Anthony T Moore

Great Ormond Street Hospital for Children NHS Foundation Trust, Londinium, England, United Kingdom

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Publications (166)898.41 Total impact

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    ABSTRACT: Retinitis pigmentosa (RP) is a group of genetically and clinically heterogeneous inherited degenerative retinopathies caused by abnormalities of photoreceptors or retinal pigment epithelium in the retina leading to progressive sight loss. Rhodopsin is the prototypical G-protein-coupled receptor located in the vertebrate retina and responsible for dim light vision. Here, novel M39R and N55K variants were identified as causing an intriguing sector phenotype of RP in affected patients, with selective degeneration in the inferior retina. In order to gain insights into the molecular aspects associated with this sector RP phenotype, whose molecular mechanism remains elusive, the mutations were constructed by site-directed mutagenesis, expressed in heterologous systems and studied by biochemical, spectroscopic and functional assays. M39R and N55K opsins had variable degrees of chromophore regeneration when compared to WT opsin, but showed no gross structural misfolding or altered trafficking. M39R showed a faster rate for transducin activation than WT rhodopsin with a faster metarhodopsinII decay, whereas N55K presented a reduced activation rate and an altered photobleaching pattern. N55K also showed an altered retinal release from the opsin binding pocket upon light exposure, affecting its optimal functional response. Our data suggest that these sector RP mutations cause different protein phenotypes which may be related to their different clinical progression. Overall, these findings illuminate the molecular mechanisms of sector RP associated with rhodopsin mutations.
    The Journal of biological chemistry. 10/2014;
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    ABSTRACT: Purpose To describe the clinical and molecular characteristics of patients with childhood-onset Stargardt disease (STGD). Design Retrospective case series. Participants Forty-two patients who were diagnosed with STGD in childhood at a single institution between January 2001 and January 2012. Methods A detailed history and a comprehensive ophthalmic examination were undertaken, including color fundus photography, autofluorescence imaging, spectral-domain optical coherence tomography (SD-OCT), and pattern and full-field electroretinograms. The entire coding region and splice sites of ABCA4 were screened using a next-generation, sequencing-based strategy. The molecular genetic findings of childhood-onset STGD patients were compared with those of adult-onset patients. Main Outcome Measures Clinical, imaging, electrophysiologic, and molecular genetic findings. Results The median ages of onset and the median age at baseline examination were 8.5 (range, 3–16) and 12.0 years (range, 7-16), respectively. The median baseline logarithm of the minimum angle of resolution visual acuity was 0.74. At baseline, 26 of 39 patients (67%) with available photographs had macular atrophy with macular/peripheral flecks; 11 (28%) had macular atrophy without flecks; 1 (2.5%) had numerous flecks without macular atrophy; and 1 (2.5%) had a normal fundus appearance. Flecks were not identified at baseline in 12 patients (31%). SD-OCT detected foveal outer retinal disruption in all 21 patients with available images. Electrophysiologic assessment demonstrated retinal dysfunction confined to the macula in 9 patients (36%), macular and generalized cone dysfunction in 1 subject (4%), and macular and generalized cone and rod dysfunction in 15 individuals (60%). At least 1 disease-causing ABCA4 variant was identified in 38 patients (90%), including 13 novel variants; ≥2 variants were identified in 34 patients (81%). Patients with childhood-onset STGD more frequently harbored 2 deleterious variants (18% vs 5%) compared with patients with adult-onset STGD. Conclusions Childhood-onset STGD is associated with severe visual loss, early morphologic changes, and often generalized retinal dysfunction, despite often having less severe fundus abnormalities on examination. One third of children do not have flecks at presentation. The relatively high proportion of deleterious ABCA4 variants supports the hypothesis that earlier onset disease is often owing to more severe variants in ABCA4 than those found in adult-onset disease.
