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Smirnov VM, Lasseaux E, Michaud V, Courdier C, Meunier I, Arveiler B, Defoort-Dhellemmes S. Crossed VEP asymmetry in a patient with AHR-linked infantile nystagmus and foveal hypoplasia. Doc Ophthalmol 2024:10.1007/s10633-024-09979-6. [PMID: 38922562 DOI: 10.1007/s10633-024-09979-6] [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: 12/13/2023] [Accepted: 06/05/2024] [Indexed: 06/27/2024]
Abstract
INTRODUCTION Infantile nystagmus and foveal hypoplasia associated with AHR gene defects is a newly recognized and rare disorder. Our aim was to present a patient with a novel biallelic AHR pathogenic variant with electrophysiological evidence of chiasmal misrouting. MATERIALS AND METHODS Complete ocular examination, fundus imaging, visual evoked potentials (VEP) and full-field electroretinography were performed at initial presentation. Genetic testing was performed by whole exome sequencing. RESULTS Female patient of 6 years old presented a reduced best corrected visual acuity, an infantile nystagmus and a grade III typical foveal hypoplasia without ocular hypopigmentation. A crossed asymmetry was discovered on pattern onset/offset VEP. Genetic testing put in evidence a novel homozygous variant in AHR: c.2242del, p. (Gln748Lysfs*5). During 11-years follow-up period, BCVA gradually improved. There was no evidence of retinal degeneration. CONCLUSION AHR gene defects could be associated with infantile nystagmus, foveal hypoplasia and chiasmal misrouting.
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Affiliation(s)
- Vasily M Smirnov
- Service d'Exploration de la Vision et de Neuro-Ophtalmologie, Hôpital Roger Salengro, CHU de Lille, 59000, Lille, France.
- Inserm, U1172-LilNCog-Lille Neuroscience & Cognition, CHU Lille, Univ. Lille, 59045, Lille, France.
| | - Eulalie Lasseaux
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
| | - Vincent Michaud
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
- Inserm U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | - Cécile Courdier
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, Sensgene Care Network, ERN-EYE Network, Montpellier University Hospital, University of Montpellier, 34295, Montpellier, France
- Institute for Neurosciences of Montpellier (INM), INSERM, University of Montpellier, 34295, Montpellier, France
| | - Benoit Arveiler
- Service de Génétique Médicale, CHU de Bordeaux, Bordeaux, France
- Inserm U1211, Maladies Rares, Génétique et Métabolisme, Université de Bordeaux, Bordeaux, France
| | - Sabine Defoort-Dhellemmes
- Service d'Exploration de la Vision et de Neuro-Ophtalmologie, Hôpital Roger Salengro, CHU de Lille, 59000, Lille, France
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A clinical and electrophysiological case study of a child with a novel frame shift mutation in the CACNA1F and missense variation of RIMS1 genes. Doc Ophthalmol 2022; 145:163-174. [PMID: 35947237 DOI: 10.1007/s10633-022-09892-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 07/07/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE The purpose of this paper is to present a case study illustrating the importance of electrophysiological investigation in the diagnosis and serial monitoring of isolated congenital nystagmus. RESULTS Serial electophysiological monitoring was undertaken in the male proband over a 9-year period commencing with initial assessment at 12 weeks of age: Skin electroretinograms (sERGs) were initially absent but subsequently revealed low-amplitude responses, electronegative morphologies and notched flicker responses suggestive of incomplete congenital stationary night blindness (CSNB2), but with an absent dark-adapted rod-specific response, while flash visual evoked potentials (fVEPs) demonstrated persistent crossed asymmetry, typical of albinoid misrouting of the optic nerves. Molecular investigation confirmed a novel hemizygous frame shift mutation in the CACNA1F gene, considered to be pathogenic and causative of X-linked CSNB2; additionally, a novel heterozygous missense variation in one copy of the RIMS1 gene was identified, pathogenic mutations of which underpin late-onset autosomal dominant cone-rod dystrophy (type 7). Segregation studies confirmed maternal inheritance of both mutations in the clinically asymptomatic mother in whom depressed rod-specific responses were confirmed on sERG. The child's visual acuity has remained stable as have the sERGs which have been verified by recordings using scleral electrodes. CONCLUSIONS The importance of recording ERGs as part of evaluating infants who present with nystagmus, even with a normal fundus appearance, is supported. Further, sERGs were able to distinguish an apparent variant of CSNB2 and could give consistent results over many years. FVEP results add to the evidence that albinoid misrouting of the optic nerves may occur in cases of CSNB2. ERGs and fVEPs can provide valuable information in discriminating the relative diagnostic importance of multiple genetic abnormalities.
