Involvement of ocular surface in graft-versus-host disease: An update from immunopathogenesis to treatment.

Graft-versus-host disease is a common complication of hematopoietic stem cell transplantation and the ocular surface is a main target of inflammatory reaction.

Understanding Drivers of Ocular Fibrosis: Current and Future Therapeutic Perspectives.

Ocular fibrosis leads to severe visual impairment and blindness worldwide, being a major area of unmet need in ophthalmology and medicine. To date, the only available treatments are antimetabolite drugs that have significant potentially blinding side effects, such as tissue damage and infection. There is thus an urgent need to identify novel targets to prevent/treat scarring and postsurgical fibrosis in the eye. In this review, the latest progress in biological mechanisms underlying ocular fibrosis are discussed. We also summarize the current knowledge on preclinical studies based on viral and non-viral gene therapy, as well as chemical inhibitors, for targeting TGFß or downstream effectors in fibrotic disorders of the eye. Moreover, the role of angiogenetic and biomechanical factors in ocular fibrosis is discussed, focusing on related preclinical treatment approaches. Moreover, we describe available evidence on clinical studies investigating the use of therapies targeting TGFß-dependent pathways, angiogenetic factors, and biomechanical factors, alone or in combination with other strategies, in ocular tissue fibrosis. Finally, the recent progress in cell-based therapies for treating fibrotic eye disorders is discussed. The increasing knowledge of these disorders in the eye and the promising results from testing of novel targeted therapies could offer viable perspectives for translation into clinical use.

VEGF inhibition alters neurotrophin signalling pathways and induces caspase-3 activation and autophagy in rabbit retina.

This study sought to evaluate the prospective role exerted by vascular endothelial growth factor (VEGF) in the modulation of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) signalling pathways in the rabbit retina. To reach this aim, the anti-VEGF agents aflibercept and ranibizumab were used as a pharmacological approach to evaluate the putative consequences elicited by VEGF inhibition on neurotrophin signalling. VEGF inhibition determined a marked imbalance in proneurotrophin expression, a significant reduction in TrkA and TrkB phosphorylation states and a decrease in the pan-neurotrophin receptor p75. Importantly, VEGF blockade also caused a strong increase in cleaved caspase-3, beclin-1 and lipidated LC3. The effects were more pronounced in the aflibercept group when compared with ranibizumab-treated rabbits, particularly 1 week after injection. This study demonstrates that VEGF exerts pivotal physiological roles in regulating NGF and BDNF pathways in the retina, as its inhibition by anti-VEGF agents deeply impacts neurotrophin homeostasis. These events are accompanied by a sustained induction of apoptotic and autophagic markers, suggesting that anti-VEGF-dependent impairments in neurotrophin signalling could be responsible for the activation of retinal cell death pathways.

Analysis of the Pathogenic Factors and Management of Dry Eye in Ocular Surface Disorders.

The tear film represents the interface between the eye and the environment. The alteration of the delicate balance that regulates the secretion and distribution of the tear film determines the dry eye (DE) syndrome. Despite having a multifactorial origin, the main risk factors are female gender and advanced age. Likewise, morphological changes in several glands and in the chemical composition of their secretions, such as proteins, mucins, lipidics, aqueous tears, and salinity, are highly relevant factors that maintain a steady ocular surface. Another key factor of recurrence and onset of the disease is the presence of local and/or systemic inflammation that involves the ocular surface. DE syndrome is one of the most commonly encountered diseases in clinical practice, and many other causes related to daily life and the increase in average life expectancy will contribute to its onset. This review will consider the disorders of the ocular surface that give rise to such a widespread pathology. At the end, the most recent therapeutic options for the management of DE will be briefly discussed according to the specific underlying pathology.

Age and diabetes related changes of the retinal capillaries: An ultrastructural and immunohistochemical study.

