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Merino ML, Belmonte J, Rosas J, Acosta MC, Gallar J, Belmonte C. Maximal tear secretion evoked by controlled stimulation of corneal sensory nerves in healthy individuals and dry eye subjects. Ocul Surf 2023; 27:80-88. [PMID: 36396021 DOI: 10.1016/j.jtos.2022.11.005] [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: 02/21/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022]
Abstract
PURPOSE To measure, the tear flow changes evoked in healthy subjects and dry eye disease (DED) patients by controlled sensory stimulation of the eye surface with i-Onion™, a new stimulation device. METHODS Sensory corneal nerves were stimulated with an instrument (i-Onion™) that ejects puffs of CO2 gas (99.9%) at 200 ml·min-1 for 3s, delivered 5 mm from the cornea. Using Schirmer test strips, tear volumes were measured over 3 min in the cornea of one eye before (basal tear volume -BTV) and in the other eye after stimulation of the sensory nerves with CO2 (stimulated tear volume -STV). These measurements were obtained from a control group of adults of either sex (17 students aged 20-30 and 29 subjects without signs of dry eye aged 25-61), a cohort of DED patients (aged 34-75) that included 12 asymptomatic, suspected DED subjects (Schirmer <7 mm and/or TBUT <10s), and 30 Sjögren's syndrome (SS) patients. RESULTS CO2 stimulation significantly increased the tear volume (BTV = 14.6 ± 1.0 mm, STV = 19.0 ± 1.1 mm: n = 46) in 78% of control subjects, reflecting a mean tear reserve volume (TRV = STV-BTV) of 4.4 ± 0.8 mm. Individual differences were wide, and while no increase in reflex tearing was evoked in 30% of subjects with a BTV >10 mm, the remaining 70% responded vigorously to stimulation, even those with a BTV >18 mm. Asymptomatic DED subjects displayed weaker responses to CO2 stimulation, with lower STVs. Both the BTV and STV of SS patients were low, significantly below those of the healthy controls. CONCLUSIONS Measuring the rise in reflex tearing volume evoked by controlled corneal stimulation provides objective information about the tear glands' secretory capacity in health and disease.
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Affiliation(s)
- María L Merino
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain; Oftalmología, Hospital de la Marina Baixa, Villajoyosa, Spain
| | - Javier Belmonte
- Oftalmología, Hospital General Universitario de Alicante, Alicante, Spain
| | - José Rosas
- Reumatología, Hospital de la Marina Baixa, Villajoyosa, Spain
| | - M Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain; Instituto de Investigación Biomédica y Sanitaria de Alicante, San Juan de Alicante, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain.
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Abstract
PURPOSE OF REVIEW Dry eye disease (DED) is a chronic multifactorial disease that affects millions of people worldwide. Despite ongoing research, treatment for DED remains a challenge. Neurostimulation for tear production is a rapidly evolving field that culminated in the development of the intranasal tear neurostimulator (ITN). In this article, we review the neuroanatomy and pathophysiology of tear production and the evolution of neurostimulation for the treatment of DED. RECENT FINDINGS The ITN was approved for commercial use in April 2017. This innovation stemmed from the success of lacrimal nerve and anterior ethmoid nerve stimulation animal studies. Since then, numerous pilot studies and multicenter randomized controlled trials demonstrate increased aqueous tear production, improved DED-related symptoms, and device safety. Recent studies also report the positive effects of intranasal stimulation on mucin and lipid secretion. SUMMARY Neurostimulation for enhanced tear production is a promising new treatment option for DED. Stimulation of the lacrimal nerve and anterior ethmoid nerve both effectively increase tear volume. The ITN is a noninvasive device that effectively increases aqueous tear volume and may improve tear composition, including mucin and lipid concentrations. Further studies are needed to determine proper patient selection and the long-term efficacy of neurostimulation for DED.
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Yazdani M, Elgstøen KBP, Rootwelt H, Shahdadfar A, Utheim ØA, Utheim TP. Tear Metabolomics in Dry Eye Disease: A Review. Int J Mol Sci 2019; 20:E3755. [PMID: 31374809 PMCID: PMC6695908 DOI: 10.3390/ijms20153755] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/26/2019] [Accepted: 07/30/2019] [Indexed: 12/13/2022] Open
Abstract
Dry eye disease (DED) is a multifactorial syndrome that can be caused by alteration in the quality or quantity of the precorneal tear film. It is considered one of the most common ocular conditions leading patients to seek eye care. The current method for diagnostic evaluations and follow-up examinations of DED is a combination of clinical signs and symptoms determined by clinical tests and questionnaires, respectively. The application of powerful omics technologies has opened new avenues toward analysis of subjects in health and disease. Metabolomics is a new emerging and complementary research discipline to all modern omics in the comprehensive analysis of biological systems. The identification of distinct metabolites and integrated metabolic profiles in patients can potentially inform clinicians at an early stage or during monitoring of disease progression, enhancing diagnosis, prognosis, and the choice of therapy. In ophthalmology, metabolomics has gained considerable attention over the past decade but very limited such studies have been reported on DED. This paper aims to review the application of tear metabolomics in DED.