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Bhate M, Lalwani S, Chakrabarti S. Phenotypic variations in ocular features among siblings with oculocutaneous albinism. Indian J Ophthalmol 2022; 70:2511-2515. [PMID: 35791147 PMCID: PMC9426174 DOI: 10.4103/ijo.ijo_1025_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Purpose: To assess the clinical profiles, presenting ocular features, and variations in the phenotypic features in siblings with oculocutaneous albinism (OCA). Methods: Electronic medical records of consecutive siblings diagnosed with albinism from January 2016 to December 2020 were reviewed to identify the affected siblings. The variations in their phenotypic characteristics were studied. Results: Significant variations were observed in the clinical features between the siblings (n = 42). A difference of >2 lines in visual acuity was observed in 50% (n = 21) of the sibling pairs. Compound hyperopic astigmatism was the commonest refractive error. The refractive status was different in 80.95% (n = 34) pairs. Although individually strabismus and abnormal head posture were observed in one-third and one-fourth of individual children, respectively, both siblings with similar strabismus were seen in only 16.67% (n = 7) and with a similar abnormal head posture in 13.33% (n = 5). Nystagmus was the most consistent finding across these siblings with a similar nature of horizontal jerk or pendular in 65% of sibling pairs. Conclusion: This study observed significant variations in phenotypic presentations among siblings with OCA. Such differences in clinical manifestations and severity would be helpful in appropriate counseling of these families as the need for rehabilitation services is likely to vary across siblings.
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Affiliation(s)
- Manjushree Bhate
- Strabismus, Pediatric and Neuro-Ophthalmology, Jasti V. Ramanamma Children's Eye Care Centre, L.V. Prasad Eye Institute, Hyderabad, Telangana, India
| | - Sakshi Lalwani
- Strabismus, Pediatric and Neuro-Ophthalmology, Jasti V. Ramanamma Children's Eye Care Centre, L.V. Prasad Eye Institute, Hyderabad, Telangana, India
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Sather ΙΙΙ R, Thompson D, Ihinger J, Montezuma SR. Septo-optic dysplasia presenting with nystagmus, pseudo-disc edema, and fovea hypoplasia. Ophthalmic Genet 2022; 43:522-529. [DOI: 10.1080/13816810.2022.2039720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Richard Sather ΙΙΙ
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Dorothy Thompson
- Tony Kriss Visual Electrophysiology Unit, Great Ormond Hospital for Children, London, UK
| | - Jacqueline Ihinger
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sandra R. Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA
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Handley SE, Šuštar M, Tekavčič Pompe M. What can visual electrophysiology tell about possible visual-field defects in paediatric patients. Eye (Lond) 2021; 35:2354-2373. [PMID: 34272512 PMCID: PMC8377065 DOI: 10.1038/s41433-021-01680-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/21/2021] [Accepted: 06/29/2021] [Indexed: 02/06/2023] Open
Abstract
Recognising a potential visual-field (VF) defect in paediatric patients might be challenging, especially in children before the age of 5 years and those with developmental delay or intellectual disability. Visual electrophysiological testing is an objective and non-invasive technique for evaluation of visual function in paediatric patients, which can characterise the location of dysfunction and differentiate between disorders of the retina, optic nerve and visual pathway. The recording of electroretinography (ERG) and visual-evoked potentials (VEP) is possible from early days of life and requires no subjective input from the patient. As the origins of ERG and VEP tests are known, the pattern of electrophysiological changes can provide information about the VF of a child unable to perform accurate perimetry. This review summarises previously published electrophysiological findings in several common types of VF defects that can be found in paediatric patients (generalised VF defect, peripheral VF loss, central scotoma, bi-temporal hemianopia, altitudinal VF defect, quadrantanopia and homonymous hemianopia). It also shares experience on using electrophysiological testing as additional functional evidence to other tests in the clinical challenge of diagnosing or excluding VF defects in complex paediatric patients. Each type of VF defect is illustrated with one or two clinical cases.
