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Teo AWJ, Mansoor H, Sim N, Lin MTY, Liu YC. In Vivo Confocal Microscopy Evaluation in Patients with Keratoconus. J Clin Med 2022; 11:393. [PMID: 35054085 PMCID: PMC8778820 DOI: 10.3390/jcm11020393] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 02/05/2023] Open
Abstract
Keratoconus is the most common primary corneal ectasia characterized by progressive focal thinning. Patients experience increased irregular astigmatism, decreased visual acuity and corneal sensitivity. Corneal collagen crosslinking (CXL), a minimally invasive procedure, is effective in halting disease progression. Historically, keratoconus research was confined to ex vivo settings. In vivo confocal microscopy (IVCM) has been used to examine the corneal microstructure clinically. In this review, we discuss keratoconus cellular changes evaluated by IVCM before and after CXL. Cellular changes before CXL include decreased keratocyte and nerve densities, disorganized subbasal nerves with thickening, increased nerve tortuosity and shortened nerve fibre length. Repopulation of keratocytes occurs up to 1 year post procedure. IVCM also correlates corneal nerve status to functional corneal sensitivity. Immediately after CXL, there is reduced nerve density and keratocyte absence due to mechanical removal of the epithelium and CXL effect. Nerve regeneration begins after 1 month, with nerve fibre densities recovering to pre-operative levels between 6 months to 1 year and remains stable up to 5 years. Nerves remain tortuous and nerve densities are reduced. Corneal sensitivity is reduced immediately postoperatively but recovers with nerve regeneration. Our article provides comprehensive review on the use of IVCM imaging in keratoconus patients.
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Affiliation(s)
- Alvin Wei Jun Teo
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore;
| | - Hassan Mansoor
- Al Shifa Trust Eye Hospital, Jhelum Road, Rawalpindi 46000, Pakistan;
| | - Nigel Sim
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 168751, Singapore;
| | - Molly Tzu-Yu Lin
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
| | - Yu-Chi Liu
- Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore 168751, Singapore;
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore 169856, Singapore;
- Cornea and Refractive Surgery Group, Singapore Eye Research Institute, Singapore 169856, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore 169857, Singapore
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[Histological changes in keratoconus and wound healing after corneal cross-linking]. Ophthalmologe 2021; 119:342-349. [PMID: 34874483 DOI: 10.1007/s00347-021-01537-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Keratoconus is classified as a corneal ectasia and is a multifactorial disease. In those affected, mostly adolescent patients visual deterioration occurs due to the development of irregular astigmatism. Treatment by corneal cross-linking (CXL) has been indicated in progressive disease for several years. OBJECTIVE To present the pathophysiology and histological changes in keratoconus as well as wound healing processes after CXL and their potential complications. MATERIAL AND METHODS Histological changes in keratoconus as well as wound healing processes after CXL and their potential complications are presented based on histological examination of corneal specimens with keratoconus with and without a condition after CXL. Relevant literature and own data are analyzed and discussed. RESULTS Besides inflammatory processes, atopic and genetic dispositions play a role in the development of keratoconus. The histological characteristics of keratoconus include changes in the epithelium, Bowman's layer and stroma. Wound healing processes after CXL include healing of the surface epithelium and transient loss of keratocytes and nerve fibers. CONCLUSION Keratoconus shows characteristic histopathological changes, such as epithelial irregularities, stromal thinning and breaks of Bowman's layer, whereas the endothelium and Descemet's membrane remain unchanged (apart from cases of corneal hydrops). After CXL wound healing processes can be followed primarily in vivo by confocal microscopy. Complications after CXL are rare. Persistent loss of keratocytes can be clinically manifested as a visually relevant scar.