Normal human aging and diabetes are associated with a gradual decrease of cerebral flow in the brain with changes in vascular architecture. Thickening of the capillary basement membrane and microvascular fibrosis are evident in the central nervous system of elderly and diabetic patients. Current findings assign a primary role to endothelial dysfunction as a cause of basement membrane (BM) thickening, while retinal alterations are considered to be a secondary cause of either ischemia or exudation. The aim of this study was to reveal any initial retinal alterations and variations in the BM of retinal capillaries during diabetes and aging as compared to healthy controls. Moreover, we investigated the potential role of vascular endothelial growth factor (VEGF) and pro-inflammatory cytokines in diabetic retina.Transmission electron microscopy (TEM) was performed on 46 enucleated human eyes with particular attention to alterations of the retinal capillary wall and Müller glial cells. Inflammatory cytokines expression in the retina was investigated by immunohistochemistry.Our electron microscopy findings demonstrated that thickening of the BM begins primarily at the level of the glial side of the retina during aging and diabetes. The Müller cells showed numerous cytoplasmic endosomes and highly electron-dense lysosomes which surrounded the retinal capillaries. Our study is the first to present morphological evidence that Müller cells start to deposit excessive BM material in retinal capillaries during aging and diabetes. Our results confirm the induction of pro-inflammatory cytokines TNF-α and IL-1ß within the retina as a result of diabetes.These observations strongly suggest that inflammatory cytokines and changes in the metabolism of Müller glial cells rather than changes in of endothelial cells may play a primary role in the alteration of retinal capillaries BM during aging and diabetes.

Platelet-Rich Plasma (PRP) to promote corneal healing in firework-related ocular burn and total limbal stem cell deficiency (LSCD).

PURPOSE: To report the case of persistent corneal epithelial defect in total limbal stem cell deficiency (LSCD) after severe firework-related ocular burn treated with autologous Platelet-Rich Plasma (PRP). CASE DESCRIPTION: A young patient, victim of fireworks trauma, presented with a large persistent epithelial defect affecting the central cornea of his left eye and progressing to stromal melting, in the context of grade VI ocular surface burn with 12 h limbal involvement. Impression cytology to the cornea confirmed a complete LSCD. Assessment of corneal sensitivity by Cochet Bonnet esthesiometer revealed complete corneal anesthesia. Based on progressive clinical worsening under conventional therapy, the patient was started on very pure autologous PRP eye drops obtained using the Hy-Tissue PRP® technology. Six times a day eye drops administration for 30 days was scheduled in the affected eye. At the end of treatment, the epithelial defect had disappeared being replaced by advancing conjunctiva. CONCLUSION: Our findings provide information on management of ocular burns from fireworks, a subject of current interest and concern. Autologous PRP eye drops prepared using the Hy-Tissue PRP® system and administered in the presence of total LSCD and complete corneal anesthesia, prevented corneal stromal melting to progress and allowed the ocular surface epithelial coverage to re-establish. This paved the way for later successful restorative and reconstructive intervention. Also, first description of the Hy-tissue PRP procedure for ophthalmological use is reported.

Autophagy-lysosome pathway alteration in ocular surface manifestations in Fabry disease patients.

BACKGROUND: Fabry disease (FD) is a rare X-linked, lysosomal storage disorder caused by mutations in the alpha-galactosidase gene and characterized by neurological, cutaneous, renal, cardiovascular, cochleo-vestibular and ocular manifestations. The aim of this study is to characterize morphological, functional and autophagy-lysosome pathway alterations of the ocular surface in FD patients. METHODS: Eleven subjects with a diagnosis of FD and fifteen healthy control subjects were examined. All patients underwent ocular surface slit lamp examination, corneal aesthesiometry and in vivo confocal laser-scanning microscopy (CCM). Conjunctival impression cytology was performed in six FD patients and six controls, to assess for expression of two markers of the autophagy-lysosome pathway: the microtubule-associated protein light chain 3 (LC3) and lysosome-associated membrane protein 2 (LAMP2). RESULTS: Cornea verticillata and increased conjunctival vessel tortuosity were detected respectively in 67% and 33% of patients with FD. Compared with healthy subjects, patients affected by FD showed a significant reduction in corneal nerve fiber length, density and nerve branching on CCM and a significantly increased expression of LC3 on conjunctival impression cytology (p < 0.001). No changes were observed in the conjunctival expression of LAMP2 between the two groups. CONCLUSIONS: This study shows that FD is associated with ocular surface alterations including corneal and conjunctival morphology, innervation and vascularization changes. Our data demonstrate an increased expression of LC3 protein in patients with FD, suggesting that alteration of the autophagy-lysosome pathway may play a role in the occurrence of ocular manifestations.

Obstructive sleep apnoea patients vs laryngopharyngeal reflux disease: Non-invasive evaluation with NBI and pepsin detection in tears.