    Ophthalmology 10/2014; · 5.56 Impact Factor
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    ABSTRACT: Purpose: Gene therapy trials for inherited photoreceptor disorders are planned. Anatomical metrics to select the best candidates and outcomes are needed. Adaptive optics (AO) imaging enables visualization of photoreceptor structure, though analytical tools are lacking. Here we present criteria to assess residual photoreceptor integrity in achromatopsia (ACHM). Methods: Two AOSLOs, at the Medical College of Wisconsin and Moorfields Eye Hospital, were used to image the photoreceptor mosaic of eleven subjects with ACHM and seven age-matched controls. Images were obtained, processed and montaged using previously described methods. Cone density and reflectivity were quantified to assess residual cone photoreceptor structure. Results: All subjects with ACHM had reduced numbers of cone photoreceptors, albeit to a variable degree. In addition, the relative cone reflectivity varied greatly. Interestingly, subjects with GNAT2-associated ACHM had the greatest number of residual cones and the reflectivity of those cones was significantly greater than that of the cones in the subjects with CNGA3/B3-associated ACHM. Conclusions: We present cone reflectivity as a metric that can be used to characterize cone structure in ACHM. This method may be applicable to subjects with other cone disorders. In ACHM, we hypothesize that cone numerousity (and/or density) combined with cone reflectivity could be used to gauge the therapeutic potential. As gene replacement would not add cones, reflectivity could be a more powerful AO-metric for monitoring the cellular response to treatment and could provide a more immediate indicator of efficacy than behavioral measures, which may take longer to change.
    Investigative ophthalmology & visual science. 10/2014;
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    ABSTRACT: Purpose: To present a detailed phenotypic and molecular study of a series of 18 patients from 11 families with retinal dystrophies consequent on mutations in the cone-rod homeobox (CRX) gene and to report a novel phenotype. Methods: Families were ascertained from a tertiary clinic in the UK and enrolled in to retinal dystrophy studies investigating the phenotype and molecular basis of inherited retinal disease. Eleven patients were ascertained from the study cohorts and a further 7 from investigation of affected relatives. Detailed phenotyping included electrodiagnostic testing and retinal imaging. Bi-directional Sanger sequencing of all exons and intron-exon boundaries of CRX was performed on all 18 reported patients and segregation confirmed in available relatives. Results: Based on clinical characteristics and electrophysiology, 4 patients had Leber congenital amaurosis (LCA), 2 rod cone dystrophy (RCD), 5 cone rod dystrophy (CORD), 1 cone dystrophy (COD) and 6 macular dystrophy with different phenotypes observed within 4 of the 11 families. The macular dystrophy patients presented between 35-50 years old and had visual acuities at last review ranging from 0.2 to 1.5 logMAR (20/32 to 20/630 Snellen). All 18 patients were heterozygous for a mutation in CRX with 7 novel mutations identified. There was no evident association between age of onset and position or type of CRX mutation. De novo mutations were confirmed in 3 patients. Conclusions: Mutations in CRX demonstrate significant phenotypic heterogeneity both between and within pedigrees. A novel, adult onset, macular dystrophy phenotype is characterized, further extending our knowledge of the etiology of dominant macular dystrophies.
    Investigative ophthalmology & visual science. 09/2014;
  • Edited by Puech Bernard; De Laey Jean-Jacques; Holder Graham, 09/2014; Springer, 2014. eBook ISBN 978-3-540-69466-3.., ISBN: 978-3-540-69466-3.
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    ABSTRACT: Purpose: To describe the dark-adaptation (DA) functions in subjects with molecularly proven achromatopsia (ACHM) using refined testing conditions with a view to guiding assessment in forthcoming gene therapy trials. Methods: The DA functions of 9 subjects with ACHM were measured and compared to those of normal observers. The size and retinal location of the stimuli used to measure DA sensitivities were varied in four distinct testing condition sets, and the effect of altering these parameters assessed. Results: In three of the four testing condition sets, achromats had significantly higher mean final thresholds than normal observers, whereas in the fourth condition set they did not. A larger, more central stimulus revealed the greatest difference between the final DA thresholds of achromat and normal subjects, and also demonstrated the slowest rate of recovery amongst the achromat group. Conclusions: In this, the largest study of DA functions in molecularly proven ACHM to date, we have identified optimal testing conditions that accentuate the relative difference between achromats and normal observers. These findings can help optimize DA testing in future trials, as well as help resolve the dichotomy in the literature regarding the normality or otherwise of DA functions in ACHM. Furthermore, the shorter testing time and less intense adaptation light used in these experiments may prove advantageous for more readily and reliably probing scotopic function in retinal disease, and be particularly valuable in the frequent post-therapeutic assessments required in the context of the marked photophobia in ACHM.