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Non-invasive detection of corneal sub-basal nerve plexus changes in multiple myeloma patients by confocal laser scanning microscopy. Biosci Rep 2021; 40:226598. [PMID: 33026069 PMCID: PMC7578619 DOI: 10.1042/bsr20193563] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 09/17/2020] [Accepted: 10/06/2020] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Confocal laser scanning microscopy (CLSM) is a non-invasive technique for cellular in vivo imaging of the human cornea. CLSM screening was evaluated for early detection of corneal nerve morphology changes and neuropathogenic events in different stage multiple myeloma (MM) patients. As MM patients show disease as well as therapy-related neuropathological symptoms, CLSM potentially provides a tool for non-invasive early detection of neuropathogenic events. CLSM findings were compared with the severity of peripheral neuropathic (PNP) symptoms. METHODS The study enrolled 25 MM patients in which bilateral ophthalmologic examination was performed including unilateral CLSM. Further peripheral nerve function was clinically evaluated using the conventional neuropathy symptom and neuropathy deficit scores (NDSs). RESULTS In 18/25 MM patients, CLSM detected atypical morphological appearance of bulb-like enlarged nerve endings in the corneal sub-basal nerve plexus. These neuromas were only found in patients showing moderate to severe PNP, in patients with mild or lacking PNP neuromas were absent. CONCLUSIONS CLSM provides a novel non-invasive diagnostic tool for identification of neuromas in cancer patients affected by therapy or disease-related neuropathologies, perspectival allowing early neuronal degenerative process detection and monitoring.
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Marfurt C, Anokwute MC, Fetcko K, Mahony-Perez E, Farooq H, Ross E, Baumanis MM, Weinberg RL, McCarron ME, Mankowski JL. Comparative Anatomy of the Mammalian Corneal Subbasal Nerve Plexus. Invest Ophthalmol Vis Sci 2019; 60:4972-4984. [PMID: 31790560 PMCID: PMC6886725 DOI: 10.1167/iovs.19-28519] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 10/24/2019] [Indexed: 12/20/2022] Open
Abstract
Purpose The subbasal nerve plexus (SNP) is the densest and most recognizable component of the mammalian corneal innervation; however, the anatomical configuration of the SNP in most animal models remains incompletely described. The purpose of the current study is to describe in detail the SNP architecture in eight different mammals, including several popular animal models used in cornea research. Methods Corneal nerves in mouse, rat, guinea pig, rabbit, dog, macaque, domestic pig, and cow eyes were stained immunohistochemically with antiserum directed against neurotubulin. SNP architecture was documented by digital photomicrography and large-scale reconstructions, that is, corneal nerve maps, using a drawing tube attached to a light microscope. Results Subbasal nerve fibers (SNFs) in mice, rats, guinea pigs, dogs, and macaques radiated centrally from the corneoscleral limbus toward the corneal apex in a whorl-like or spiraling pattern. SNFs in rabbit and bovine corneas swept horizontally across the ocular surface in a temporal-to-nasal direction and converged on the inferonasal limbus without forming a spiral. SNFs in the pig cornea radiated centrifugally in all directions, like a starburst, from a focal point located equidistant between the corneal apex and the superior pole. Conclusions The results of the present study have demonstrated for the first time substantial interspecies differences in the architectural organization of the mammalian SNP. The physiological significance of these different patterns and the mechanisms that regulate SNP pattern formation in the mammalian cornea remain incompletely understood and warrant additional investigation.