Obstructive sleep apnoea (OSA) and laryngopharyngeal reflux disease (LPR) are two common diseases that lower patients' quality of life. OSA is defined by cyclic events of airflow obstruction that occur during sleep, while LPR is characterized by upper airway inflammatory signs and symptoms due to the return of gastroduodenal gaseous and liquid elements. pH-metry is the gold standard in LPR diagnosis, but considering its invasiveness among other negative traits, questionnaires that catalog symptoms and signs of the disease such as Reflux Symptoms Index (RSI) and Reflux Finding Score (RFS) are preferred. Moreover, LPR can be evaluated by testing the presence of pepsin in tears, and Narrow Band Imaging (NBI) has been introduced for the early diagnosis of larynx oncological disease. This paper aims to test whether LPR is more frequent in OSA patients than in control ones, performing a non-invasive protocol composed of RSI, RFS test (with light vs. NBI techniques), followed by pepsin detection in tears. 68 LPR patients were enrolled in the study (45 with OSA and 23 without OSA). A strong linear relationship between Apnea-Hypopnea Index (AHI) and Oxygen Desaturation Index (ODI) was found, and patients who presented pepsin in tears had higher values of AHI and ODI in comparison to patients without it. Pathological RFS and NBI showed higher values of AHI and ODI in comparison to the control group. Furthermore, pathological RSI showed higher values of AHI and ODI in comparison to the control group. In conclusion, this diagnostic combined non-invasive protocol may be a good method to perform an early diagnosis of LPR.

Understanding Vernal Keratoconjunctivitis: Beyond Allergic Mechanisms.

Vernal keratoconjunctivitis (VKC) is a chronic, recurrent, inflammatory disease of the cornea and conjunctiva mostly affecting boys in prepubertal age. VKC recurrence is characterized by intense symptoms of itching, redness, and photophobia associated with corneal damage, impairment of visual function, and quality of life. The pathogenesis of VKC has not yet been completely understood, and it is still controversial. In fact, VKC is considered an ocular allergic disease due to the involvement of immunoglobulin E, eosinophils, and mast cells, and of a lymphocyte T-helper type 2 reaction. However, approximately half of VKC patients have negative allergological history and testing, suggesting that other pathogenic mechanisms participate in VKC development and severity. Specifically, evidence suggests that genetic, endocrine, neuronal factors and an imbalance of innate immunity are involved in the pathogenesis of VKC. The purpose of this review is to summarize evidence on the pathogenic role of innate immunity, neuroimmune reaction, and hormonal changes in VKC. Increasing understanding of the pathogenic mechanisms behind VKC may lead to the identification of novel biomarkers for diagnosis and/or potential therapeutic targets in order to improve the management of this challenging condition.

Ten-Year Outcomes of Intravitreal Bevacizumab for Myopic Choroidal Neovascularization: Analysis of Prognostic Factors.

The current standard treatment of myopic choroidal neovascularisation (mCNV) is intravitreal injection of VEGF antagonists. This study was proposed to assess efficacy and safety of intravitreal bevacizumab (IVB) for the treatment of mCNV across a 10-year follow-up. Thirty eyes of thirty patients with treatment-naïve mCNV who underwent IVB and were followed up with for a minimum of ten years were recruited for the present retrospective cohort study. All participants were treated with three monthly IVB at baseline and then evaluated and treated under pro re nata (PRN) schedule. Outcome measures were to determine BCVA changes over years and identify the predictive factors of both final visual outcome and need for retreatment. Analysis of the main involved prognostic factors with correlations among variables is reported. Visual acuity remained stable at 10-year follow-up (p = 0.001) with the greatest improvement at 2 years (p < 0.0001) in all CNV locations. Baseline BCVA correlated positively with final BCVA (ß = 0.88, p < 0.0001, R2: 0.75). No predictive factors for the need of additional injections were identified. Retinal and choroidal thickness significantly reduced over time but without correlation with the number of injections. CNV max height and area significantly decreased at 10 years (p < 0.0001 and p = 0.003, respectively), with complete regression of mCNV lesion in 40% of subjects. Intravitreal bevacizumab resulted as long-term effective and safe therapy for mCNV with sustained results at 10 years.

The Complex Relationship between Diabetic Retinopathy and High-Mobility Group Box: A Review of Molecular Pathways and Therapeutic Strategies.