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Affiliation(s)
- Siân E. Handley
- grid.83440.3b0000000121901201UCL Great Ormond Street Institute of Child Health, London, UK ,grid.424537.30000 0004 5902 9895Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children NHS foundation trust, London, UK
| | - Maja Šuštar
- grid.29524.380000 0004 0571 7705Unit for Visual Electrophysiology and Paediatric Ophthalmology Department, Eye Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Manca Tekavčič Pompe
- grid.29524.380000 0004 0571 7705Unit for Visual Electrophysiology and Paediatric Ophthalmology Department, Eye Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
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Case report: Unilateral optic nerve aplasia and developmental hemi-chiasmal dysplasia with VEP misrouting. Doc Ophthalmol 2020; 142:247-255. [PMID: 32852652 PMCID: PMC7943516 DOI: 10.1007/s10633-020-09788-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/07/2020] [Indexed: 12/02/2022]
Abstract
Purpose To describe the trans-occipital asymmetries of pattern and flash visual evoked potentials (VEPs), in an infant with MRI findings of unilateral optic nerve aplasia and hemi-chiasm dysplasia. Methods A child with suspected left cystic microphthalmia, left microcornea, left unilateral optic nerve aplasia, and hemi-chiasm underwent a multi-channel VEP assessment with pattern reversal, pattern onset, and flash stimulation at the age of 16 weeks. Results There was no VEP evidence of any post-retinal visual pathway activation from left eye with optic nerve aplasia. The VEP trans-occipital distribution from the functional right eye was skewed markedly across the midline, in keeping with significant misrouting of optic nerve fibres at the chiasm. This was supported by the anatomical trajectory of the optic chiasm and tracts seen on MRI. Conclusion This infant has chiasmal misrouting in association with unilateral optic nerve aplasia and unilateral microphthalmos. Chiasmal misrouting has not been found in patients with microphthalmos or anophthalmos, but has been reported after early eye loss in animal models. Our findings contribute to our understanding of the discrepancy between the visual pathway physiology of human unilateral microphthalmia and animal models.
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Campbell P, Ellingford JM, Parry NRA, Fletcher T, Ramsden SC, Gale T, Hall G, Smith K, Kasperaviciute D, Thomas E, Lloyd IC, Douzgou S, Clayton-Smith J, Biswas S, Ashworth JL, Black GCM, Sergouniotis PI. Clinical and genetic variability in children with partial albinism. Sci Rep 2019; 9:16576. [PMID: 31719542 PMCID: PMC6851142 DOI: 10.1038/s41598-019-51768-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/30/2019] [Indexed: 12/20/2022] Open
Abstract
Individuals who have ocular features of albinism and skin pigmentation in keeping with their familial background present a considerable diagnostic challenge. Timely diagnosis through genomic testing can help avert diagnostic odysseys and facilitates accurate genetic counselling and tailored specialist management. Here, we report the clinical and gene panel testing findings in 12 children with presumed ocular albinism. A definitive molecular diagnosis was made in 8/12 probands (67%) and a possible molecular diagnosis was identified in a further 3/12 probands (25%). TYR was the most commonly mutated gene in this cohort (75% of patients, 9/12). A disease-causing TYR haplotype comprised of two common, functional polymorphisms, TYR c.[575 C > A;1205 G > A] p.[(Ser192Tyr);(Arg402Gln)], was found to be particularly prevalent. One participant had GPR143-associated X-linked ocular albinism and another proband had biallelic variants in SLC38A8, a glutamine transporter gene associated with foveal hypoplasia and optic nerve misrouting without pigmentation defects. Intriguingly, 2/12 individuals had a single, rare, likely pathogenic variant in each of TYR and OCA2 - a significant enrichment compared to a control cohort of 4046 individuals from the 100,000 genomes project pilot dataset. Overall, our findings highlight that panel-based genetic testing is a clinically useful test with a high diagnostic yield in children with partial/ocular albinism.
