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Simunovic MP, Shen W, Lin JY, Protti DA, Lisowski L, Gillies MC. Optogenetic approaches to vision restoration. Exp Eye Res 2018; 178:15-26. [PMID: 30218651 DOI: 10.1016/j.exer.2018.09.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 08/16/2018] [Accepted: 09/07/2018] [Indexed: 10/28/2022]
Abstract
Inherited retinal disease (IRD) affects about 1 in 3000 to 1 in 5000 individuals and is now believed to be the most common cause of blindness registration in developed countries. Until recently, the management of such conditions had been exclusively supportive. However, advances in molecular biology and medical engineering have now seen the rise of a variety of approaches to restore vision in patients with IRDs. Optogenetic approaches are primarily aimed at rendering secondary and tertiary neurons of the retina light-sensitive in order to replace degenerate or dysfunctional photoreceptors. Such approaches are attractive because they provide a "causative gene-independent" strategy, which may prove suitable for a variety of patients with IRD. We discuss theoretical and practical considerations in the selection of optogenetic molecules, vectors, surgical approaches and review previous trials of optogenetics for vision restoration. Optogenetic approaches to vision restoration have yielded promising results in pre-clinical trials and a phase I/II clinical trial is currently underway (ClinicalTrials.gov NCT02556736). Despite the significant inroads made in recent years, the ideal optogenetic molecule, vector and surgical approach have yet to be established.
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Affiliation(s)
- M P Simunovic
- Save Sight Institute, University of Sydney, 8 Macquarie St., Sydney, NSW, 2000, Australia; Retinal Unit, Sydney Eye Hospital, 8 Macquarie St., Sydney, NSW, 2000, Australia.
| | - W Shen
- Retinal Unit, Sydney Eye Hospital, 8 Macquarie St., Sydney, NSW, 2000, Australia
| | - J Y Lin
- Faculty of Health, University of Tasmania, Private Bag 23, Hobart, TAS, 7000, Australia
| | - D A Protti
- Discipline of Physiology, University of Sydney, NSW, 2006, Australia
| | - L Lisowski
- Children's Medical Research Institute, University of Sydney, NSW, 2006, Australia; Military Institute of Hygiene and Epidemiology, 24-100, Puławy, Poland
| | - M C Gillies
- Save Sight Institute, University of Sydney, 8 Macquarie St., Sydney, NSW, 2000, Australia; Retinal Unit, Sydney Eye Hospital, 8 Macquarie St., Sydney, NSW, 2000, Australia
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Edwards TL, Xue K, Meenink HCM, Beelen MJ, Naus GJL, Simunovic MP, Latasiewicz M, Farmery AD, de Smet MD, MacLaren RE. First-in-human study of the safety and viability of intraocular robotic surgery. Nat Biomed Eng 2018; 2:649-656. [PMID: 30263872 DOI: 10.1038/s41551-018-0248-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Microsurgery of the retina would be dramatically improved by instruments that offer supra-human precision. Here, we report the results of a first-in-human study of remotely controlled robot-assisted retinal surgery performed through a telemanipulation device. Specifically, 12 patients requiring dissection of the epiretinal or inner limiting membrane over the macula were randomly assigned to either undergo robot-assisted-surgery or manual surgery, under general anaesthesia. We evaluated surgical success, duration of surgery and amount of retinal microtrauma as a proxy for safety. Surgical outcomes were equally successful in the robotic-surgery and manual-surgery groups. Differences in the amount of retinal microtrauma between the two groups were statistically insignificant, yet dissection took longer with robotic surgery (median time, 4 min 5 s) than with manual surgery (1 min 20 s). We also show the feasibility of using the robot to inject recombinant tissue plasminogen activator under the retina to displace sight-threatening haemorrhage in three patients under local anaesthesia. A safe and viable robotic system for intraocular surgery would enable precise and minimally traumatic delivery of gene therapy or cell therapy to the retina.