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Affiliation(s)
- Mazyar Yazdani
- Department of Medical Biochemistry, Oslo University Hospital, Ullevål, 0450 Oslo, Norway.
- Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, Ullevål, 0450 Oslo, Norway.
- The Norwegian Dry Eye Clinic, 0366 Oslo, Norway.
| | | | - Helge Rootwelt
- Department of Medical Biochemistry, Oslo University Hospital, 0027 Oslo, Norway
| | - Aboulghassem Shahdadfar
- Center for Eye Research, Department of Ophthalmology, Oslo University Hospital, Ullevål, 0450 Oslo, Norway
| | | | - Tor Paaske Utheim
- Department of Medical Biochemistry, Oslo University Hospital, Ullevål, 0450 Oslo, Norway
- The Norwegian Dry Eye Clinic, 0366 Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, 0450 Oslo, Norway
- Department of Maxillofacial Surgery, Oslo University Hospital, 0450 Oslo, Norway
- Department of Ophthalmology, Vestre Viken Hospital Trust, 3019 Drammen, Norway
- Department of Ophthalmology, Stavanger University Hospital, 4011 Stavanger, Norway
- Department of Clinical Medicine, Faculty of Medicine, University of Bergen, 5020 Bergen, Norway
- Department of Ophthalmology, Sørlandet Hospital Arendal, 4604 Arendal, Norway
- Department of Life Sciences and Health, Oslo Metropolitan University, 0130 Oslo, Norway
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Kawakita T. Regeneration of Lacrimal Gland Function to Maintain the Health of the Ocular Surface. Invest Ophthalmol Vis Sci 2019; 59:DES169-DES173. [PMID: 30481823 DOI: 10.1167/iovs.17-23576] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Dry eye is a multifactorial disease that is one of the most common diseases worldwide. A major cause of dry eye is the deficiency of aqueous tears, which are mainly secreted from the lacrimal gland. The lacrimal gland plays an important role in maintaining the health of the ocular surface and protecting it from environmental exposure. Dry eye can lead to ocular irritation and discomfort, as well as severe ocular surface diseases (e.g., ocular infections, corneal ulcerations, and ocular surface keratinization). These severe diseases can be induced by an atrophied or injured lacrimal gland; current therapies cannot completely restore the function of lacrimal gland. To develop more definitive therapies, it is important to understand lacrimal gland biology at the molecular level, as well as inflammatory processes affecting the function of the gland. During severe inflammation, the tissue structure of the lacrimal gland is destroyed; it is replaced by scar formation during wound healing, which leads to lacrimal gland dysfunction. Using an animal model of lacrimal gland dysfunction, many investigators have studied molecular mechanisms of inflammation in the lacrimal gland. To restore lacrimal gland function, the lacrimal acini must be restored in their niche. Notably, organ transplantation therapies have been reported to restore lacrimal gland function, directly or indirectly, in animal models. In this review, we describe the current understanding of the lacrimal gland as the therapeutic target for dry eye diseases, as well as recent advances in the field of lacrimal gland cell-based therapy to treat severe dry eye diseases.
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Affiliation(s)
- Tetsuya Kawakita
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.,Department of Ophthalmology, Kitasato University Kitasato Institute Hospital, Tokyo, Japan
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Mathebula SD, Makunyane PS. Ocular surface disorder among HIV and AIDS patients using antiretroviral drugs. AFRICAN VISION AND EYE HEALTH 2019. [DOI: 10.4102/aveh.v78i1.457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Abstract
Dry eye disease (DED) is a commonly encountered condition in general ophthalmology practice and imparts a significant socioeconomic burden. Despite its prevalence, there remain challenges regarding its diagnosis and management. A major reason behind these challenges is the fact that DED represents an umbrella term that encompasses many different underlying conditions and pathophysiological mechanisms. The purpose of this article is to highlight aspects of DED pathophysiology and focus on targeted diagnostic and therapeutic approaches to this multifactorial, chronic condition.