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Affiliation(s)
- Patrick Campbell
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Jamie M Ellingford
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Neil R A Parry
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK
| | - Tracy Fletcher
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Simon C Ramsden
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Theodora Gale
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Georgina Hall
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | | | | | | | - I Chris Lloyd
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Sofia Douzgou
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Jill Clayton-Smith
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Susmito Biswas
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK
| | - Jane L Ashworth
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK
| | - Graeme C M Black
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
| | - Panagiotis I Sergouniotis
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK.
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Kruijt CC, de Wit GC, Talsma HE, Schalij-Delfos NE, van Genderen MM. The Detection Of Misrouting In Albinism: Evaluation of Different VEP Procedures in a Heterogeneous Cohort. ACTA ACUST UNITED AC 2019; 60:3963-3969. [DOI: 10.1167/iovs.19-27364] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Charlotte C. Kruijt
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | - Gerard C. de Wit
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
| | - Herman E. Talsma
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
| | | | - Maria M. van Genderen
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands
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Occipital Petalia and Albinism: A Study of Interhemispheric VEP Asymmetries in Albinism with No Nystagmus. J Clin Med 2019; 8:jcm8060802. [PMID: 31195712 PMCID: PMC6617331 DOI: 10.3390/jcm8060802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 01/31/2023] Open
Abstract
The purpose of this study was to assess chiasmal misrouting in a cohort of children with albinism with no nystagmus using hemifield visual evoked potentials (VEP) measures. Methods: Monocular VEPs were recorded and analyzed from three electrodes (O1, Oz, and O2 referred to Fz) from 16 children with albinism without nystagmus. Pattern reversal (full field and hemifield stimulation), full field pattern appearance and flash stimuli were used to evoke VEPs for each eye. Results: The amplitude of the pattern reversal VEPs to stimulation of the hemifield corresponding to the crossing pathways were as expected significantly larger than those to the non-crossing in each eye ((right eye p = 0.000004), (left eye p = 0.001)). Pattern reversal VEPs recorded from the left hemisphere were also larger than those from the right and most evident when comparing the crossing pathways of each eye (p = 0.004). Conclusions: This study has demonstrated electrophysiological differences in visual pathway function of the left and right hemisphere in subjects with albinism like that previously described in controls. Nasal field stimulation activated crossing and non-crossing pathways in patients with albinism and as a result, nasal hemifield VEPs in albinism are less lateralized compared to what is found in normal subjects.
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Richards MD, Wong A. Infantile nystagmus syndrome: clinical characteristics, current theories of pathogenesis, diagnosis, and management. Can J Ophthalmol 2016; 50:400-8. [PMID: 26651297 DOI: 10.1016/j.jcjo.2015.07.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 07/12/2015] [Accepted: 07/22/2015] [Indexed: 11/25/2022]
Abstract
Infantile nystagmus syndrome (INS) is an important clinical diagnosis because it is a common presenting sign of many ocular, neurologic, and systemic diseases. Although INS has been studied for more than a century, its diagnosis and treatment remains a challenge to clinicians because of its varied manifestations and multiple associations, and its pathogenesis continues to rouse considerable scientific debate. Fueled by these challenges, recent basic research and clinical investigations have provided new insights into INS. New genetic discoveries and technological advances in ocular imaging have refined our understanding of INS subtypes and offer new diagnostic possibilities. Unexpected surgical outcomes have led to new understanding of its pathogenesis based on novel hypothesized pathways of ocular motor control. Comparative studies on nonhuman visual systems have also informed models of the neural substrate of INS in humans. This review brings together the classic profile of this disorder with recent research to provide an update on the clinical features of INS, an overview of the current theories on how and why INS develops, and a practical approach to the diagnosis and management of INS.