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Affiliation(s)
- Carl Marfurt
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Miracle C. Anokwute
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Kaleigh Fetcko
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Erin Mahony-Perez
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Hassan Farooq
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Emily Ross
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Maraya M. Baumanis
- Indiana University School of Medicine-Northwest-Gary, Gary, Indiana, United States
| | - Rachel L. Weinberg
- Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Megan E. McCarron
- Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Joseph L. Mankowski
- Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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Corneal nerves in health and disease. Prog Retin Eye Res 2019; 73:100762. [DOI: 10.1016/j.preteyeres.2019.05.003] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 04/25/2019] [Accepted: 05/01/2019] [Indexed: 12/15/2022]
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Ross AR, Al-Aqaba MA, Almaazmi A, Messina M, Nubile M, Mastropasqua L, Dua HS, Said DG. Clinical and in vivo confocal microscopic features of neuropathic corneal pain. Br J Ophthalmol 2019; 104:768-775. [DOI: 10.1136/bjophthalmol-2019-314799] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/06/2019] [Accepted: 08/22/2019] [Indexed: 12/26/2022]
Abstract
AimsTo describe clinical and in vivo confocal microscopy (IVCM) features of neuropathic corneal pain (NCP) without clinically visible signs.MethodsProspective, observational study of 27 eyes of 14 patients who had continuous severe ocular pain for one or more years, with minimal or no ocular surface signs and were non-responsive to topical lubricants, steroids and/or ciclosporin. All patients were evaluated using Ocular Surface Disease Index, Oxford grading scale, Schirmer test 1, Cochet Bonnet esthesiometry and response to topical anaesthesia. Central and paracentral regions of the cornea of patients and seven healthy controls were studied by IVCM. Corneal epithelial thickness and sub-basal nerve density were measured in patients and controls.ResultsFour patients responded to topical anaesthesia (responsive group (RG)), indicating peripheral NCP while 10 patients did not show any improvement (non-responsive group (NRG)), indicating central NCP. Schirmer-1 test was within normal limits in the RG but significantly greater in the NRG (p<0.001). None of the other clinical parameters nor corneal epithelial thickness were statistically significantly different. The sub-basal nerve density was significantly reduced (p<0.008) in patients compared with controls. Stroma of all patients demonstrated activated keratocytes and spindle, lateral and stump microneuromas. There was a statistically significant greater number of microneuromas (p<0.0001) and activated keratocytes in RG compared with NRG.ConclusionNCP without visible clinical signs does not represent typical dry eye disease. Distinct signs demonstrated on IVCM suggest that peripheral NCP, which responds to topical anaesthesia, and central NCP, which does not, are separate entities.
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Dua HS, Said DG, Messmer EM, Rolando M, Benitez-del-Castillo JM, Hossain PN, Shortt AJ, Geerling G, Nubile M, Figueiredo FC, Rauz S, Mastropasqua L, Rama P, Baudouin C. Neurotrophic keratopathy. Prog Retin Eye Res 2018; 66:107-131. [DOI: 10.1016/j.preteyeres.2018.04.003] [Citation(s) in RCA: 179] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 01/09/2023]
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Nebbioso M, Del Regno P, Gharbiya M, Sacchetti M, Plateroti R, Lambiase A. Analysis of the Pathogenic Factors and Management of Dry Eye in Ocular Surface Disorders. Int J Mol Sci 2017; 18:E1764. [PMID: 28805710 PMCID: PMC5578153 DOI: 10.3390/ijms18081764] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 07/30/2017] [Accepted: 08/09/2017] [Indexed: 12/17/2022] Open
Abstract
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.
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Affiliation(s)
- Marcella Nebbioso
- Department of Sense Organs, Policlinico Umberto I, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Paola Del Regno
- Department of Sense Organs, Policlinico Umberto I, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Magda Gharbiya
- Department of Sense Organs, Policlinico Umberto I, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Marta Sacchetti
- Department of Sense Organs, Policlinico Umberto I, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Rocco Plateroti
- Department of Sense Organs, Policlinico Umberto I, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Alessandro Lambiase
- Department of Sense Organs, Policlinico Umberto I, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
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Abstract
Pain associated with mechanical, chemical, and thermal heat stimulation of the ocular surface is mediated by trigeminal ganglion neurons, while cold thermoreceptors detect wetness and reflexly maintain basal tear production and blinking rate. These neurons project into two regions of the trigeminal brain stem nuclear complex: ViVc, activated by changes in the moisture of the ocular surface and VcC1, mediating sensory-discriminative aspects of ocular pain and reflex blinking. ViVc ocular neurons project to brain regions that control lacrimation and spontaneous blinking and to the sensory thalamus. Secretion of the main lacrimal gland is regulated dominantly by autonomic parasympathetic nerves, reflexly activated by eye surface sensory nerves. These also evoke goblet cell secretion through unidentified efferent fibers. Neural pathways involved in the regulation of meibomian gland secretion or mucin release have not been identified. In dry eye disease, reduced tear secretion leads to inflammation and peripheral nerve damage. Inflammation causes sensitization of polymodal and mechano-nociceptor nerve endings and an abnormal increase in cold thermoreceptor activity, altogether evoking dryness sensations and pain. Long-term inflammation and nerve injury alter gene expression of ion channels and receptors at terminals and cell bodies of trigeminal ganglion and brainstem neurons, changing their excitability, connectivity and impulse firing. Perpetuation of molecular, structural and functional disturbances in ocular sensory pathways ultimately leads to dysestesias and neuropathic pain referred to the eye surface. Pain can be assessed with a variety of questionaires while the status of corneal nerves is evaluated with esthesiometry and with in vivo confocal microscopy.