    Investigative ophthalmology & visual science. 08/2014;
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    ABSTRACT: Purpose: To longitudinally characterize retinal structure and function in achromatopsia (ACHM) in preparation for clinical gene therapy trials. Methods: 38 molecularly confirmed ACHM subjects underwent serial assessments, including spectral domain optical coherence tomography (SD-OCT), microperimetry, and fundus autofluorescence (FAF). Foveal structure on SD-OCT was graded and compared for evidence of progression, along with serial measurements of foveal total retinal thickness (FTRT) and outer nuclear layer (ONL) thickness. FAF patterns were characterized and compared over time. Results: Mean follow-up was 19.5 months (age range at baseline: 6-52 years). Only 2 of 37 subjects (5%) demonstrated change in serial foveal SD-OCT scans. There was no statistically significant change over time in FTRT (p=0.83), ONL thickness (p=0.27), hyporeflective zone (HRZ) diameter (p=0.42), visual acuity (p=0.89), contrast sensitivity (p=0.22), mean retinal sensitivity (p=0.84), and fixation stability (p=0.58). Three distinct FAF patterns were observed (n=30): central increased FAF (n=4), normal FAF (n=11), and well-demarcated reduced FAF (n=15); with the latter group displaying a slow increase in the area of reduced FAF of 0.03 mm2 over 19.3 months (p=0.002). Conclusions: Previously published cross-sectional studies have described conflicting findings with respect to the age-dependency of progression. This study, which constitutes the largest and longest prospective longitudinal study of ACHM to date, suggests that although ACHM may be progressive, any such progression is slow and subtle in most patients, and does not correlate with age or genotype. We also describe the first serial assessment of FAF, which is highly variable between individuals, even of similar age and genotype.
    Investigative ophthalmology & visual science. 08/2014;
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    ABSTRACT: Mutations in the OPN1LW (L-) and OPN1MW (M-) cone opsin genes underlie a spectrum of cone photoreceptor defects from stationary loss of colour vision to progressive retinal degeneration. Genotypes of 22 families with a range of cone disorders were grouped into three classes: deletions of the Locus Control Region (LCR); missense mutation (p.Cys203Arg) in an L-/M- hybrid gene; and exon 3 single nucleotide polymorphism (SNP) interchange haplotypes in an otherwise normal gene array. Moderate to high myopia was observed in all mutation categories. Individuals with LCR deletions or p.Cys203Arg mutations were more likely to have nystagmus and poor vision, with disease progression in some p.Cys203Arg patients. Three disease-associated exon 3 SNP haplotypes encoding LIAVA, LVAVA or MIAVA, were identified in our cohort. These patients were less likely to have nystagmus but more likely to show progression, with all patients over the age of 40 having marked macular abnormalities. Previously, the haplotype LIAVA has been shown to result in exon 3 skipping. Here we show that haplotypes LVAVA and MIAVA also result in aberrant splicing, with a residual low level of correctly spliced cone opsin. The OPN1LW/OPN1MW:c.532A>G SNP, common to all three disease-associated haplotypes, appears to be principally responsible for this mutational mechanism.This article is protected by copyright. All rights reserved
    Human Mutation 08/2014; · 5.21 Impact Factor
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    ABSTRACT: Enhanced S-cone syndrome (ESCS) forms part of the differential diagnosis of night blindness in childhood.
