported and may lead to epithelial erosion and neurotrophic keratopathy. Clinicians should be aware that visual loss can occur from a neurogenic basis (e.g., Wallenberg syndrome) due to neurotrophic keratopathy. The use of cocaine, a potential cause of neurotrophic keratopathy, should also be suspected in the appropriate clinical scenario.

Recurrent corneal erosion: a comprehensive review

Purpose

To comprehensively review the literature regarding recurrent corneal erosion (RCE) and to present treatment options and recommendations for management.

Overview

RCE usually presents with sharp, unilateral pain upon awakening, in an eye with an underlying basement membrane dystrophy, prior ocular trauma, stromal dystrophy or degeneration, or prior surgery for refractive errors, cataracts, or corneal transplantation. Making the correct diagnosis requires a careful slit-lamp examination of both eyes coupled with a high degree of suspicion. Several treatments are commonly used for RCE but new therapies have been introduced recently. Conservative treatment consists of antibiotic and preservative-free lubricating drops, with topical cycloplegics and oral analgesics to control pain. Patients who are unresponsive to these therapies may benefit from therapeutic bandage contact lenses (BCL). Newer therapies include oral matrix metalloproteinase (MMP) inhibitors, blood-derived eye drops, amniotic membrane graft application, and judicious application of topical corticosteroids. Once the epithelium is healed, a course of hypertonic saline solution and/or ointment can be used. Surgical procedures may be performed in patients who fail conservative therapy. Punctal occlusion with plugs increases the tear film volume. Epithelial debridement with diamond burr polishing (DBP), anterior stromal puncture (ASP), or alcohol delamination should be considered in selected patients. DBP can be used for patients with basement membrane dystrophies and is the preferred treatment overall due to a low recurrence rate. ASP can be used for erosions outside the central visual axis. Excimer laser phototherapeutic keratectomy is an attractive option in eyes with central RCE since it precisely removes tissue while preserving corneal transparency. In patients with RCE who are also candidates for refractive surgery, photorefractive keratectomy can be considered.

Summary

Newly introduced therapies for RCE enable therapy to be individualized and lower the recurrence rate.

[Clinical picture and diagnosis of neurotrophic keratopathy]

BACKGROUND

Neurotrophic keratopathy is characterized by corneal surface alterations, persistent corneal epithelial defects and/or corneal ulcerations associated with corneal sensory abnormalities. Due to the variable clinical picture neurotrophic keratopathy is often overlooked or diagnosed too late in the course of the disease.

OBJECTIVE

Discussion of the clinical picture of neurotrophic keratopathy and recommendations for correct diagnosis.

MATERIAL AND METHODS

Analysis of the existing literature and discussion of basic recent publications.

RESULTS

Neurotrophic keratopathy is defined as a disease related to alterations in corneal nerves leading to impairment in sensory and trophic function with consequent breakdown of the corneal epithelium affecting health and integrity of the tear film, epithelium and stroma. It can occur with infections, autoimmune diseases, after trauma or ocular surgery, with intracranial neoplasia, in systemic diseases and genetic syndromes. It is classified into three stages: mild (epithelial changes without epithelial defects), moderate (epithelial defects) and severe (stromal involvement). The clinical hallmark is reduced or absent corneal sensation. Therefore, corneal sensitivity testing is essential in the diagnosis of neurotrophic keratopathy along with the patient history, clinical examination and diagnostic tests, such as vital stains and, if possible, in vivo confocal microscopy.

CONCLUSION

The correct diagnosis and classification of neurotrophic keratopathy enable a stage-adapted step-ladder therapeutic approach with subsequent reduction of progression and complications of the disease.

Sphingomonas paucimobilis keratitis in a patient with neurotrophic keratopathy and severe neurosensory hypoacusis: Treatment with penetrating keratoplasty and amniotic membrane grafting

We describe a case of a man with neurotrophic keratitis of unknown ethiology, who developed a massive stromal melting during treatment of a persistent epithelial defect. A tectonic keratoplasty combined with amniotic membrane grafting was made. Host cornea specimen was analyzed, and Sphingomonas paucimobilis was isolated.

Axon numbers and landmarks of trigeminal donor nerves for corneal neurotization

Purpose

Corneal anesthesia leads to chronic corneal injury. This anatomical study characterizes the donor nerve branches of the supratrochlear and supraorbital nerves used for corneal neurotization.