High-mobility group box 1 (HMGB1) is a protein that is part of a larger family of non-histone nuclear proteins. HMGB1 is a ubiquitary protein with different isoforms, linked to numerous physiological and pathological pathways. HMGB1 is involved in cytokine and chemokine release, leukocyte activation and migration, tumorigenesis, neoangiogenesis, and the activation of several inflammatory pathways. HMGB1 is, in fact, responsible for the trigger, among others, of nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), toll-like receptor-4 (TLR-4), and vascular endothelial growth factor (VEGF) pathways. Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM) that is rapidly growing in number. DR is an inflammatory disease caused by hyperglycemia, which determines the accumulation of oxidative stress and cell damage, which ultimately leads to hypoxia and neovascularization. Recent evidence has shown that hyperglycemia is responsible for the hyperexpression of HMGB1. This protein activates numerous pathways that cause the development of DR, and HMGB1 levels are constantly increased in diabetic retinas in both proliferative and non-proliferative stages of the disease. Several molecules, such as glycyrrhizin (GA), have proven effective in reducing diabetic damage to the retina through the inhibition of HMGB1. The main focus of this review is the growing amount of evidence linking HMGB1 and DR as well as the new therapeutic strategies involving this protein.

Evidence of Pepsin-Related Ocular Surface Damage and Dry Eye (PROD Syndrome) in Patients with Laryngopharyngeal Reflux.

BACKGROUND: patients with laryngopharyngeal reflux (LPR) showed detectable levels of tear pepsin that explain the nasolacrimal obstruction. The purpose of this study was to determine whether patients with LPR show ocular surface changes and to investigate the relationship between lacrimal pepsin concentration and ocular alterations. METHODS: Fifty patients with positive endoscopic signs for LPR and an equal or higher score of 13 and 7 for Reflux Symptom Index and Reflux Finding Score were enrolled. Twenty healthy patients with no reflux disease and dry eye were included as the control group. After evaluation of ocular discomfort symptoms, the tear break-up time test, corneal staining, and tear sampling were performed. Tear pepsin levels were measured using Pep-testTM kit. RESULTS: Patients with LPR showed ocular surface changes including epithelial damage (48%) and impairment of lacrimal function (72%). Tear pepsin levels were detectable in 32 out of 50 (64%) patients with LPR (mean ± SD: 55.4 ± 67.5 ng/mL) and in none of the control subjects. Most of the LPR patients complained of ocular discomfort symptoms, including itching (38%), redness (56%), or foreign body sensation (40%). Tear pepsin levels were significantly correlated with the severity of LPR disease and with ocular surface changes. CONCLUSIONS: A multidisciplinary approach, including ophthalmological evaluation, should be considered in order to improve the management of patients with LPR.

An Update on Oculodermal Melanocytosis and Rare Associated Conditions.

Oculodermal melanocytosis (ODM) is a rare disease, which is characterized by hyperpigmentation of facial skin and several parts of the eye, such as the sclera, conjunctiva, cornea, iris, ciliary body, and choroid. The condition usually affects the Asian female population. The most typical presenting ocular sign is iris heterocromia. Iris hyperpigmentation may be associated with iris mammillations, which are dome-shaped protuberations of the iris surface. They are linked to a higher risk of malignant transformation when present in patients with ODM. Glaucoma is a complication of ODM and is caused by angle abnormalities or mechanical occlusion by melanocytes in an open irido-corneal angle. Choroidal and ciliary body melanoma have a higher incidence in this condition characterized by melanocytosis. Patients presenting ODM should undergo routine ophthalmological examination in order to carefully monitor for glaucoma and melanoma.

Usher's Syndrome Type II: A Comparative Study of Genetic Mutations and Vestibular System Evaluation.

Objective Usher's syndrome type II (USH2) is characterized by moderate to profound congenital hearing loss, later onset of retinitis pigmentosa, and normal vestibular function. Recently, a study investigating the vestibular function of USH2 patients demonstrated a pathologic response to vestibular tests. In this cross-sectional study we performed vestibular tests of a group patients with genetic diagnosis of USH2 syndrome to demonstrate if vestibular damage is present in USH2 patients. Study Design Cross-sectional study. Setting Tertiary referral center. Subjects and Methods Mutated genes of 7 patients with a clinical diagnosis of USH2 were evaluated. Vestibular function was investigated by audiometry, Fitzgerald-Hallpike caloric vestibular testing, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and video head impulse test (v-HIT). Results Genetic tests confirmed the USH2 diagnosis in 5 of 7 patients examined, with 1 patient reporting a unique mutation on genetic tests. Four (80%) of the 5 patients with a genetic diagnosis of USH2 showed pathological O-VEMPs. Two patients (40%) reported bilateral absent or abnormal values of C-VEMPs. The superior semicircular canal presented a significant deficit in 2 (40%) patients. The same 2 cases showed a pathologic response of the v-HIT of the horizontal semicircular canal. Finally, the posterior semicircular canal presented a significant deficit in 4 (40.0%) patients. Conclusion A vestibular evaluation with vestibular evoked myogenic potentials and v-HIT seems to identify latent damage to the vestibular receptors of USH2 patients.