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Affiliation(s)
- Michael D Richards
- Department of Ophthalmology & Vision Sciences, The Hospital for Sick Children; Department of Ophthalmology & Vision Sciences, University of Toronto, Toronto, Ont..
| | - Agnes Wong
- Department of Ophthalmology & Vision Sciences, The Hospital for Sick Children; Department of Ophthalmology & Vision Sciences, University of Toronto, Toronto, Ont
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12
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Abstract
PURPOSE OF REVIEW To describe the entity of Lyonization in ocular eye diseases, along with its clinical and counseling implications. RECENT FINDINGS Several X-linked ocular diseases such as choroideremia, X-linked retinitis pigmentosa, and X-linked ocular albinism may have signs of Lyonization on ocular examination and diagnostic testing. These findings may aid in the proper diagnosis of ocular disease in both female carriers and their affected male relatives. SUMMARY Manifestations of Lyonization in the eye may help in the diagnosis of X-linked ocular diseases which may lead to accurate diagnosis, appropriate molecular genetic testing and genetic counseling.
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VEP characteristics in children with achiasmia, in comparison to albino and healthy children. Doc Ophthalmol 2012; 124:109-23. [DOI: 10.1007/s10633-012-9315-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 01/27/2012] [Indexed: 10/28/2022]
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Abstract
Albinism is a group of disorders characterized principally by its ophthalmic features with or without systemic manifestations. Persons with albinism manifest a wide variety of phenotypes and limited number of genotypes. Modern molecular genetics has encouraged a new classification and understanding of the subtypes of these disorders. In addition to the ocular and systemic manifestations, ophthalmologists must be familiar with the specific visual needs and psychological challenges of these individuals as well as those of their families.
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Affiliation(s)
- Alex V Levin
- Wills Eye Institute, Pediatric Ophthalmology and Ocular Genetics, Philadelphia, Pennsylvania 19107, USA.
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Li X, Lu Y, Li L, Chai X, Ren Q. Multi-channel visual evoked potential as an ancillary tool to diagnose intraorbital optic nerve lesions. Vet Ophthalmol 2010; 13:131-5. [PMID: 20447034 DOI: 10.1111/j.1463-5224.2010.00769.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multi-channel visual evoked potential (MVEP) recording method was used to assist in diagnosing a 4-month-old Chinese Albino rabbit with an intraorbital mass. Subcutaneous MVEP of its both eyes were recorded simultaneously using 16 electrodes (4 x 4) multi-channel array. Analysis of the cortical potential landscapes (CPL) showed that the conduction function of right eye was remarkably impaired in terms of decreased amplitudes and prolonged latencies. Specific side-dominant distribution asymmetry of the decreased MVEP amplitudes indicated that the temporal side of the optic nerve (ON) was severely involved. Overall prolonged latencies of the CPL without side differences suggested that the functional impairment could have been caused by the mechanical compression exerted by an intraorbital mass. Surgical removal procedures confirmed that the mass was located temporally to the ON. Pathological examination provided a final diagnosis of a giant polycystic mucocele. Beyond its significance as a standard tool to assess functional changes of the visual pathway, MVEP recordings might assist locating intraorbital lesions that involve the ON by careful analysis of abnormal CPLs.
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Affiliation(s)
- Xiaoliang Li
- Department of Biomedical Engineering, School of Life Science and Technology, Shanghai Jiao Tong University, 800# Dongchuan Rd, Shanghai, 200240, China
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Kumar A, Gottlob I. Diagnosis of idiopathic infantile nystagmus and ocular albinism: a clinical challenge. EXPERT REVIEW OF OPHTHALMOLOGY 2009. [DOI: 10.1586/eop.09.31] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
A child is referred because of reduced visual acuity in one or both eyes. This scenario is equally familiar to the ophthalmologist, orthoptist, electrophysiologist, and imaging specialist. Each specialty is looking for markers for disease and / or dysfunction to aid in diagnosis. This paper describes three cases in which strabismic, anisometropic, or nonorganic amblyopia was suspected initially, but proved not to be the underlying cause of reduced vision. The role of visual electrophysiology in assessing retinal and visual pathway function in each case is described and emphasized. To determine the pathologic cause for vision loss these specific scenarios required effective interdisciplinary collaboration and communication. The combined interdisciplinary approach often leads to a diagnosis earlier in the disease process, thus facilitating current or future treatment and / or recovery. As advancing technologies allow more detailed understanding of both function and structure, questions are raised regarding the underlying pathophysiology of eye disease including amblyopia.