Methods

In 13 non-embalmed cadavers, the supratrochlear and supraorbital nerves were dissected and distances to anatomical landmarks measured. Cross-sections of supratrochlear and supraorbital donor nerves were harvested and histomorphometrically analyzed to assess the number of myelinated axons.

Results

The donor axon counts were 3146 ± 1069.9 for the supratrochlear and 1882 ± 903 for the supraorbital nerve distal to the supraorbital notch. The supratrochlear nerve was dissected on the medial upper eyelid 2 cm lateral to the facial midline and the branch of the supraorbital nerve 1 cm medial to the mid-pupillary line.

Conclusion

The supraorbital and supratrochlear branches of the trigeminal nerve are potent donor nerves for corneal neurotization in the treatment of neuropathic keratopathy and can be reliably dissected using anatomical landmarks.

Corneal ulcer as the presenting feature of type 2 diabetes mellitus

A 60-year-old woman, with no significant medical or ophthalmic history, presented with a unilateral large corneal ulcer and hypopyon. Despite a severely injected conjunctiva and large corneal epithelial defect, the patient denied any discomfort in the eye. The ulcer was extremely slow to heal requiring prolonged treatment with topical and systemic broad-spectrum antibiotics. Due to the corneal opacification, fundal examination was not possible. Subsequent examination of the fellow eye revealed an appearance consistent with proliferative diabetic retinopathy. She was given treatment with panretinal laser photocoagulation. There was no history of diabetes and the patient denied experiencing any of the classical symptoms of hyperglycaemia. With blood tests revealing a raised plasma glucose and Haemoglobin A1c (HbA1c), a new diagnosis of diabetes mellitus was made. With the commencement of treatment for diabetes, there were signs of improvement in the corneal appearance.

Anatomic characteristics of supraorbital and supratrochlear nerves relevant to their use in corneal neurotization

BACKGROUND

Corneal denervation can lead to opacification and blindness. A new treatment technique, surgical corneal neurotization, transfers healthy donor nerve, (most commonly contralateral supratrochlear or supraorbital) to the affected limbus to prevent corneal destruction and improve healing potential of the cornea following insult. We examine gross and histomorphometric anatomy of the supratrochlear and supraorbital nerves relevant to their use in corneal neurotization.

METHODS

For each of nine adult cadaver heads, bilateral supraorbital and supratrochlear nerves were dissected from the supraorbital rim to the anterior hairline. The following data were recorded for each nerve: exit from the orbit through a notch versus foramen; horizontal distance from midline at the supraorbital rim; and distance from orbital exit to first branching point. Samples of all left supraorbital and supratrochlear nerves were obtained at the level of the supraorbital rim and at points 3 cm and 6 cm distally for histomorphometric analysis. Myelinated axon counts were determined for each sample.

RESULTS

Four supraorbital foramina, 14 supraorbital notches, two supratrochlear foramina, and 15 supratrochlear notches were identified. Average supraorbital and supratrochlear distances to midline were 26.5 mm and 21 mm respectively. Average myelinated axon counts for both nerves were greater at the orbital rim (supraorbital: 6018, supratrochlear: 2533) than at 6 cm distally (supraorbital: 1621, supratrochlear: 1112).

CONCLUSIONS

Anatomic dissection shows relative close approximation of the supraorbital and supratrochlear nerves, with a high proportion of both nerves exiting the orbit through foramina. The supraorbital nerve at the orbital rim contains the greatest number of myelinated axons.

Neurotrophic keratitis: current challenges and future prospects

Neurotrophic keratitis (NK) is a degenerative corneal disease caused by damage of trigeminal corneal innervation, which leads to spontaneous epithelial breakdown and corneal ulceration. The impairment of corneal sensory innervation causes the reduction of both protective reflexes and trophic neuromodulators that are essential for the vitality, metabolism, and wound healing of ocular surface tissues. A wide range of ocular and systemic conditions, including herpetic keratitis, ocular chemical burns, corneal surgery, diabetes, multiple sclerosis, and neurosurgical procedures, can cause NK by damaging trigeminal innervation. Diagnosis of NK requires careful investigation of any ocular and systemic condition associated with the disease, complete ocular surface examination, and quantitative measurement of corneal sensitivity. The clinical stages of NK range from corneal epithelial alterations (stage 1) to persistent epithelial defect (stage 2) and ulcer (stage 3), which may progress to corneal perforation. Management of NK is based on clinical severity, and the aim of the therapy is to halt the progression of corneal damage and promote epithelial healing. Although several medical and surgical treatments have been proposed, no therapies are currently available to restore corneal sensitivity, and thus, NK remains difficult and challenging to treat. The purpose of this review is to summarize available evidence on the pathogenesis, diagnosis, and treatment of NK. Novel medical and surgical therapies including the topical administration of nerve growth factor and corneal neurotization are also described.