    Jama Ophthalmology 07/2014; · 3.83 Impact Factor
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    ABSTRACT: IMPORTANCE We describe novel ocular phenotypic features caused by mutations in ADAMTS18. The exact role of ADAMTS18 in ocular disease is unclear, and our work further contributes to the understanding of this gene and its protein. OBJECTIVE To expand the phenotypic characterization in patients with homozygous mutations in ADAMTS18 and report novel mutational data. DESIGN, SETTING, AND PARTICIPANTS A case series with genetic investigations was conducted at tertiary referral clinical and university settings. Three families participated. MAIN OUTCOME MEASURES Phenotype and genotype description of 3 families. RESULTS Four affected patients from 3 families with an unusual ocular phenotype had full ophthalmic and systemic examination. A single affected individual in the first family had bilateral microcornea, ectopic pupils, and cone-rod dystrophy. In a second family, 2 brothers showed bilateral microcornea, childhood cataract, ectopia lentis, rhegmatogenous retinal detachment, and cone-rod dystrophy. In the third family, a single affected individual had the same features as those in family 2, without ectopia lentis. Causative mutations were sought using homozygosity mapping, Sanger sequencing, and massively parallel sequencing of the whole exome. Novel homozygous mutations in ADAMTS18 were identified, consisting of c.1067T>A [p.L356*] in the first proband, c.2159G>C [p.C720S] in the 2 affected brothers, and c.1952G>A [p.R651Q] in the third proband. All 3 mutations are predicted to be pathogenic. CONCLUSIONS AND RELEVANCE Mutations in ADAMTS18 are associated with ocular developmental abnormalities including microcornea, ectopia lentis, and early onset of cone-rod dystrophy. This report provides further evidence that ADAMTS18 plays a key role in ocular development. Physicians should consider screening ADAMTS18 in patients with microcornea and cone-rod dystrophy.
    Jama Ophthalmology 05/2014; · 3.83 Impact Factor
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    ABSTRACT: In a subset of inherited retinal degenerations (including cone, cone-rod, and macular dystrophies), cone photoreceptors are more severely affected than rods; ABCA4 mutations are the most common cause of this heterogeneous class of disorders. To identify retinal-disease-associated genes, we performed exome sequencing in 28 individuals with "cone-first" retinal disease and clinical features atypical for ABCA4 retinopathy. We then conducted a gene-based case-control association study with an internal exome data set as the control group. TTLL5, encoding a tubulin glutamylase, was highlighted as the most likely disease-associated gene; 2 of 28 affected subjects harbored presumed loss-of-function variants: c.[1586_1589delAGAG];[1586_1589delAGAG], p.[Glu529Valfs(∗)2];[Glu529Valfs(∗)2], and c.[401delT(;)3354G>A], p.[Leu134Argfs(∗)45(;)Trp1118(∗)]. We then inspected previously collected exome sequence data from individuals with related phenotypes and found two siblings with homozygous nonsense variant c.1627G>T (p.Glu543(∗)) in TTLL5. Subsequently, we tested a panel of 55 probands with retinal dystrophy for TTLL5 mutations; one proband had a homozygous missense change (c.1627G>A [p.Glu543Lys]). The retinal phenotype was highly similar in three of four families; the sibling pair had a more severe, early-onset disease. In human and murine retinae, TTLL5 localized to the centrioles at the base of the connecting cilium. TTLL5 has been previously reported to be essential for the correct function of sperm flagella in mice and play a role in polyglutamylation of primary cilia in vitro. Notably, genes involved in the polyglutamylation and deglutamylation of tubulin have been associated with photoreceptor degeneration in mice. The electrophysiological and fundus autofluorescence imaging presented here should facilitate the molecular diagnosis in further families.
