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Schaeffel F, Swiatczak B. Mechanisms of emmetropization and what might go wrong in myopia. Vision Res 2024; 220:108402. [PMID: 38705024 DOI: 10.1016/j.visres.2024.108402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/25/2024] [Accepted: 03/25/2024] [Indexed: 05/07/2024]
Abstract
Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses retinal image defocus as an error signal, a mechanism called emmetropization. The sensor to detect defocus and its sign resides in the retina itself. The retina and/or the retinal pigment epithelium (RPE) presumably releases biochemical messengers to change choroidal thickness and modulate the growth rates of the underlying sclera. A central question arises: if emmetropization operates as a closed-loop system, why does it not stop myopia development? Recent experiments in young human subjects have shown that (1) the emmetropic retina can perfectly distinguish between real positive defocus and simulated defocus, and trigger transient axial eye shortening or elongation, respectively. (2) Strikingly, the myopic retina has reduced ability to inhibit eye growth when positive defocus is imposed. (3) The bi-directional response of the emmetropic retina is elicited with low spatial frequency information below 8 cyc/deg, which makes it unlikely that optical higher-order aberrations play a role. (4) The retinal mechanism for the detection of the sign of defocus involves a comparison of defocus blur in the blue (S-cone) and red end of the spectrum (L + M-cones) but, again, the myopic retina is not responsive, at least not in short-term experiments. This suggests that it cannot fully trigger the inhibitory arm of the emmetropization feedback loop. As a result, with an open feedback loop, myopia development becomes "open-loop".
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Affiliation(s)
- Frank Schaeffel
- Myopia Research Group, Institute of Molecular and Clinical Ophthalmology Basel (IOB), Switzerland; Section Neurobiology of the Eye, Institute of Ophthalmic Research, University of Tübingen, Germany; Zeiss Vision Lab, Institute of Ophthalmic Research, University of Tübingen, Germany.
| | - Barbara Swiatczak
- Myopia Research Group, Institute of Molecular and Clinical Ophthalmology Basel (IOB), Switzerland
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2
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Wang K, Han G, Hao R. Advances in the study of the influence of photoreceptors on the development of myopia. Exp Eye Res 2024; 245:109976. [PMID: 38897270 DOI: 10.1016/j.exer.2024.109976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 06/12/2024] [Accepted: 06/16/2024] [Indexed: 06/21/2024]
Abstract
This review examines the pivotal role of photoreceptor cells in ocular refraction development, focusing on dopamine (DA) as a key neurotransmitter. Contrary to the earlier view favoring cone cells, recent studies have highlighted the substantial contributions of both rod and cone cells to the visual signaling pathways that influence ocular refractive development. Notably, rod cells appeared to play a central role. Photoreceptor cells interact intricately with circadian rhythms, color vision pathways, and other neurotransmitters, all of which are crucial for the complex mechanisms driving the development of myopia. This review emphasizes that ocular refractive development results from a coordinated interplay between diverse cell types, signaling pathways, and neurotransmitters. This perspective has significant implications for unraveling the complex mechanisms underlying myopia and aiding in the development of more effective prevention and treatment strategies.
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Affiliation(s)
- Kailei Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, 300020, PR China; Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Hospital, Tianjin, 300020, PR China
| | - Guoge Han
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, 300020, PR China; Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Hospital, Tianjin, 300020, PR China; Nankai University Eye Institute, Nankai University Affiliated Eye Hospital, Nankai University, Tianjin, 300020, PR China.
| | - Rui Hao
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, 300020, PR China; Tianjin Key Lab of Ophthalmology and Vision Science, Tianjin Eye Hospital, Tianjin, 300020, PR China; Nankai University Eye Institute, Nankai University Affiliated Eye Hospital, Nankai University, Tianjin, 300020, PR China.