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Gomes JAP, Azar DT, Baudouin C, Efron N, Hirayama M, Horwath-Winter J, Kim T, Mehta JS, Messmer EM, Pepose JS, Sangwan VS, Weiner AL, Wilson SE, Wolffsohn JS. TFOS DEWS II iatrogenic report. Ocul Surf 2017; 15:511-538. [PMID: 28736341 DOI: 10.1016/j.jtos.2017.05.004] [Citation(s) in RCA: 250] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 05/02/2017] [Indexed: 01/04/2023]
Abstract
Dry eye can be caused by a variety of iatrogenic interventions. The increasing number of patients looking for eye care or cosmetic procedures involving the eyes, together with a better understanding of the pathophysiological mechanisms of dry eye disease (DED), have led to the need for a specific report about iatrogenic dry eye within the TFOS DEWS II. Topical medications can cause DED due to their allergic, toxic and immuno-inflammatory effects on the ocular surface. Preservatives, such as benzalkonium chloride, may further aggravate DED. A variety of systemic drugs can also induce DED secondary to multiple mechanisms. Moreover, the use of contact lens induces or is associated with DED. However, one of the most emblematic situations is DED caused by surgical procedures such as corneal refractive surgery as in laser-assisted in situ keratomileusis (LASIK) and keratoplasty due to mechanisms intrinsic to the procedure (i.e. corneal nerve cutting) or even by the use of postoperative topical drugs. Cataract surgery, lid surgeries, botulinum toxin application and cosmetic procedures are also considered risk factors to iatrogenic DED, which can cause patient dissatisfaction, visual disturbance and poor surgical outcomes. This report also presents future directions to address iatrogenic DED, including the need for more in-depth epidemiological studies about the risk factors, development of less toxic medications and preservatives, as well as new techniques for less invasive eye surgeries. Novel research into detection of early dry eye prior to surgeries, efforts to establish appropriate therapeutics and a greater attempt to regulate and oversee medications, preservatives and procedures should be considered.
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Affiliation(s)
- José Alvaro P Gomes
- Dept. of Ophthalmology and Visual Sciences, Federal University of Sao Paulo/Paulista School of Medicine (UNIFESP/EPM), São Paulo, SP, Brazil.