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Affiliation(s)
- T L Edwards
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - K Xue
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | | | | | | | - M P Simunovic
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - M Latasiewicz
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - A D Farmery
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | | | - R E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK. .,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
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Edwards TL, Williams J, Patrício MI, Simunovic MP, Shanks M, Clouston P, MacLaren RE. Novel non-contiguous exon duplication in choroideremia. Clin Genet 2017; 93:144-148. [PMID: 28369842 DOI: 10.1111/cge.13021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/03/2017] [Accepted: 03/23/2017] [Indexed: 12/16/2022]
Abstract
The importance of establishing a genetic diagnosis in patients with a choroideremia phenotype has been underscored by the advent of gene replacement therapy for this condition. Here, we describe a complex imbalance at the CHM locus in a male patient with classical disease. At the DNA level, this imbalance consists of 2 non-contiguous duplications (exons 1-2 and 9-12). Further characterization suggests the generation of 2 independent CHM transcriptional units, one of which may produce a deleted form of the Rab escort protein 1 protein. Expression of such a type of aberrant protein in photoreceptors may have important implications when considering gene therapy for this disorder.
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Affiliation(s)
- T L Edwards
- Department of Clinical Neurosciences, Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospital NHS Foundation Trust, Oxford, UK
| | - J Williams
- Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford University Hospital NHS Foundation Trust, Oxford, UK
| | - M I Patrício
- Department of Clinical Neurosciences, Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - M P Simunovic
- Department of Clinical Neurosciences, Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospital NHS Foundation Trust, Oxford, UK
| | - M Shanks
- Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford University Hospital NHS Foundation Trust, Oxford, UK
| | - P Clouston
- Oxford Medical Genetics Laboratories, Churchill Hospital, Oxford University Hospital NHS Foundation Trust, Oxford, UK
| | - R E MacLaren
- Department of Clinical Neurosciences, Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.,Oxford Eye Hospital, Oxford University Hospital NHS Foundation Trust, Oxford, UK.,Moorfields Eye Hospital, UCL Institute of Ophthalmology NIHR Biomedical Research Centre, London, UK
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Abstract
Colour vision deficiency is one of the commonest disorders of vision and can be divided into congenital and acquired forms. Congenital colour vision deficiency affects as many as 8% of males and 0.5% of females--the difference in prevalence reflects the fact that the commonest forms of congenital colour vision deficiency are inherited in an X-linked recessive manner. Until relatively recently, our understanding of the pathophysiological basis of colour vision deficiency largely rested on behavioural data; however, modern molecular genetic techniques have helped to elucidate its mechanisms. The current management of congenital colour vision deficiency lies chiefly in appropriate counselling (including career counselling). Although visual aids may be of benefit to those with colour vision deficiency when performing certain tasks, the evidence suggests that they do not enable wearers to obtain normal colour discrimination. In the future, gene therapy remains a possibility, with animal models demonstrating amelioration following treatment.
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Michaelides M, Johnson S, Simunovic MP, Bradshaw K, Holder G, Mollon JD, Moore AT, Hunt DM. Blue cone monochromatism: a phenotype and genotype assessment with evidence of progressive loss of cone function in older individuals. Eye (Lond) 2005; 19:2-10. [PMID: 15094734 DOI: 10.1038/sj.eye.6701391] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
AIM To perform a detailed clinical and psychophysical assessment of the members of three British families affected with blue cone monochromatism (BCM), and to determine the molecular basis of disease in these families. METHODS Affected and unaffected members of three families with BCM were examined clinically and underwent electrophysiological and detailed psychophysical testing. Blood samples were taken for DNA extraction. The strategy for molecular analysis was to amplify the coding regions of the long wavelength-sensitive (L) and middle wavelength-sensitive (M) cone opsin genes and the upstream locus control region by polymerase chain reaction, and to examine these fragments for mutations by direct sequencing. RESULTS We have confirmed the reported finding of protan-like D-15 arrangements of patients with BCM. In addition, we have demonstrated that the Mollon-Reffin (MR) Minimal test is a useful colour-discrimination test to aid in the diagnosis of BCM. Affected males were shown to fail the protan and deutan axes, but retained good discrimination on the tritan axis of the MR test, a compelling evidence for residual colour vision in BCM. This residual tritan discrimination was also readily detected with HRR plates. In two families, psychophysical testing demonstrated evidence for progression of disease. In two pedigrees, BCM could be linked to unequal crossovers within the opsin gene array that resulted in a single 5'-L/M-3' hybrid gene, with an inactivating Cys203Arg mutation. The causative mutations were not identified in the third family. CONCLUSIONS The MR test is a useful method of detecting BCM across a wide range of age groups; residual tritan colour discrimination is clearly demonstrated and allows BCM to be distinguished from rod monochromatism. BCM is usually classified as a stationary cone dysfunction syndrome; however, two of our families show evidence of progression. This is the first report of progression associated with a genotype consisting of a single 5'-L/M-3' hybrid gene carrying an inactivating mutation. We have confirmed that the Cys203Arg inactivating mutation is a common sequence change in blue cone monochromats.
