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Watson SL, Le DTM. Corneal neuropathic pain: a review to inform clinical practice. Eye (Lond) 2024; 38:2350-2358. [PMID: 38627548 PMCID: PMC11306374 DOI: 10.1038/s41433-024-03060-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/25/2024] [Accepted: 04/02/2024] [Indexed: 08/09/2024] Open
Abstract
Corneal neuropathic pain (CNP) is a poorly defined disease entity characterised by an aberrant pain response to normally non-painful stimuli and categorised into having peripheral and central mechanisms, with the former responding to instillation of topical anaesthetic. CNP is a challenging condition to diagnose due to numerous aetiologies, an absence of clinical signs and ancillary tests (in vivo confocal microscopy and esthesiometry), lacking the ability to confirm the diagnosis and having limited availability. Symptomatology maybe mirrored by severe and chronic forms of dry eye disease (DED), often leading to misdiagnosis and inadequate treatment. In practice, patients with suspected CNP can be assessed with questionnaires to elicit symptoms. A thorough ocular assessment is also performed to exclude any co-existent ocular conditions. A medical and mental health history should be sought due to associations with autoimmune disease, chronic pain syndromes, anxiety and depression. Management begins with communicating to the patient the nature of their condition. Ophthalmologists can prescribe topical therapies such as autologous serum eyedrops to optimise the ocular surface and promote neural regeneration. However, a multi-disciplinary treatment approach is often required, including mental health support, particularly when there are central mechanisms. General practitioners, pain specialists, neurologists and psychologists may be needed to assist with oral and behavioural therapies. Less data is available to support the safety and efficacy of adjuvant and surgical therapies and the long-term natural history remains to be determined. Hence clinical trials and registry studies are urgently needed to fill these data gaps with the aim to improve patient care.
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Affiliation(s)
- Stephanie L Watson
- The University of Sydney, Save Sight Institute, Faculty of Medicine and Health, Sydney, NSW, Australia.
- Sydney Eye Hospital, Sydney, NSW, Australia.
| | - Damien Tuan-Man Le
- The University of Sydney, Save Sight Institute, Faculty of Medicine and Health, Sydney, NSW, Australia
- Sydney Eye Hospital, Sydney, NSW, Australia
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Wu J, Yuan T, Fu D, Xu R, Zhang W, Li S, Ding J, Feng L, Xia Y, Wang J, Li W, Han Y. An experimental model for primary neuropathic corneal pain induced by long ciliary nerve ligation in rats. Pain 2024; 165:1391-1403. [PMID: 38227559 DOI: 10.1097/j.pain.0000000000003141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/28/2023] [Indexed: 01/18/2024]
Abstract
ABSTRACT Neuropathic corneal pain (NCP) is a new and ill-defined disease characterized by pain, discomfort, aching, burning sensation, irritation, dryness, and grittiness. However, the mechanism underlying NCP remain unclear. Here, we reported a novel rat model of primary NCP induced by long ciliary nerve (LCN) ligation. After sustained LCN ligation, the rats developed increased corneal mechanical and chemical sensitivity, spontaneous blinking, and photophobia, which were ameliorated by intraperitoneal injection of morphine or gabapentin. However, neither tear reduction nor corneal injury was observed in LCN-ligated rats. Furthermore, after LCN ligation, the rats displayed a significant reduction in corneal nerve density, as well as increased tortuosity and beading nerve ending. Long ciliary nerve ligation also notably elevated corneal responsiveness under resting or menthol-stimulated conditions. At a cellular level, we observed that LCN ligation increased calcitonin gene-related peptide (neuropeptide)-positive cells in the trigeminal ganglion (TG). At a molecular level, upregulated mRNA levels of ion channels Piezo2, TRPM8, and TRPV1, as well as inflammatory factors TNF-α, IL-1β, and IL-6, were also detected in the TG after LCN ligation. Meanwhile, consecutive oral gabapentin attenuated LCN ligation-induced corneal hyperalgesia and increased levels of ion channels and inflammation factors in TG. This study provides a reliable primary NCP model induced by LCN ligation in rats using a simple, minimally invasive surgery technique, which may help shed light on the underlying cellular and molecular bases of NCP and aid in developing a new treatment for the disease.