| | - Dimitri T Azar
- University of Illinois College of Medicine, Chicago, IL, USA
| | | | - Nathan Efron
- School of Optometry and Vision Science, Queensland University of Technology, Queensland, Australia
| | - Masatoshi Hirayama
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo, Japan
| | | | - Terry Kim
- Duke University School of Medicine, Durham, NC, USA; Duke University Eye Center, Durham, NC, USA
| | | | - Elisabeth M Messmer
- Department of Ophthalmology, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Jay S Pepose
- Washington University School of Medicine, St. Louis, MO, USA
| | | | | | - Steven E Wilson
- Cole Eye Institute, The Cleveland Clinic, Cleveland, OH, USA
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Brandão LPNDA, Vilar L, Cavalcanti BM, Brandão PHA, Arantes TEFE, Campos JM. Serum levels of vitamin A, visual function and ocular surface after bariatric surgery. ARQUIVOS DE GASTROENTEROLOGIA 2017; 54:65-69. [PMID: 28079243 DOI: 10.1590/s0004-2803.2017v54n1-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Accepted: 08/22/2016] [Indexed: 01/09/2023]
Abstract
BACKGROUND - Bariatric surgery is the most effective treatment for severe obesity, but the surgery increases the risk of developing nutritional deficiencies, such as vitamin A deficiency. In human metabolism, vitamin A plays a role in vision. OBJECTIVE - To evaluate serum vitamin A, visual function and ocular surface of patients undergoing bariatric surgery. METHODS - A cross-sectional and analytical study was conduced with 28 patients undergoing bariatric surgery for at least 6 months. Ophthalmologic evaluation was done through color vision test, contrast sensitivity test, ocular surface tests and confocal microscopy, as well as vitamin A serum measurement. RESULTS - Vertical sleeve gastrectomy was performed in seven (25.0%) patients and Roux -en-Y gastric by-pass in 21 (75.0%). Mean serum vitamin A level was 1.7±0.5 µmoL/L. Most patients (60.7%) had symptoms of dry eye. Five (17.9%) patients had contrast sensitivity impairment and 18 (64.3%) color vision changes. In the group of patients undergoing Roux -en-Y gastric by-pass , mean vitamin A levels were 1.8±0.6 µmoL/L, whereas they were 1.7±0.5 µmoL/L in patients submitted to the restrictive technique vertical sleeve gastrectomy . The analysis of the influence of serum levels of vitamin A in the visual function and ocular surface was performed by Pearson correlation test and there was no significant correlation between any of the variables and vitamin A. CONCLUSION - There was no influence of the bariatric surgery technique used on serum vitamin A levels, on the visual function or on the ocular surface. Moreover, there was no correlation between serum levels of vitamin A and the visual function or the ocular surface changes.
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Affiliation(s)
| | - Lucio Vilar
- Hospital de Olhos de Pernambuco (HOPE), Recife, PE, Brasil
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Cruzat A, Qazi Y, Hamrah P. In Vivo Confocal Microscopy of Corneal Nerves in Health and Disease. Ocul Surf 2017; 15:15-47. [PMID: 27771327 PMCID: PMC5512932 DOI: 10.1016/j.jtos.2016.09.004] [Citation(s) in RCA: 218] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 09/19/2016] [Accepted: 09/25/2016] [Indexed: 12/20/2022]
Abstract
In vivo confocal microscopy (IVCM) is becoming an indispensable tool for studying corneal physiology and disease. Enabling the dissection of corneal architecture at a cellular level, this technique offers fast and noninvasive in vivo imaging of the cornea with images comparable to those of ex vivo histochemical techniques. Corneal nerves bear substantial relevance to clinicians and scientists alike, given their pivotal roles in regulation of corneal sensation, maintenance of epithelial integrity, as well as proliferation and promotion of wound healing. Thus, IVCM offers a unique method to study corneal nerve alterations in a myriad of conditions, such as ocular and systemic diseases and following corneal surgery, without altering the tissue microenvironment. Of particular interest has been the correlation of corneal subbasal nerves to their function, which has been studied in normal eyes, contact lens wearers, and patients with keratoconus, infectious keratitis, corneal dystrophies, and neurotrophic keratopathy. Longitudinal studies have applied IVCM to investigate the effects of corneal surgery on nerves, demonstrating their regenerative capacity. IVCM is increasingly important in the diagnosis and management of systemic conditions such as peripheral diabetic neuropathy and, more recently, in ocular diseases. In this review, we outline the principles and applications of IVCM in the study of corneal nerves in various ocular and systemic diseases.
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Affiliation(s)
- Andrea Cruzat
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Yureeda Qazi
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Pedram Hamrah
- Cornea & Refractive Surgery Service, Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, MA, USA; Boston Image Reading Center, Tufts Medical Center, Tufts University School of Medicine, Boston, MA; Cornea Service, New England Eye Center, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA.