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Affiliation(s)
- Carole M Panton
- From the Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
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Hoffmann MB, Schmidtborn LC, Morland AB. Abnormale Repräsentationen im visuellen Kortex von Albinismus-Patienten. Ophthalmologe 2007; 104:666-73. [PMID: 17661055 DOI: 10.1007/s00347-007-1589-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A characteristic feature of patients with albinism is the misrouting of the optic nerves, which causes the visual cortex to receive an abnormal input. This report details how the detection of misrouting using visual evoked potentials assists the clinical diagnosis of albinism. Further, it shows how the projection abnormality observed in patients with albinism provides a model for investigating the self-organisation of the human visual cortex. This is highlighted by recent findings that were obtained using functional magnetic resonance imaging, visual evoked potentials, and static visual field perimetry.
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Affiliation(s)
- M B Hoffmann
- Sektion für klinische und experimentelle Sinnesphysiologie, Universitätsaugenklinik Magdeburg, Leipziger Strasse 44, 39120, Magdeburg, Deutschland.
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Timms C, Thompson D, Russell-Eggitt I, Clement R. Saccadic instabilities in albinism without nystagmus. Exp Brain Res 2006; 175:45-9. [PMID: 16718432 DOI: 10.1007/s00221-006-0522-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Accepted: 04/24/2006] [Indexed: 11/25/2022]
Abstract
Albinism effects a surprising manipulation of the visual pathway in which some of the normally uncrossed axons of the temporal retina instead cross at the chiasm. An expected consequence of this misrouting is that subjects with albinism will have difficulty in specifying the targets of saccades. Usually albinos have nystagmus so the stability of their saccadic eye movements is not readily accessible, but some albinos do not have nystagmus. In these subjects it was found that they had frequent saccadic intrusions, the sizes of which were correlated with velocities of steady drifts in fixations (r = 0.802, P < 0.05). An explanation for the correlation between the amplitudes of the intrusions and the velocities of the drifts is that it is due to a common failure in the development of a saccadic system which is responsible for converting a given retinal displacement into a matching eye movement, with the extent of the failure reflecting the severity of the misrouting.
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Affiliation(s)
- Chris Timms
- Department of Ophthalmology, Great Ormond Street Hospital for Children, London, WC1N 3JH, UK
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Ung T, Allen LE, Moore AT, Trump D, Zito I, Hardcastle AJ, Yates J, Bradshaw K. Is Optic Nerve Fibre Mis-Routing a Feature of Congenital Stationary Night Blindness? Doc Ophthalmol 2006; 111:169-78. [PMID: 16523234 DOI: 10.1007/s10633-005-5503-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2005] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine whether patients with congenital stationary night blindness (CSNB) have electrophysiological evidence of optic nerve fibre mis-routing similar to that found in patients with ocular albinism (OA). METHOD We recorded the Pattern Onset VEP using a protocol optimised to detect mis-routing of optic nerve fibres in older children and adults. We tested 20 patients (age 15-69 yrs) with X-linked or autosomal recessive CSNB, 14 patients (age 9-56 yrs) with OA and 13 normally pigmented volunteers (age 21-66 yrs). We measured the amplitude and latency of the CI component at the occipital midline and over left and right occipital hemispheres. We also assessed the computed inter-hemispheric "difference" signal. Subjects with CSNB were classified as having the "complete" or "incomplete" phenotype on the basis of their ERG characteristics. Members of X-linked CSNB pedigrees underwent mutation screening of the NYX and CACNA1F genes. RESULTS CI was significantly smaller over the ipsilateral hemisphere and more prominent over the contralateral hemisphere in OA patients compared with both controls and CSNB patients. In