Sturge-Weber Syndrome Associated with Monolateral Ocular Melanocytosis, Iris Mammillations, and Diffuse Choroidal Haemangioma.

We present the case of a 12-year-old boy with Sturge-Weber syndrome and ocular melanocytosis who presented with bilateral naevus flammeus of the face and hyperpigmentation of the right iris associated with ipsilateral iris mammillations. The patient had glaucoma and a diffuse choroidal haemangioma of the right eye. Optical coherence tomography of the anterior segment confirmed iris hyper-pigmentation and did not show abnormalities of the chamber angle structures. B-scan ultrasonography and enhanced depth imaging optical coherence tomography were performed and showed a marked difference in thickness and reflectance between the right and left choroid. Visual field examinations with perimetry showed early defects in the right eye. Peripapillary optical coherence imaging showed borderline values of retinal nerve fibre layer thickness reduction in the right eye. Sturge-Weber syndrome associated with ocular melanocytosis and iris mammillations is an extremely rare condition. This paper highlights the role of multi-imaging methods in the enhanced evaluation of rare diseases towards choosing the most appropriate management strategies and improving the follow-up of patients over time.

Ocular Alterations in a Rare Case of Segmental Neurofibromatosis Type 1 with a Non-Classified Mutational Variant of the NF-1 Gene.

BACKGROUND: Neurofibromatosis type 1 (NF-1) is an autsomal dominant disorder which can occasionally result from somatic mosaicism and manifest as segmental forms of the disease. METHODS: A 37-year-old woman with ascertained NF-1, based on clinical diagnostic criteria and genetic analysis, was referred for ophthalmological evaluation. Genetic analysis, magnetic resonance imaging (MRI), complete ophthalmological examination, and near infrared reflectance (NIR) images at 815 nm of the retina were obtained. RESULTS: Genetic analysis revealed a non-classified mutational variant of the NF-1 gene identified as NM_000267.3:c2084T > C (p.Leu695Pro.T). MRI demonstrated non-symptomatic bilateral optic nerve gliomas. The only cutaneous sign was a subcutaneous neurofibroma of the posterior cervical region. Slit-lamp examination showed bilateral Lisch nodules. NIR images of the retina did not show any choroidal hamartomas. DISCUSSION: We report a rare case of segmental neurofibromatosis with a non-classified mutational variant of the NF-1 gene described in only one previous case in the literature. The patient presented with clinical features of NF-1 localized to the head and neck region, compatible with diagnosis of segmental NF-1. Interestingly, ocular manifestations included bilateral optic nerve gliomas and Lisch nodules, but no choroidal hamartomas.

Investigation of pepsin in tears of children with laryngopharyngeal reflux disease.

OBJECTIVES: Numerous investigations postulated that laryngopharyngeal reflux (LPR) is implicated in the pathogenesis of various upper airway inflammatory diseases as sinusitis or dacryostenosis. The presence of pepsin in tears might be confirmed the presuntive hypothesis of the arrival in the nasolacrimal ducts and precorneal tears film through the laryngopharyngeal reflux of either gastric acid or stomach secretions (pepsin) with inflammatory potentialities. The aim of this preliminary study was to identify the presence or absence of pepsin in the tears collected from children with a high suspicion of LPR who underwent 24-h pH (MII-pH) monitoring to confirm the disease. METHODS: This study enrolled 20 patients suffering from symptoms of laryngopharyngeal reflux that underwent 24-h multichannel intraluminal impedance (MII)-pH monitoring to confirm the disease. The findings of the study group were compared with those of a control group of patients with negative pH monitoring. The quantitative analysis of human pepsin concentration in the tear samples was performed by ELISA method in both groups. RESULTS: Four children (20%) of the study group showed pepsin in the tears. All of the subjects belonging to the control group were negative for its presence. No difference differences in the total number of reflux episodes and the number of weakly basic reflux in the pepsin positive patients vs. pepsin negative children were present. CONCLUSIONS: 20% of the children with diagnosed LPR showed pepsin in the tears. Our specific investigation might provide information regarding sinusitis or dacryostenosis.

Retinitis pigmentosa: evaluation of the vestibular system with cervical and ocular vestibular evoked myogenic potentials and the video head impulse test.