    The American Journal of Human Genetics 05/2014; 94(5):760-9. · 11.20 Impact Factor
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    ABSTRACT: Idiopathic infantile nystagmus (IIN) is a genetically heterogeneous disorder, often associated with FRMD7 mutations. As the appearance of the retina is reported to be normal based on conventional fundus photography, IIN is postulated to arise from abnormal cortical development.To determine whether the afferent visual system is involved in FRMD7 mutations, we performed in-situ hybridisation studies in human embryonic and foetal stages (35 days post ovulation to 9 weeks post conception). We show a dynamic retinal expression pattern of FRMD7 during development. We observe expression within the outer neuroblastic layer, then in the inner neuroblastic layer and at 9 weeks post conception a bi-laminar expression pattern. Expression was also noted within the developing optic stalk and optic disc.We identified a large cohort of IIN patients (n=100), and performed sequence analysis which revealed 45 patients with FRMD7 mutations. Patients with FRMD7 mutations underwent detailed retinal imaging studies using ultra-high resolution optical coherence tomography. The tomograms were compared to a control cohort (n=60). The foveal pit was significantly shallower in FRMD7 patients (p<0.0001). The optic nerve head morphology was abnormal with significantly decreased optic disc area, retinal nerve fibre layer thickness, cup area and cup depth in FRMD7 patients (p<0.0001).This study shows for the first time that abnormal afferent system development is associated with FRMD7 mutations and could be an important aetiological factor in the development of nystagmus.
    Human Molecular Genetics 03/2014; · 7.69 Impact Factor
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    ABSTRACT: To describe the phenotypic and genotypic features in patients with PRPH2 mutations and negative electroretinograms. Retrospective observational case series. Records of patients with a confirmed molecular diagnosis of PRPH2 mutation, and an electronegative electroretinogram (reduced b-wave to a-wave amplitude ratio) under either photopic or scotopic conditions, were identified. Data examined included clinical history and retinal images, electrophysiology, and mutational analysis. Six patients were ascertained. All had presented with clinically evident maculopathy and Snellen visual acuities in the range of 6/6 to 1/60. All had negative electroretinograms in scotopic or photopic electroretinograms or both. Four patients were heterozygous for a previously reported missense mutation c.514C>T, p.R172W; 2 were heterozygous for the frame-shifting mutations c.259_266del8, p.D87fs and c.394delC, p.Q132fs. No other cause of electronegative electroretinogram was identified in any patient. Photopic On- and Off-response recording was useful in identifying On-pathway dysfunction. PRPH2 mutation can be associated with negative electroretinograms. This novel finding is not mutation specific and does not relate to the severity of the disease. The data add to the documented phenotypical variability of PRPH2 mutations and represent a further cause of negative electroretinogram.
    Retina (Philadelphia, Pa.) 03/2014; · 2.93 Impact Factor
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    ABSTRACT: Purpose: In this study, we characterize and model changes in visual performance associated with a Tyr99Cys substitution in the guanylate cyclase activating protein (GCAP1) in four family members aged between 39 and 55 years. Guanylate cyclase and its activating protein are molecules in the visual transduction pathway that restore cyclic GMP (cGMP) following its light-activated hydrolysis. The mutation causes an excess of cGMP in the dark and results in progressive photoreceptor loss. Methods: L-cone temporal acuity was measured as a function of target irradiance; and L-cone temporal contrast-sensitivity was measured as a function of temporal frequency. Results: All four GCAP1-mutant family members show sensitivity or acuity losses relative to normal observers. The data for the youngest family member are consistent with an abnormal speeding up of the visual response relative to normals, but those for the older members show a progressive higher-frequency sensitivity loss consistent with a slowing down of their response. Conclusions: The speeding up of the visual response in the youngest observer is consistent with the Tyr99Cys-mutation resulting in the more rapid replacement of cGMP after light exposure, and thus in a reduction of temporal integration and relative improvement in high frequency sensitivity compared to normals. The high-frequency losses in the older observers are consistent with their vision being further limited by the interposition of some sluggish process. This might result from some residual or malfunctioning molecular process limiting transduction within damaged photoreceptors, or from an active or passive postreceptoral reorganization caused by the paucity of functioning photoreceptors.