CSNB patients CI response amplitudes were not significantly different from controls but peak latency was prolonged at all three electrodes compared with controls. The inter-hemispheric "difference" signal was abnormal for the OA group but not for the CSNB group. Contralateral dominance of CI could be identified in the majority of OA patients and the "difference" signal was opposite in polarity for left compared with right eye stimulation in every patient in this group. Only 3 of 20 patients with CSNB showed significant inter-hemispheric asymmetry similar to that seen in the OA patients. All 3 CSNB patients with evidence for optic nerve fibre mis-routing had X-linked pedigrees: 2 had an identified mutation in the NYX gene but no mutation in either the NYX or CACNA1F genes was identified in the third. VEP evidence of optic nerve fibre mis-routing was present in 3 of the 11 subjects with "complete" phenotype and none of the 9 patients with "incomplete" phenotype CSNB. CONCLUSION Mis-routing of optic nerve fibres does occur in CSNB but we found evidence of it in only 15% of our patients.
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Affiliation(s)
- T Ung
- Ophthalmology Department, Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK
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Sami DA, Saunders D, Thompson DA, Russell-Eggitt IM, Nischal KK, Jeffrey G, Jeffery G, Dattani M, Clement RA, Liasis A, Liassis A, Taylor DS. The achiasmia spectrum: congenitally reduced chiasmal decussation. Br J Ophthalmol 2005; 89:1311-7. [PMID: 16170123 PMCID: PMC1772901 DOI: 10.1136/bjo.2005.068171] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To describe the clinical spectrum of achiasmia, a congenital disorder of reduced relative decussation at the optic chiasm. METHODS A retrospective case note and patient review of nine children (four boys). Achiasmia was defined by the combination of a characteristic asymmetry of the monocular visual evoked potential (VEP) response to flash and neuroimaging showing reduced chiasmal size. RESULTS Three of the children had an associated skull base encephalocele with agenesis of the corpus callosum. In two patients achiasmia was associated with septo-optic dysplasia. Three patients had no neuroimaging abnormalities other than reduced chiasmal size and have no known pituitary dysfunction. One child had multiple physical deformities but the only brain imaging abnormality was reduced chiasmal size. CONCLUSIONS Some children with disorders of midline central nervous system development, including septo-optic dysplasia and skull base encephaloceles, have congenitally reduced chiasmal decussation. Reduced relative decussation may co-exist with overall chiasmal hypoplasia. Children with an apparently isolated chiasmal decussation deficit may have other subtle neurological findings, but our clinical impression is that most of these children function well.
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Affiliation(s)
- D A Sami
- Visual Sciences Unit, Institute of Child Health University College, London WC1N 1EH, UK
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Ohde H, Shinoda K, Nishiyama T, Kado H, Haruta Y, Mashima Y, Oguchi Y. New method for detecting misrouted retinofugal fibers in humans with albinism by magnetoencephalography. Vision Res 2004; 44:1033-8. [PMID: 15031097 DOI: 10.1016/j.visres.2003.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Revised: 12/09/2003] [Indexed: 11/24/2022]
Abstract
In humans with albinism, a large percentage of the ganglion cell axons from the temporal retina decussate abnormally in the chiasm and synapse in the contralateral LGN. The aim of this study was to determine whether the misrouting of the optic fibers can be detected by magnetoencephalography (MEG). Visually evoked magnetic fields (VEFs) were recorded from three patients with albinism. After monocular stimulation, the isofield contour maps of the VEFs showed a single current dipole pattern over the contralateral hemisphere in patients with albinism. These results clearly illustrated the reduced uncrossed retinofugal pathway of patients with albinism.
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Affiliation(s)
- Hisao Ohde
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan.