Clinical Efficacy of Platelet-Rich Plasma in the Treatment of Neurotrophic Corneal Ulcer

Purpose

Platelet-rich plasma (PRP) is an autologous blood product without preservatives and rich in proteins and growth factors which make it possible for cells to differentiate, proliferate, and migrate, thus stimulating healing and regeneration of tissues. The aim of this study was to evaluate the efficiency of autologous platelet-rich plasma in the treatment of neurotrophic keratopathy.

Methods

The study group consists of 25 patients with nonhealing corneal ulcers due to herpes simplex or herpes zoster infection and facial nerve or trigeminal nerve paralysis as a result of a neurosurgical operation caused by a tumour or stroke. The patients were given autologous platelet-rich plasma drops five times a day and additionally preservative-free artificial tears and a vitamin A ointment at night for maximum 3 months. The following were evaluated: best corrected visual acuity (BCVA), healing of corneal surface, subjective symptoms, and changes in corneal thickness with the use of anterior segment optical coherent tomography (AS-OCT).

Results

BCVA before the treatment was 0.10 ± 0.14, and after the treatment it was –0.3 ± 0.27 (p=0.001). Improved visual acuity and less subjective symptoms were observed in all patients. Complete healing of the ulceration was observed in 20 patients (80%). Four patients (16%) experienced considerable improvement of their clinical condition (reduced size and depth of the ulceration and inflammatory state: smaller conjunctival injection and swelling, improved visual acuity, and less subjective symptoms). In one of the patients, an amniotic membrane was transplanted due to the lack of improvement of his local condition. In all patients, the progression of corneal thinning was stopped. An average corneal thickness in its thinnest point was 322.3 ± 125.8 µm before the treatment, and 404.5 ± 118.7 µm (p < 0.05) after the treatment. None of the patients reported general or local side effects of the treatment.

Conclusions

Autologous platelet-rich plasma is a blood-based product which seems efficient in the treatment of neurotrophic keratopathy.

Neurotrophic Keratopathy after Trigeminal Nerve Block for Treatment of Postherpetic Neuralgia

Purpose

To report a case of persistent corneal epithelial defect that had occurred after a trigeminal nerve block.

Case Presentation

A 75-year-old female had suffered from postherpetic neuralgia for 8 years. She underwent Gasserian ganglion block surgery and noticed declining visual acuity in the right eye on the following day. She presented with severe hyperemia and corneal epithelial defects in the right eye and experienced remarkable reduction of sensitivity in the right cornea. She was diagnosed with neurotrophic keratopathy. Ofloxacin eye ointment and rebamipide ophthalmic suspension ameliorated the corneal epithelial defects but superficial punctate keratopathy, corneal superficial neovascularization, and Descemet's fold persisted. Although the epithelial defects occasionally recurred, the corneal sensation and epithelial defects, Descemet's fold, and corneal superficial neovascularization all improved around 5 months after trigeminal nerve block. The HRT II Rostock Cornea Module (RCM) could not detect any corneal subbasal nerve fibers at postoperative 4 months; however, it could detect them at postoperative 6 months.

Conclusions

As the nerve block effect wore off, the corneal subbasal nerve fibers slowly regenerated. As the corneal sensation improved, the corneal epithelial defects and superficial neovascularization also improved. The HRT II RCM appeared useful for observing loss and regeneration of the corneal subbasal nerve fibers.