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Affiliation(s)
- Jinhong Wu
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Tianjie Yuan
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Danyun Fu
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Rui Xu
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Wenna Zhang
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Shuangshuang Li
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Jiahui Ding
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Lili Feng
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Ying Xia
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Jijiang Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Xuhui District, Shanghai, China
| | - Wenxian Li
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
| | - Yuan Han
- Department of Anesthesiology, Eye & ENT Hospital of Fudan University, Xuhui District, Shanghai, China
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Patel NT, Martinek A, Shaikh R, Kahar P, Khanna D. COVID-19 and Its Ophthalmic Manifestations: A Literature Review. Cureus 2024; 16:e55571. [PMID: 38576676 PMCID: PMC10993080 DOI: 10.7759/cureus.55571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 03/04/2024] [Indexed: 04/06/2024] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus discovered in late 2019 in Wuhan, Hubei Province, China. The virus has now developed into a full-scale global pandemic affecting hundreds of millions of people to date. A majority of cases present with nonspecific acute upper respiratory symptoms. A wide range of systemic symptoms has been reported, with some patients presenting with nonspecific extrapulmonary symptoms. Recently, there has been an increased association of COVID-19-positive patients presenting with ocular symptoms. As an increasing number of patients present with ophthalmic manifestations, recognizing these visual symptoms is of utmost importance. Some patients may present with ocular symptoms as the first indication of COVID-19 infection; quickly isolating and starting treatment can aid in stopping the spread of this novel coronavirus. This review will describe the current epidemiology and pathophysiology of SARS-CoV-2, emphasizing the ophthalmic manifestations and their clinical course progression. Further, we will be reporting on the growing number of rare ocular manifestations that have occurred in some COVID-19-positive patients, along with the route of transmission, specific manifestations, and the treatment methods for both these pulmonary and extrapulmonary symptoms, specifically the ocular manifestations.
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Affiliation(s)
- Neal T Patel
- Department of Foundational Sciences, Dr. Kiran C. Patel College of Osteopathic Medicine Nova Southeastern University, Fort Lauderdale, USA
| | - Alexander Martinek
- Department of Foundational Sciences, Morehouse School of Medicine, Atlanta, USA
| | - Raheel Shaikh
- Department of Medicine, Dr. Kiran C. Patel College of Osteopathic Medicine Nova Southeastern University, Fort Lauderdale, USA
| | - Payal Kahar
- Department of Health Sciences, Florida Gulf Coast University, Fort Myers, USA
| | - Deepesh Khanna
- Department of Foundational Sciences, Dr. Kiran C. Patel College of Osteopathic Medicine Nova Southeastern University, Fort Lauderdale, USA
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Wong NSQ, Liu C, Lin MTY, Lee IXY, Tong L, Liu YC. Neuropathic Corneal Pain after Coronavirus Disease 2019 (COVID-19) Infection. Diseases 2024; 12:37. [PMID: 38391784 PMCID: PMC10887979 DOI: 10.3390/diseases12020037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 02/24/2024] Open
Abstract
INTRODUCTION This is a case report of a patient with neuropathic corneal pain after coronavirus disease 2019 (COVID-19) infection. METHODS A previously healthy 27-year-old female presented with bilateral eye pain accompanied by increased light sensitivity 5 months after COVID-19 infection. She was diagnosed with neuropathic corneal pain based on clear corneas without fluorescein staining, alongside the presence of microneuromas, dendritic cells, and activated stromal keratocytes identified bilaterally on in vivo confocal microscopy. RESULTS The patient's tear nerve growth factor, substance P, and calcitonin gene-related peptide levels were 5.9 pg/mL, 2978.7 pg/mL, and 1.1 ng/mL, respectively, for the right eye and 23.1 pg/mL, 4798.7 pg/mL, and 1.2 ng/mL, respectively, for the left eye, suggesting corneal neuroinflammatory status. After 6 weeks of topical 0.1% flurometholone treatment, decreased microneuroma size, less extensive dendritic cells, and reduced tear nerve growth factor and substance P levels were observed. The scores on the Ocular Pain Assessment Survey showed an improvement in burning sensation and light sensitivity, decreasing from 80% and 70% to 50% for both. CONCLUSIONS Neuropathic corneal pain is a potential post-COVID-19 complication that warrants ophthalmologists' and neurologists' attention.