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Dorey SE, Neveu MM, Burton LC, Sloper JJ, Holder GE. The clinical features of albinism and their correlation with visual evoked potentials. Br J Ophthalmol 2003; 87:767-72. [PMID: 12770978 PMCID: PMC1771702 DOI: 10.1136/bjo.87.6.767] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2002] [Indexed: 01/23/2023]
Abstract
AIM To investigate the relation between the clinical and electrophysiological abnormalities of patients undergoing visual evoked potential investigation for albinism. METHODS 40 subjects with a probable or possible clinical diagnosis of albinism underwent pattern appearance and/or flash visual evoked potential (VEP) examination. The VEP findings are correlated with the clinical features of albinism determined by clinical examination and orthoptic assessment. RESULTS The majority of patients with clinical evidence of albinism showed a contralateral predominance in the VEPs. There was close correlation between the clinical signs of albinism and the degree of contralateral VEP predominance. This manifested as an interhemispheric latency asymmetry to monocular pattern appearance stimulation but amplitude asymmetry to flash stimulation. The strongest correlation for pattern appearance interhemispheric latency difference was with foveal hypoplasia (rho = 0.58; p = 0.0003) followed by nystagmus (rho = 0.48; p = 0.0027) and iris transillumination (rho = 0.33; p = 0.039). The VEP abnormalities were of greater magnitude in those patients with most features of albinism. Several patients with apparently mild disorders of ocular pigmentation had small but significantly abnormal VEP latency asymmetries. CONCLUSION There is a strong association between the magnitude of the interhemispheric latency asymmetry of the pattern appearance VEP, and of amplitude asymmetry of the flash VEP, with the clinical signs of albinism. The data are consistent with a spectrum of abnormalities in albinism involving both clinical expression and electrophysiological misrouting, which is wider than previously recognised.
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Affiliation(s)
- S E Dorey
- Strabismus and Paediatric Service, Moorfields Eye Hospital, City Road, London EC1V 2PD, UK
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Pott JWR, Jansonius NM, Kooijman AC. Chiasmal coefficient of flash and pattern visual evoked potentials for detection of chiasmal misrouting in albinism. Doc Ophthalmol 2003; 106:137-43. [PMID: 12678278 DOI: 10.1023/a:1022526409674] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The diagnosis of albinism can be confirmed by electrophysiological examination, when chiasmal misrouting can be demonstrated. The present study describes a quantitative analysis method for this purpose. A chiasmal coefficient (CC) was calculated by correlating the differential potential over left and right hemisphere, when stimulating left versus right eye. This CC will be negative in albinism and positive in normal individuals. VEPs were recorded in 20 control subjects, four children with congenital motor nystagmus and six children with albinism. In up to 25% of the controls the CC was negative, when using flash VEP. However, with pattern VEP all had a positive CC. All children with albinism had a negative CC. Three of the four patients with congenital motor nystagmus had a positive CC, and one child had a small negative value with flash stimulation. In conclusion, determination of CC is a valuable and objective analysis method for electrophysiological determination of chiasmal misrouting. The method is relatively simple and only needs two electrode tracings. One should be aware of false-positive results when using flash stimulation. Whenever possible pattern stimulation should be used.
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Affiliation(s)
- J W R Pott
- Department of Ophthalmology, University Hospital Groningen, Groningen, The Netherlands.
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Jansonius NM, van der Vliet TM, Cornelissen FW, Pott JW, Kooijman AC. A girl without a chiasm: electrophysiologic and MRI evidence for the absence of crossing optic nerve fibers in a girl with a congenital nystagmus. J Neuroophthalmol 2001; 21:26-9. [PMID: 11315977 DOI: 10.1097/00041327-200103000-00007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An otherwise healthy 15-year-old girl with a congenital nystagmus was evaluated at our department using visual evoked potential recording and magnetic resonance imaging. She appears to have the unique isolated inborn absence of the optic chiasm, described only once before in two unrelated girls. Unlike these previously described cases, our patient does not seem to display a see-saw nystagmus.
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Affiliation(s)
- N M Jansonius
- Department of Ophthalmology, University of Groningen, The Netherlands.
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