Diabetic corneal neuropathy: clinical perspectives

Diabetic keratopathy is characterized by impaired innervation of the cornea that leads to decreased sensitivity, with resultant difficulties with epithelial wound healing. These difficulties in wound healing put patients at risk for ocular complications such as surface irregularities, corneal infections, and stromal opacification. Pathological changes in corneal innervations in diabetic patients are an important early indicator of diabetic neuropathy. The decrease in corneal sensitivity is strongly correlated with the duration of diabetes as well as the severity of the neuropathy. This review presents recent findings in assessing the ocular surface as well as the recent therapeutic strategies for optimal management of individuals with diabetes who are susceptible to developing diabetic neuropathy.

Vitamin B12 Deficiency as a Cause of Neurotrophic Keratopathy

Introduction:

Neurotrophic keratitis is a rare degenerative corneal disease caused by an impairment of trigeminal corneal innervation, leading to a decrease or absence of corneal sensation. Here, we present a case of neurotrophic keratopathy caused by B12 deficiency in a 34 years old man who had a progressive decrease in visual acuity and corneal involvement since 3 months before being referred to our ophthalmology clinic.

Result and Discussion:

Based on our clinical findings and with the diagnosis of B12 deficiency we started B12 treatment for the patient. After 3 weeks the patient showed a dramatic response with corneal sensation reversal, an increase of visual acuity, improved neurotrophic keratopathy and significantly improved neurological findings. To the best of our knowledge, there is no report regarding vitamin B12 deficiency induced keratopathy and this is the first report that describes this aspect of vitamin B12 deficiency.

A Case of Neurotrophic Keratopathy Concomitant to Brain Metastasis

We report a case of a 63-year-old Caucasian female referred to the cornea service of Clinica Oculistica with a neurotrophic corneal ulcer, decreased corneal sensitivity, absent corneal reflex, and decreased lacrimation. The medical record review was relevant for mastectomy and adjuvant therapy for breast cancer complicated by pontocerebellar angle metastasis. Eye patching and application of antibiotic and vitamin ointments were prescribed at first, without a significant improvement. Thus, treatment with autologous serum was started. In about two weeks, the cornea recovered and visual acuity improved with a residual corneal scarring. Finally, we should mention that, in our case, the main cause of the neurotrophic corneal ulcer could be identified in the previous trigeminal damage at the pontocerebellar angle and trigeminal ganglion. Sensory nerves play an important regulatory role via neuro-mediators on corneal wound healing, as denervation may interfere with cellular metabolism and inhibit mitosis, leading to an epithelial defect even with no direct damage.

Corneal nerve regeneration after herpes simplex keratitis: A longitudinal in vivo confocal microscopy study

PURPOSE

To evaluate the long-term alterations of corneal nerves in patients with herpes simplex virus (HSV) keratitis using in vivo confocal microscopy (IVCM).

DESIGN

Prospective, longitudinal, cross sectional.

METHODS

This study included 16 patients with a history of HSV keratitis and 15 age-matched normal controls. Slit-scanning IVCM was performed in all subjects at baseline and then after a mean follow-up of 37.3 ± 1.7 months in the patient group. Corneal subbasal nerve density and corneal sensation were compared between groups at baseline and follow-up.

RESULTS

At baseline, the mean subbasal nerve density was significantly lower in both affected eyes (1.4 ± 0.6 mm/mm²) and contralateral unaffected eyes (6.4 ± 0.7 mm/mm²) compared with the controls (14.1 ± 1.6 mm/mm²; all P < .001). At the end of follow-up, the mean nerve density in affected eyes increased to 2.8 ± 0.7 mm/mm² (P = .006), with no significant change in contralateral unaffected eyes (6.5 ± 1.0 mm/mm², P = .72). However, both eyes had lower nerve density than controls (all P < .001). Corneal sensation was significantly lower in affected eyes (2.6 ± 0.6 cm) than in the control group (6.0 ± 0.0, P < .001) and showed no significant change at the end of follow-up (2.5 ± 0.6 cm, P = .80). Corneal sensation in contralateral unaffected eyes was not different in comparison with controls at both baseline and follow up (all p > .05).

CONCLUSIONS

Our results demonstrate that although corneal nerve regeneration occurs in patients with HSV keratitis, this change is not clinically significant and does not results in changes of corneal sensation. Therefore, these patients need to be followed closely for complications of neurotrophic keratopathy and might benefit from neuro-regenerative therapies.