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3
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Huang Y, Chen X, Zhuang J, Yu K. The Role of Retinal Dysfunction in Myopia Development. Cell Mol Neurobiol 2022:10.1007/s10571-022-01309-1. [DOI: 10.1007/s10571-022-01309-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 11/16/2022] [Indexed: 11/27/2022]
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4
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Efficacy of 0.01% atropine for myopia control in a randomized, placebo-controlled trial depends on baseline electroretinal response. Sci Rep 2022; 12:11588. [PMID: 35804049 PMCID: PMC9270320 DOI: 10.1038/s41598-022-15686-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 06/28/2022] [Indexed: 11/30/2022] Open
Abstract
This study aimed to evaluate the efficacy of 18-month 0.01% atropine in 61 myopic children (aged 7–10) and the relationship with central retinal response (by multifocal electroretinogram [mfERG]) in a double-masked randomized placebo-controlled clinical trial. Global-flash mfERG was measured at baseline, while cycloplegic spherical equivalent refraction (SER) and axial length (AL) were measured at baseline and at 6-month intervals. Annualized change in SER and AL were compared between atropine and control groups, and the relationships with baseline mfERG were evaluated. Changes in SER (−0.70 ± 0.39D vs. −0.66 ± 0.41D, p = 0.63) and AL (0.32 ± 0.16 mm vs. 0.30 ± 0.22 mm, p = 0.52) were similar in atropine and control groups. Interestingly, in the placebo group, mfERG amplitude was negatively correlated with axial elongation (Rp = −0.44, p = 0.03) as in our previous study. However, in the atropine group, an opposite trend was observed that axial elongation was positively correlated with mfERG amplitude (Ra = 0.37, p = 0.04). Annualized myopia progression demonstrated similar opposite effect between atropine and placebo groups but did not reach statistical significance. An ERG screening protocol may be warranted to identify suitable candidates to reduce the likelihood of an unfavorable treatment response by 0.01% atropine.
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Williams KM, Georgiou M, Kalitzeos A, Chow I, Hysi PG, Robson AG, Lingham G, Chen FK, Mackey DA, Webster AR, Hammond CJ, Prokhoda P, Carroll J, Michaelides M, Mahroo OA. Axial Length Distributions in Patients With Genetically Confirmed Inherited Retinal Diseases. Invest Ophthalmol Vis Sci 2022; 63:15. [PMID: 35704304 PMCID: PMC9206393 DOI: 10.1167/iovs.63.6.15] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We investigated axial length (AL) distributions in inherited retinal diseases (IRDs), comparing them with reference cohorts. Methods AL measurements from IRD natural history study participants were included and compared with reference cohorts (TwinsUK, Raine Study Gen2-20, and published studies). Comparing with the Raine Study cohort, formal odds ratios (ORs) for AL ≥ 26 mm or AL ≤ 22 mm were derived for each IRD (Firth's logistic regression model, adjusted for age and sex). Results Measurements were available for 435 patients (median age, 19.5 years). Of 19 diseases, 10 had >10 participants: ABCA4 retinopathy; CNGB3- and CNGA3-associated achromatopsia; RPGR-associated disease; RPE65-associated disease; blue cone monochromacy (BCM); Bornholm eye disease (BED); TYR- and OCA2-associated oculocutaneous albinism; and GPR143-associated ocular albinism. Compared with the TwinsUK cohort (n = 322; median age, 65.1 years) and Raine Study cohort (n = 1335; median age, 19.9 years), AL distributions were wider in the IRD groups. Increased odds for longer ALs were observed for BCM, BED, RPGR, RPE65, OCA2, and TYR; increased odds for short AL were observed for RPE65, TYR, and GPR143. In subanalysis of RPGR-associated disease, longer average ALs occurred in cone-rod dystrophy (n = 5) than rod-cone dystrophy (P = 0.002). Conclusions Several diseases showed increased odds for longer AL (highest OR with BCM); some showed increased odds for shorter AL (highest OR with GPR143). Patients with RPE65- and TYR-associated disease showed increased odds for longer and for shorter eyes. Albinism genes were associated with different effects on AL. These findings add to the phenotype of IRDs and may yield insights into mechanisms of refractive error development.