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Dienes L, Kiss HJ, Perényi K, Nagy ZZ, Acosta MC, Gallar J, Kovács I. Corneal Sensitivity and Dry Eye Symptoms in Patients with Keratoconus. PLoS One 2015; 10:e0141621. [PMID: 26495846 PMCID: PMC4619831 DOI: 10.1371/journal.pone.0141621] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/09/2015] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate corneal sensitivity to selective mechanical, chemical, and thermal stimulation and to evaluate their relation to dry eye symptoms in patients with keratoconus. METHODS Corneal sensitivity to mechanical, chemical, and thermal thresholds were determined using a gas esthesiometer in 19 patients with keratoconus (KC group) and in 20 age-matched healthy subjects (control group). Tear film dynamics was assessed by Schirmer I test and by the non-invasive tear film breakup time (NI-BUT). All eyes were examined with a rotating Scheimpflug camera to assess keratoconus severity. RESULTS KC patients had significatly decreased tear secretion and significantly higher ocular surface disease index (OSDI) scores compared to controls (5.3±2.2 vs. 13.2±2.0 mm and 26.8±15.8 vs. 8.1±2.3; p<0.001). There was no significant difference in NI-BUT between the two groups (KC: 9.8±4.8 vs. control: 10.7±3.8; p>0.05). The mean threshold for selective mechanical (KC: 139.2±25.8 vs. control: 109.1±24.0 ml/min), chemical (KC: 39.4±3.9 vs. control: 35.2±1.9%CO2), heat (KC: 0.91±0.32 vs. control: 0.54±0.26 Δ°C) and cold (KC: 1.28±0.27 vs. control: 0.98±0.25 Δ°C) stimulation in the KC patients were significantly higher than in the control subjects (p<0.001, for all parameters). No correlation was found between age and mechanical, chemical, heat or cold thresholds in the patients with KC (p>0.05), whereas in the control subjects both mechanical (r = 0.52, p = 0.02), chemical (r = 0.47, p = 0.04), heat (r = 0.26, p = 0.04) and cold threshold (r = 0.40, p = 0.03) increased with age. In the KC group, neither corneal thickness nor tear flow, NI-BUT or OSDI correlated significantly with mechanical, chemical, heat or cold thresholds (p>0.05 for all variables). CONCLUSIONS Corneal sensitivity to different types of stimuli is decreased in patients with keratoconus independently of age and disease severity. The reduction of the sensory input from corneal nerves may contribute to the onset of unpleasant sensations in these patients and might lead to the impaired tear film dynamics.
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Affiliation(s)
- Lóránt Dienes
- Semmelweis University, Department of Ophthalmology, Budapest, Hungary
| | - Huba J. Kiss
- Semmelweis University, Department of Ophthalmology, Budapest, Hungary
| | - Kristóf Perényi
- Semmelweis University, Department of Ophthalmology, Budapest, Hungary
| | - Zoltán Z. Nagy
- Semmelweis University, Department of Ophthalmology, Budapest, Hungary
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC, San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC, San Juan de Alicante, Spain
| | - Illés Kovács
- Semmelweis University, Department of Ophthalmology, Budapest, Hungary
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Ramírez Fernández M, Hernández Quintela E, Naranjo Tackman R. Comparison of stromal corneal nerves between normal and keratoconus patients using confocal microscopy. ACTA ACUST UNITED AC 2014; 89:308-12. [PMID: 24951326 DOI: 10.1016/j.oftal.2014.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/17/2013] [Accepted: 02/24/2014] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To evaluate the differences in stromal corneal nerves between normal patients and keratoconus patients. MATERIAL AND METHODS A total of 140 eyes of 70 normal patients (group A) and 122 eyes of 87 keratoconus patients (group B) were examined with the confocal microscope, with a central scan of the total corneal thickness being taken. The morphology and thickness of the corneal stromal nerves were evaluated by using the Navis v. 3.5.0. software. Nerve thickness was obtained from the mean between the widest and the narrowest portions of each stromal nerve. RESULTS Corneal stromal nerves were observed as irregular linear hyper-reflective structures with wide and narrow portions in all cases. Mean corneal stromal nerves thickness in group A was 5.7±1.7 (range from 3.3 to 10.4 μ), mean corneal stromal nerves thickness in group B was 7.2±1.9 (range from 3.5 to 12.0 μ). There was a statistical significant difference (P<.05) in stromal corneal nerves thickness between group A and group B. CONCLUSION Stromal corneal nerves morphology was similar in both groups, but stromal nerves were thicker in keratoconus patients.