Goldenhar syndrome: current perspectives

BACKGROUND

Progress in medical branches that has taken place since the first child with Goldenhare syndrome (GS) had been described in 1952 by Maurice Goldenhar, facilitated better understanding of this congenital defect. It also gave new perspectives and the opportunity to achieve satisfactory treatment results, mainly due to development of surgical techniques.

DATA SOURCES

Based on the literature and own experience, we discussed the phenotype of presentation of GS, ethiopathogenesis, genetic counselling and treatment with particular emphasis on surgery correction of hemifacial microsomia.

RESULTS

The spectrum of GS abnormalities ranges from mild to severe ones and include patients with barely noticeable facial asymmetry to very pronounced facial defect with more or less severe abnormalities of internal organs and/or skeleton. It is characterized most commonly by impaired development of eyes, ears, lips, tongue, palate, mandible, maxilla, zygomatic and orbital structures and deformations of the teeth structures. Ethiopathogenesis is multifactorial and dependent on genetic and environmental factors but there are still many unknowns about the syndrome which should be revealed.

CONCLUSIONS

Patients with GS due to a large variety of abnormalities and different severity of symptoms pose a challenge for clinicians. All of this necessitate an individual approach to each single patient and involvement a team of specialists in treatment planning. It is a complex, long-lasting, multidisciplinary process and should be divided into stages, according to patient's age, as well as the extent and severity of observed abnormalities. Neonatologists and pediatricians are involved in care of these patients from the onset.

Asymptomatic Corneal Keratopathy Secondary to Hypertyrosinaemia Following Low Dose Nitisinone and a Literature Review of Tyrosine Keratopathy in Alkaptonuria

Nitisinone, although unapproved for use in alkaptonuria (AKU), is currently the only homogentisic acid lowering therapy with a potential to modify disease progression in AKU. Therefore, safe use of nitisinone off-label requires identifying and managing tyrosine keratopathy. A 22-year-old male with AKU commenced 2 mg daily nitisinone after full assessment. He was issued an alert card explaining potential ocular symptoms such as red eye, tearing, ocular pain and visual impairment and how to manage them. On his first and second annual follow-up visits to the National Alkaptonuria Centre (NAC), there was no corneal keratopathy on slit lamp examination. On his third follow-up annual visit to the NAC, he was found to have typical dendritiform corneal keratopathy in both eyes which was asymptomatic. Nitisinone was suspended until a repeat slit lamp examination, 2 weeks later, confirmed that the keratopathy had resolved. He recommenced nitisinone 2 mg daily with a stricter low protein diet. On his fourth annual follow-up visit to the NAC, a routine slit lamp examination showed mild corneal keratopathy in the left eye. This is despite him reporting no ocular symptoms. This case highlights the fact that corneal keratopathy can occur without symptoms and any monitoring plan with off-label use of nitisinone in AKU will need to take this possibility into account. This is also the first time that typical corneal keratopathy has been described with the use of low dose nitisinone in AKU without symptoms.

Colony Stimulating Factor-1 Receptor Expressing Cells Infiltrating the Cornea Control Corneal Nerve Degeneration in Response to HSV-1 Infection

Purpose

Herpes simplex virus type-1 (HSV-1) is a leading cause of neurotrophic keratitis, characterized by decreased or absent corneal sensation due to damage to the sensory corneal innervation. We previously reported the elicited immune response to infection contributes to the mechanism of corneal nerve regression/damage during acute HSV-1 infection. Our aim is to further establish the involvement of infiltrated macrophages in the mechanism of nerve loss upon infection.

Methods

Macrophage Fas-Induced Apoptosis (MAFIA) transgenic C57BL/6 mice were systemically treated with AP20187 dimerizer or vehicle (VEH), and their corneas, lymph nodes, and blood were assessed for CD45+CD11b+GFP+ cell depletion by flow cytometry (FC). Mice were ocularly infected with HSV-1 or left uninfected. At 2, 4, and/or 6 days post infection (PI), corneas were assessed for sensitivity and harvested for FC, nerve structure by immunohistochemistry, viral content by plaque assay, soluble factor content by suspension array, and activation of signaling pathways by Western blot analysis. C57BL6 mice were used to compare to the MAFIA mouse model.

Results

MAFIA mice treated with AP20187 had efficient depletion of CD45+CD11b+GFP+ cells in the tissues analyzed. The reduction of CD45+CD11b+GFP+ cells recruited to the infected corneas of AP20187-treated mice correlated with preservation of corneal nerve structure and function, decreased protein concentration of inflammatory cytokines, and decreased STAT3 activation despite no changes in viral content in the cornea compared to VEH-treated animals.