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Affiliation(s)
- Natalie Shi Qi Wong
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Chang Liu
- Singapore Eye Research Institute, Singapore 169856, Singapore
| | | | | | - Louis Tong
- Singapore Eye Research Institute, Singapore 169856, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Yu-Chi Liu
- Singapore Eye Research Institute, Singapore 169856, Singapore
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
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Cañadas P, Gonzalez-Vides L, Alberquilla García-Velasco M, Arriola P, Guemes-Villahoz N, Hernández-Verdejo JL. Neuroinflammatory Findings of Corneal Confocal Microscopy in Long COVID-19 Patients, 2 Years after Acute SARS-CoV-2 Infection. Diagnostics (Basel) 2023; 13:3188. [PMID: 37892009 PMCID: PMC10605628 DOI: 10.3390/diagnostics13203188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 10/09/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023] Open
Abstract
OBJECTIVE To describe corneal confocal microscopy findings in patients with long COVID-19 with persistent symptoms over 20 months after SARS-CoV-2 infection. DESIGN A descriptive cross-sectional study that included a total of 88 patients; 60 patients with Long COVID-19 and 28 controls. Long COVID-19 diagnosis was established according to the World Health Organization criteria. Corneal confocal microscopy using a Heidelberg Retina Tomograph II (Heidelberg Engineering, Heidelberg, Germany) was performed to evaluate sub-basal nerve plexus morphology (corneal nerve fiber density, nerve fiber length, nerve branch density, nerve fiber total branch density, nerve fiber area, and nerve fiber width). Dendritic cell density and area, along with microneuromas and other morphological changes of the nerve fibers were recorded. RESULTS Long COVID-19 patients presented with reduced corneal nerve density and branch density as well as shorter corneal nerves compared to the control group. Additionally, Long COVID-19 patients showed an increased density of dendritic cells also with a greater area than that found in the control group of patients without systemic diseases. Microneuromas were detected in 15% of Long COVID-19 patients. CONCLUSIONS Long COVID-19 patients exhibited altered corneal nerve parameters and increased DC density over 20 months after acute SARS-CoV-2 infection. These findings are consistent with a neuroinflammatory condition hypothesized to be present in patients with Long COVID-19, highlighting the potential role of corneal confocal microscopy as a promising noninvasive technique for the study of patients with Long COVID-19.
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Affiliation(s)
- Pilar Cañadas
- Optometry and Vision Department, School of Optometry, Complutense University of Madrid, 28037 Madrid, Spain; (L.G.-V.); (M.A.G.-V.)
| | - Leonela Gonzalez-Vides
- Optometry and Vision Department, School of Optometry, Complutense University of Madrid, 28037 Madrid, Spain; (L.G.-V.); (M.A.G.-V.)
- Education Faculty, University of Costa Rica, San José 11501-2060, Costa Rica
| | - Marta Alberquilla García-Velasco
- Optometry and Vision Department, School of Optometry, Complutense University of Madrid, 28037 Madrid, Spain; (L.G.-V.); (M.A.G.-V.)
| | - Pedro Arriola
- Department of Ophthalmology, Hospital Clínico San Carlos, 28040 Madrid, Spain
| | | | - Jose Luis Hernández-Verdejo
- Optometry and Vision Department, School of Optometry, Complutense University of Madrid, 28037 Madrid, Spain; (L.G.-V.); (M.A.G.-V.)
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