    Investigative ophthalmology & visual science 02/2014; · 3.43 Impact Factor
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    ABSTRACT: To provide a detailed phenotype/genotype characterization of Bietti crystalline dystrophy (BCD). Observational case series. Twenty patients from 17 families recruited from a multiethnic British population. Patients underwent color fundus photography, near-infrared (NIR) imaging, fundus autofluorescence (FAF) imaging, spectral domain optical coherence tomography (SD-OCT), and electroretinogram (ERG) assessment. The gene CYP4V2 was sequenced. Clinical, imaging, electrophysiologic, and molecular genetics findings. Patients ranged in age from 19 to 72 years (median, 40 years), with a visual acuity of 6/5 to perception of light (median, 6/12). There was wide intrafamilial and interfamilial variability in clinical severity. The FAF imaging showed well-defined areas of retinal pigment epithelium (RPE) loss that corresponded on SD-OCT to well-demarcated areas of outer retinal atrophy. Retinal crystals were not evident on FAF imaging and were best visualized with NIR imaging. Spectral domain OCT showed them to be principally located on or in the RPE/Bruch's membrane complex. Disappearance of the crystals, revealed by serial recording, was associated with severe disruption and thinning of the RPE/Bruch's membrane complex. Cases with extensive RPE degeneration (N = 5) had ERGs consistent with generalized rod and cone dysfunction, but those with more focal RPE atrophy showed amplitude reduction without delay (N = 3), consistent with restricted loss of function, or that was normal (N = 2). Likely disease-causing variants were identified in 34 chromosomes from 17 families. Seven were novel, including p.Met66Arg, found in all 11 patients from 8 families of South Asian descent. This mutation appears to be associated with earlier onset (median age, 30 years) compared with other substitutions (median age, 41 years). Deletions of exon 7 were associated with more severe disease. The phenotype is highly variable. Several novel variants are reported, including a highly prevalent substitution in patients of South Asian descent that is associated with earlier-onset disease. Autofluorescence showed sharply demarcated areas of RPE loss that coincided with abrupt edges of outer retinal atrophy on SD-OCT; crystals were generally situated on or in the RPE/Bruch's complex but could disappear over time with associated RPE disruption. These results support a role for the RPE in disease pathogenesis.
    Ophthalmology 01/2014; · 5.56 Impact Factor
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    ABSTRACT: To describe the phenotype, associations, and complications of dome-shaped macula (DSM) through the combination of spectral-domain optical coherence tomography (OCT) imaging and B-scan ultrasonography, when available. This retroprospective cohort study aims to gain further pathophysiological understanding in eyes with DSM. Fifty-eight eyes of 36 patients were identified as having OCT features of DSM. Retinal and choroidal thicknesses were determined from enhanced depth imaging (EDI)-OCT image sets, with scleral thickness subsequently calculated by subtraction from the B-scan ultrasound-derived measurements of posterior coat thickness. DSM was associated with myopia in 81 % of eyes. The underlying clinical diagnosis was variable: central serous chorioretinopathy (CSCR)-like entity, choroidal neovascularization, and inherited retinal disorders. The subfoveal choroidal thickness of the nine highly myopic eyes with a CSCR-like phenotype was thicker than the 25 eyes without CSCR (p = 0.169). The mean subfoveal scleral thickness of the highly myopic eyes was 585 ± 196 μm, which was significantly different from those with a refractive error less than 6 diopters (1133 ± 290 μm) (P < 0.0001). This study highlights the novel observation of a thickened choroid when CSCR is present. In addition, we expand the associations of DSM to eyes with hypermetropia and acquired disease, and to those with inherited retinal dystrophies.
    Albrecht von Graæes Archiv für Ophthalmologie 01/2014; · 1.93 Impact Factor
  • Acta ophthalmologica 01/2014; · 2.44 Impact Factor
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    ABSTRACT: Purpose: The effect of increased numbers of S-cone photoreceptors in enhanced S-cone syndrome (ESCS) was investigated psychophysically in six ESCS observers to understand more about the relative cone sensitivities and postreceptoral organization. Methods: Measures of temporal sensitivity or delay were made: S- and L-cone temporal acuity (critical flicker fusion or cff), S-cone temporal contrast sensitivity, and S-cone delay. Results: ESCS observers showed uniform enhancements of S-cone cff of between 0.85 and 6.25 Hz, but reductions in L-cone cff. They also showed higher S-cone temporal-contrast-sensitivities at medium and high S-cone adaptation levels with sensitivity functions that peaked near 7.5 Hz but fell off at lower and higher frequencies; in contrast, the mean normal function was flat at low frequencies and fell-off only at high frequencies. The S-cone signal, as in the normal, is subject to large phase delays. Conclusions: We interpret the enhancements in cff as increases in S-cone number in ESCS of between 1.39 and 11.32 times normal density (with a mean of 3.48). The peaked ESCS contrast-sensitivity functions are consistent with S-cone signal interactions that increase sensitivity at intermediate frequencies through constructive interference but decrease it at lower and higher frequencies through destructive interference. Measures of S-cone delays relative to L- and M-cone signals show that the predominant S-cone signals in ESCS are negative and delayed as in normal observers, but reveal another faster, positive S-cone signal. This signal is also likely to be the cause of constructive and destructive interference in the contrast-sensitivity data of ESCS observers.