Conclusions

Our results suggest infiltrated macrophages are early effectors in the nerve regression following HSV-1 infection. We propose the neurodegeneration mechanism involves macrophages, local up-regulation of IL-6, and activation of STAT3.

Unravelling the stromal-nerve interactions in the human diabetic cornea

Corneal defects due to diabetes mellitus (DM) may cause severe vision impairments. Current studies focus on the corneal epithelium and nerve defects neglecting the corneal stroma. The aim of this study was to develop a 3D in vitro model to examine the interactions between corneal stroma and nerves in the context of DM. Primary human corneal stromal fibroblasts isolated from healthy (HCFs), Type 1 (T1DM) and Type 2 (T2DM) patients were stimulated with stable ascorbic acid to secrete and assemble an extracellular matrix (ECM). Human neuronal cells were then seeded on top and differentiated to create the 3D co-cultures. Our data revealed successful co-culture of stromal fibroblasts and neuronal cells with large elongated neuron extensions. T2DM showed significant upregulation of Collagen III and IGF1 when compared to T1DM. Interestingly, upon nerve addition, those markers returned to HCF levels. Neuronal markers were also differentially modulated with T2DM co-cultures expressing high levels of βIII tubulin where T1DM co-cultures expressed Substance P. . Overall, our unique 3D co-culture model provides us with a tool that can be utilized for both molecular and therapeutic studies for diabetic keratopathy.

Long-term consequences of topical dexamethasone treatment during acute corneal HSV-1 infection on the immune system

Herpes simplex virus type 1 (HSV-1) is a leading cause of neurotrophic keratitis (NTK). NTK is characterized by decreased corneal sensation from damage to the corneal sensory fibers. We have reported on the regression of corneal nerves and their function during acute HSV-1 infection. That nerve loss is followed by an aberrant process of nerve regeneration during the latent phase of infection that lacks functional recovery. We recently showed the elicited immune response in the infected cornea, and not viral replication itself, is part of the mechanism responsible for the nerve degeneration process after infection. Specifically, we showed infected corneas topically treated with dexamethasone (DEX) significantly retained both structure and sensitivity of the corneal nerve network in comparison to mice treated with control eye drops, consistent with decreased levels of proinflammatory cytokines and reduced influx of macrophages and CD8+ T cells into the cornea. This study was undertaken to analyze the long-term effect of such a localized, immunosuppressive paradigm (DEX drops on the cornea surface during the first 8 d of HSV-1 infection) on the immune system and on corneal pathology. We found the profound immunosuppressive effect of DEX on lymphoid tissue was sustained in surviving mice for up to 30 d postinfection (p.i.). DEX treatment had prolonged effects, preserving corneal innervation and its function and blunting neovascularization, as analyzed at 30 d p.i. Our data support previously reported observations of an association between the persistent presence of inflammatory components in the latently infected cornea and structural and functional nerve defects in NTK.

Red Eye: A Guide for Non-specialists

BACKGROUND

Red eye can arise as a manifestation of many different systemic and ophthalmological diseases. The physician whom the patient first consults for this problem is often not an ophthalmologist. A correct assessment of the urgency of the situation is vitally important for the planning of further diagnostic evaluation and treatment.

METHODS

This review is based on pertinent publications retrieved by a selective literature search in PubMed in August 2016 as well as on the authors' own clinical and scientific experience.

RESULTS

Primary care physicians typically see 4-10 patients per week who complain of ocular symptoms. Most of them have red eye as the major clinical finding. A detailed history, baseline ophthalmological tests, and accompanying manifestations can narrow down the differential diagnosis. The duration and laterality of symptoms (uni- vs. bilateral) and the intensity of pain are the main criteria allowing the differentiation of non-critical changes that can be cared for by a general practitioner from diseases calling for elective referral to an ophthalmologist and eye emergencies requiring urgent ophthalmic surgery.

CONCLUSION

The differential diagnosis of red eye can be narrowed down rapidly with simple baseline tests and targeted questioning. Patients with ocular emergencies should be referred to an ophthalmologist at once, as should all patients whose diagnosis is in doubt.