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Affiliation(s)
- M Ramírez Fernández
- Servicio de Córnea y Cirugía Refractiva, Asociación Para Evitar la Ceguera en México (APEC), Hospital Luis Sánchez Bulnes, Universidad Nacional Autónoma de México, México D.F., México.
| | - E Hernández Quintela
- Servicio de Córnea y Cirugía Refractiva, Asociación Para Evitar la Ceguera en México (APEC), Hospital Luis Sánchez Bulnes, Universidad Nacional Autónoma de México, México D.F., México
| | - R Naranjo Tackman
- Servicio de Córnea y Cirugía Refractiva, Asociación Para Evitar la Ceguera en México (APEC), Hospital Luis Sánchez Bulnes, Universidad Nacional Autónoma de México, México D.F., México
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Corneal sensitivity in keratoconus: a review of the literature. ScientificWorldJournal 2013; 2013:683090. [PMID: 24298221 PMCID: PMC3835775 DOI: 10.1155/2013/683090] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 09/22/2013] [Indexed: 11/18/2022] Open
Abstract
Corneal sensitivity has recently received much attention given the crucial role the corneal nerves play in maintaining normal corneal structure and function. An increased understanding of the corneal sensitivity and dry eye disease in keratoconus, including alterations of the conjunctival cells, may help explain the pathogenesis of this disorder. There is histological evidence of the involvement of corneal nerves in the pathology of keratoconus and it has been suggested that this plays a role in the pathophysiological features and progression of the disease. In this review, the impaired corneal sensitivity found on keratoconus and corneal sensitivity changes after cross-linking performed in patients with keratoconus are reported.
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Al-Aqaba MA, Otri AM, Fares U, Miri A, Dua HS. Organization of the regenerated nerves in human corneal grafts. Am J Ophthalmol 2012; 153:29-37.e4. [PMID: 21907318 DOI: 10.1016/j.ajo.2011.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Revised: 06/05/2011] [Accepted: 06/06/2011] [Indexed: 11/16/2022]
Abstract
PURPOSE To examine by histopathology the degree of nerve regeneration in human corneal grafts and to determine the anatomic organization and morphology of the regenerated nerves. DESIGN Experimental laboratory investigation. METHODS Twelve corneal grafts from 12 patients (7 men and 5 women) aged 34-93 (mean, 66.9 years) were included. The most common indication for regrafting was late endothelial failure. The mean duration of graft survival was 6.41 years (range, 1-14 years). The freshly obtained specimens with a narrow rim of host tissue incorporating the graft-host junction were subjected to the acetylcholinesterase method for the demonstration of corneal nerves. RESULTS Subbasal nerves were found in 75% and 25% of the grafts at the periphery and center, respectively. They were mostly originated from the host subbasal nerves. Regenerated stromal nerves were detected in 83% of the specimens; half of them showed extension into the center of the graft. A lack of the normal link between the subbasal and stromal nerves was observed and almost all of the regenerated stromal nerves were found to remain within the stroma and did not contribute to the epithelial innervation. CONCLUSIONS A persistent anatomic disorganization of the corneal nerves in human grafts was found even 14 years after surgery. This could explain the significant reduction of corneal sensation reported in previous studies.
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Affiliation(s)
- Mouhamed Ali Al-Aqaba
- School of Clinical Sciences, Division of Ophthalmology and Visual Sciences, University of Nottingham, United Kingdom
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