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Affiliation(s)
- Shruti Aggarwal
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miller School of Miami, 900 NW 17th Street, Miami, FL, 33136, USA
| | - Anat Galor
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miller School of Miami, 900 NW 17th Street, Miami, FL, 33136, USA.,Department of Ophthalmology, Miami Veterans Affairs Medical Center, 1201 NW 16th St., Miami, FL, 33125 , USA
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Dieckmann G, Fregni F, Hamrah P. Neurostimulation in dry eye disease-past, present, and future. Ocul Surf 2018; 17:20-27. [PMID: 30419304 DOI: 10.1016/j.jtos.2018.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/03/2018] [Accepted: 11/07/2018] [Indexed: 01/19/2023]
Abstract
Neuromodulation is a novel approach that utilizes electrical signals, pharmaceutical agents, or other forms of energy to modulate abnormal neural function through neurostimulation. Neurostimulation is a novel technique that uses electrical currents to stimulate the nervous system. During the recent few decades, neuromodulation has gained significant attention, in particular for the treatment of chronic neurological diseases, due to its success in treating patients unresponsive to conventional pharmacological therapies. Dry eye disease (DED) is a chronic, multifactorial disease that affects millions of people worldwide. Recent data have demonstrated that neurosensory abnormalities contribute to the pathogenesis of DED. Current mainstays of dry eye therapy include lubrication, tear retention, and anti-inflammatory therapies, among others. The recent development of intranasal neurostimulation therapy for DED utilizes the nasolacrimal reflex as an alternative pathway, not only to increase tear production via increased lacrimation, but also to target other tear film components, such as mucin and meibum secretion, promoting tear film homeostasis. This review aims to describe the different types of neuromodulation devices available and their application for non-ocular diseases, as well as to review recent advances and literature on ocular neurostimulation.
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Affiliation(s)
- Gabriela Dieckmann
- Cornea Service, New England Eye Center, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Center for Translational Ocular Immunology, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Felipe Fregni
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Pedram Hamrah
- Cornea Service, New England Eye Center, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA; Center for Translational Ocular Immunology, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA.
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Effects of ambient humidity on the Cochet-Bonnet aesthesiometer. Eye (Lond) 2018; 32:1644-1651. [PMID: 29921953 DOI: 10.1038/s41433-018-0150-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/11/2018] [Accepted: 05/16/2018] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The Cochet-Bonnet (COBO) aesthesiometer is the current standard in corneal sensitivity assessment. This study investigates the influence of ambient room humidity levels on the stimulus force exerted by the instrument. METHODS A COBO instrument (Luneau Opthalmologie) with 0.12 mm nominal nylon filament diameter was placed in an environment chamber (Electro-tech systems Inc. PA, USA) at 25 °C and relative humidity (%RH) set to either 20-80%, in 10% steps. After 12 h in the chamber at a chosen %RH level, the instrument was removed and exerted force measured by pressing the nylon filament onto the plate of an analytical microbalance (Mettler-Toledo AB265; precision ±0.0001 g) at a perpendicular angle, by a predetermined amount. Exerted force onto the microbalance was recorded in grams for a specified filament length. Procedure was repeated for filament lengths 10-60 mm, in 5 mm steps. The instrument was returned to the chamber and procedure repeated 5 times, before repeating at the next %RH setting (random order). Measurements at each filament lengths were compared using one-way ANOVA and post-hoc Tukey's range test. A p-value < 0.05 denoted statistical significance. RESULTS Significant differences in exerted force were observed with alteration in %RH levels for each filament length (all p < 0.001). Exerted force decreased significantly with an increase in %RH for all filament lengths, with the average force decreasing by 15% with each 10% rise in %RH. CONCLUSIONS This study confirms previous suggestions that the rigidity of the COBO nylon filament is affected by ambient room humidity levels, with implications on the stimulus force delivered by the instrument. A conversion table is provided for converting filament lengths to pressure for a range of relative humidity levels.
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Bron AJ, de Paiva CS, Chauhan SK, Bonini S, Gabison EE, Jain S, Knop E, Markoulli M, Ogawa Y, Perez V, Uchino Y, Yokoi N, Zoukhri D, Sullivan DA. TFOS DEWS II pathophysiology report. Ocul Surf 2017; 15:438-510. [PMID: 28736340 DOI: 10.1016/j.jtos.2017.05.011] [Citation(s) in RCA: 1001] [Impact Index Per Article: 143.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 05/26/2017] [Indexed: 12/18/2022]
Abstract
The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.
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Affiliation(s)
- Anthony J Bron
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Vision and Eye Research Unit, Anglia Ruskin University, Cambridge, UK.
| | - Cintia S de Paiva
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
| | - Sunil K Chauhan
- Schepens Eye Research Institute & Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Stefano Bonini
- Department of Ophthalmology, University Campus Biomedico, Rome, Italy
| | - Eric E Gabison
- Department of Ophthalmology, Fondation Ophtalmologique Rothschild & Hôpital Bichat Claude Bernard, Paris, France
| | - Sandeep Jain
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Erich Knop
- Departments of Cell and Neurobiology and Ocular Surface Center Berlin, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Maria Markoulli
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Yoko Ogawa
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Victor Perez
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Yuichi Uchino
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Norihiko Yokoi
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Driss Zoukhri
- Tufts University School of Dental Medicine, Boston, MA, USA
| | - David A Sullivan
- Schepens Eye Research Institute & Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
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