    Investigative ophthalmology & visual science 01/2014; · 3.43 Impact Factor
  • Ravjit Singh, Kaoru Fujinami, Anthony T Moore
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    ABSTRACT: To report a case of branch retinal artery occlusion and prepapillary loop in a 10-year-old girl.
    Retinal Cases & Brief Reports 01/2014; 8(2):124-6.
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    ABSTRACT: Purpose: We report a psychophysical investigation of five observers with the retinal disorder "cone dystrophy with supernormal rod ERG", caused by mutations in the gene KCNV2 that encodes a voltage-gated potassium channel found in rod and cone photoreceptors. We compare losses for rod- and for cone-mediated vision to further investigate the disorder and to assess whether the supernormal ERG is associated with any visual benefit. Methods: L-cone, S-cone and rod temporal acuity (critical flicker fusion frequency-cff) was measured as a function of target irradiance; L-cone temporal contrast-sensitivity was measured as a function of temporal frequency. Results: Temporal acuity measures reveal that losses for vision mediated by rods, S-cones and L-cones are roughly equivalent. Further, the gain in rod function implied by the supernormal ERG provides no apparent benefit to near-threshold rod-mediated visual performance. The L-cone temporal contrast-sensitivity function in affected observers is similar in shape to the mean normal function but only after the mean function has been compressed by halving the logarithmic sensitivities. Conclusions: The name of this disorder is potentially misleading because the comparable losses found across rod and cone vision suggest that the disorder is a generalized cone-rod dystrophy. Temporal acuity and temporal contrast-sensitivity measures are broadly consistent with the defect in the voltage-gated potassium channel producing a nonlinear distortion of the photoreceptor response but after otherwise normal transduction processes.
    Investigative ophthalmology & visual science 12/2013; · 3.43 Impact Factor

Publication Stats

3k Citations
898.41 Total Impact Points

Institutions

  • 2014
    • Great Ormond Street Hospital for Children NHS Foundation Trust
      • Clinical and Academic Department of Ophthalmology (CADO)
      Londinium, England, United Kingdom
  • 2009–2014
    • UCL Eastman Dental Institute
      Londinium, England, United Kingdom
  • 2002–2014
    • University College London
      • Institute of Ophthalmology
      Londinium, England, United Kingdom
  • 1997–2014
    • Moorfields Eye Hospital NHS Foundation Trust
      • Department of Medical Retina
      Londinium, England, United Kingdom
  • 2013
    • Keio University
      • Department of Ophthalmology
      Edo, Tōkyō, Japan
    • NIHR Oxford Biomedical Research
      Oxford, England, United Kingdom
    • University of Oxford
      • Nuffield Department of Clinical Neurosciences
      Oxford, ENG, United Kingdom
  • 2011
    • UK Department of Health
      Londinium, England, United Kingdom
  • 2006–2011
    • University of Cambridge
      • Department of Medical Genetics
      Cambridge, ENG, United Kingdom
  • 2010
    • London Research Institute
      Londinium, England, United Kingdom
  • 2005–2010
    • University of Birmingham
      • Institute for Biomedical Research
      Birmingham, ENG, United Kingdom
  • 2002–2009
    • University of Leeds
      • Leeds Institute of Molecular Medicine (LIMM)
      Leeds, ENG, United Kingdom