OBJECTIVE: Retinitis pigmentosa (RP) represents a group of inherited disorders in which abnormalities of the photoreceptors lead to progressive visual loss. Night blindness, peripheral visual field loss, and eventual total blindness represent typical visual damage of such disease. No study has previously evaluated the presence of a "latent" vestibular deficit in patients with RP. STUDY DESIGN: Prospective study with caloric test, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and video head impulse test (v-HIT). SETTING: Tertiary referral center. PATIENTS: 16 patients suffering from RP. INTERVENTION: Evaluation of vestibular dysfunction with caloric test, C-VEMPs, O-VEMPs, and the measurement of the vestibular-ocular reflex (VOR) using the v-HIT. RESULTS: Only five patients with RP showed normal values in all the vestibular tests performed. Three patients had an evident deficit at the caloric test, whereas eight (50%) of them had a normal caloric test but a pathological response in at least one of the other vestibular tests performed. No patient of the study showed a bilateral otolith or ampullary dysfunction. CONCLUSION: Our patients with RP unexpectedly showed pathological responses in at least one of the vestibular tests performed. Nowadays, in patients affected by RP, a vestibular diagnostic protocol must include VEMPs and v-HIT to confirm the vestibular damage and to identify selective damage of the vestibular nerve.

Morphologic and vasculature features of the choroid and associated choroid-retinal thickness alterations in neurofibromatosis type 1.

BACKGROUND/AIMS: A normal structural and functional choroid is essential in supplying blood flow to the retina. Neurofibromatosis type 1 (NF1) is a neurocristopathy where the choroid is altered due to the presence of nodules. The present transversal study was conducted to examine choroidal nodules and their effect on choroidal and retinal thickness in NF1 patients. METHODS: Near-infrared reflectance and optical coherence tomography with enhanced depth imaging were used to evaluate choroidal morphology and vasculature in 19 patients with NF1 and 19 healthy, age-matched control subjects. Choroidal thickness, neuroepithelium thickness, photoreceptors together with retinal pigment epithelium (RPE) thickness and outer nuclear layer (ONL) thickness were measured at the fovea and 1000 µm nasal, temporal, superior and inferior to the fovea in NF1 patients and control subjects. Choroidal and neuroepithelium thickness were assessed overlying and adjacent to nodules in NF1 patients. RESULTS: Choroidal nodules were classified as 'dome-shaped' or 'placcoid' subtypes in 17 patients. Small and medium calibre choroidal vessels were observed above dome-shaped nodules where choroidal thickness was significantly reduced. There was a statistically significant reduction in mean choroidal thickness (p=0.013) in NF1 patients with respect to control subjects. The neuroepithelium, photoreceptors together with RPE and ONL had a statistically significant reduction in mean thickness in NF1 patients (p<0.001, p<0.001, p=0.012, respectively). CONCLUSIONS: In NF1, there are dome-shaped and placcoid choroidal nodules which alter choroidal morphology and thickness. There is reduction in mean choroid thickness with generalised thinning of the neuroepithelium, photoreceptors together with RPE and ONL in NF1 patients.

Usher's Syndrome: Evaluation of the Vestibular System with Cervical and Ocular Vestibular Evoked Myogenic Potentials and the Video Head Impulse Test.

OBJECTIVE: The Usher's syndrome (USH) is composed of a group of inherited disorders characterized by a dual sensory impairment of the audiovestibular and visual systems. Despite the established hearing loss, few authors have investigated vestibular dysfunction in these patients.The aim of this article is to investigate otolith or ampullary dysfunction in a group of patients affected by USH by means of a diagnostic protocol using caloric vestibular tests, cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and video head impulse test (v-HIT) to show any selective damage of the vestibular nerve and also to identify if it is present in patients with a previous diagnosis of USH Type II. STUDY DESIGN: Prospective study with C-VEMPs, O-VEMPs, and v-HIT. SETTING: Tertiary referral center. PATIENTS: Fifteen patients with USH. INTERVENTION: Evaluation of otolith dysfunction with caloric test, C-VEMPs, and O-VEMPs and the measurement of the vestibular-ocular reflex using the v-HIT. RESULTS: Only three cases showed normal values of all the vestibular tests performed. O-VEMPs and C-VEMPs appeared pathologic in nine and seven cases, respectively. V-HITs showed ampullary dysfunction in 10 patients. In our study, eight of the 11 patients belonging to the group of USH Type II showed a pathologic response to at least one of the vestibular tests performed. CONCLUSION: Today, in patients affected by USH, any vestibular diagnostic protocol must include VEMPs and v-HIT to confirm the vestibular damage, identify selective deficit of the vestibular nerve, and provide useful information for a correct classification of USH.