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Affiliation(s)
- M Michaelides
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
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Simunovic MP, Regan BC, Mollon JD. Is color vision deficiency an advantage under scotopic conditions? Invest Ophthalmol Vis Sci 2001; 42:3357-64. [PMID: 11726645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
PURPOSE To examine experimentally whether color vision deficiency confers a selective advantage under scotopic conditions. METHODS Red-green color-deficient subjects, monochromats, and age-matched color-normal control subjects were examined. In each subject the time course of dark adaptation, scotopic visual field sensitivity, and performance on a scotopic perceptual task were measured. RESULTS No significant differences were found between red-green color-deficient subjects and control subjects on any of the three tests. Our small sample of monochromats had higher absolute thresholds than the corresponding control subjects, but their performance at the scotopic visual field test and perceptual task did not differ significantly from that of color-normal subjects. CONCLUSIONS No evidence was found that red-green color deficiency or monochromatism confers a selective advantage under scotopic conditions.
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Affiliation(s)
- M P Simunovic
- Department of Experimental Psychology, Cambridge University, Cambridge, United Kingdom.
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Abstract
Many colour tests require a visual acuity of at least 0.1, making them unsuitable for low vision patients. To assess colour vision in patients with sub-normal acuity, we re-designed a previously described test so that its spatial details would be coarse enough to be resolvable by subjects with severe visual impairment. The test measures chromatic discrimination along 20 axes evenly spaced in CIE 1976 L*u*v* colour space. We detail the results for this test in a group of patients with dominant optic atrophy. Despite the lack of evidence for genetic heterogeneity in dominant optic atrophy, we observed phenotypic variation both between and within families.
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Affiliation(s)
- M P Simunovic
- Department of Experimental Psychology, Cambridge University, UK
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Abstract
The cone dystrophies are a heterogeneous group of inherited disorders that result in dysfunction of the cone photoreceptors and sometimes their post-receptoral pathways. The major clinical features of cone dystrophy are photophobia, reduced visual acuity and abnormal colour vision. Ganzfeld electroretinography shows reduced or absent cone responses. On the basis of their natural history, the cone dystrophies may be broadly divided into two groups: stationary and progressive cone dystrophies. The stationary cone dystrophies have received more attention, and subsequently our knowledge of their molecular genetic, psychophysical and clinical characteristics is better developed. Various methods of classification have been proposed for the progressive cone dystrophies, but none is entirely satisfactory, largely because the underlying disease mechanisms are poorly understood. Multidisciplinary studies involving clinical assessment, molecular genetics, electrophysiology and psychophysics should lead to an improved understanding of the pathogenesis of these disorders.
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Affiliation(s)
- M P Simunovic
- Department of Experimental Psychology, University of Cambridge, UK
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Abstract
The procedure of radial keratotomy produces an abnormal corneal topography, with the central cornea being flatter than the periphery. As a result, fitting the post-radial keratotomy (RK) patient with rigid gas permeable (RGP) lenses can be an enormously difficult task. Unlike standard lens designs, the Ortho-K series of lenses, originally designed for use in orthokeratology, possess a back peripheral radius (BPR) which is steeper than the back optic zone radius (BOZR). It is proposed that these lenses may provide a more acceptable fit than conventional RGPs for the post-RK patient.
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