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Affiliation(s)
- Katie M Williams
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom.,Section of Academic Ophthalmology, School of Life Course Sciences, FoLSM, King's College London, United Kingdom.,Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, FoLSM, King's College London, London, United Kingdom
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom.,Jones Eye Institute, Department of Ophthalmology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Isabelle Chow
- Section of Academic Ophthalmology, School of Life Course Sciences, FoLSM, King's College London, United Kingdom.,Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, FoLSM, King's College London, London, United Kingdom
| | - Pirro G Hysi
- Section of Academic Ophthalmology, School of Life Course Sciences, FoLSM, King's College London, United Kingdom.,Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, FoLSM, King's College London, London, United Kingdom
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Gareth Lingham
- Centre for Ophthalmology and Visual Sciences (Incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Sciences (Incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - David A Mackey
- Centre for Ophthalmology and Visual Sciences (Incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Christopher J Hammond
- Section of Academic Ophthalmology, School of Life Course Sciences, FoLSM, King's College London, United Kingdom.,Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, FoLSM, King's College London, London, United Kingdom
| | - Polina Prokhoda
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom.,Section of Academic Ophthalmology, School of Life Course Sciences, FoLSM, King's College London, United Kingdom.,Department of Twin Research and Genetic Epidemiology, School of Life Course Sciences, FoLSM, King's College London, London, United Kingdom
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6
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Impact of cone abundancy ratios and light spectra on emmetropization in chickens. Exp Eye Res 2022; 219:109086. [DOI: 10.1016/j.exer.2022.109086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 11/21/2022]
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7
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Vohnsen B. Geometrical scaling of the developing eye and photoreceptors and a possible relation to emmetropization and myopia. Vision Res 2021; 189:46-53. [PMID: 34619411 DOI: 10.1016/j.visres.2021.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/10/2021] [Accepted: 09/22/2021] [Indexed: 10/20/2022]
Abstract
In this study the role of vergence in relation to age-dependent scaling of eye and photoreceptor parameters is studied. The underlying hypothesis is that the size and packing of outer segments is matched to the pupil size outdoors in photopic conditions. Vergence is analysed in relation to the angular spectrum of waves being incident using age-dependent data from the literature for the actual geometry and density of photoreceptor cones and rods. This approach is used to derive simple relations for the angular confinement of light along outer segments. Only with a small photopic pupil can leakage and crosstalk for both central and peripheral photoreceptors be entirely ruled out due to the finite length of the outer segments. A limiting 3 mm pupil size is found for children in the school age. Larger pupils will increase the likelihood of leakage and crosstalk that may therefore impact on emmetropization. This study has introduced a new paradigm in myopia research by considering vergence across the 3-D retina as being matched to the angular spectrum of waves being incident from the eye pupil. Emmetropization suggests a delicate balance between photoreceptor outer segment length and density in relation to pupil size. Only when balanced will leakage and crosstalk between adjacent outer segments be effectively suppressed thereby ensuring the highest possible light capture efficiency by visual pigments in the outer segments whether an image is formed on the retina or not.
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Affiliation(s)
- Brian Vohnsen
- Advanced Optical Imaging Group, School of Physics, University College Dublin, Ireland.
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8
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Andersen MKG, Kessel L. Ametropia and Emmetropization in CNGB3 Achromatopsia. Invest Ophthalmol Vis Sci 2021; 62:10. [PMID: 33560291 PMCID: PMC7873492 DOI: 10.1167/iovs.62.2.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 01/18/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose Emmetropization is the process of adjusting ocular growth to the focal plane in order to achieve a clear image. Chromatic light may be involved as a cue to guide this process. Achromats are color blind and lack normal cone function; they are often described as being hyperopic, indicating a failure to emmetropize. We aim to describe the refraction and refractive development in a population of genetically characterized achromats. Methods Refractive error data were collected retrospectively from 28 medical records of CNGB3 c.1148delC homozygous achromats. The distribution of spherical equivalent refractive error (SER) and spherical error was analyzed in adults. The refractive development in children was analyzed by documenting astigmatic refractive error and calculating median SER in 1-year age groups and by analyzing the individual development when possible. Results The distribution of SER and spherical error resembled a Gaussian distribution, indicating that emmetropization was disturbed in achromats, but we found indication of some decrease in SER during the first years of childhood. The prevalence of refractive errors was high and broadly distributed. Astigmatic refractive errors were frequent but did not seem to increase with age. Conclusions Refractive development in achromats is more complicated than a complete failure to emmetropize. The spread of refractive errors is larger than previously documented. Results presented here support the theory that chromatic cues and cone photoreceptors may play a role in emmetropization in humans but that it is not essential.
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Affiliation(s)
| | - Line Kessel
- Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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9
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Hao Q, Zheng M, Weng K, Hao Y, Zhou Y, Lin Y, Gao F, Kou Z, Kawamura S, Yao K, Xu P, Chen J, Zou J. Crumbs proteins stabilize the cone mosaics of photoreceptors and improve vision in zebrafish. J Genet Genomics 2021; 48:52-62. [PMID: 33771456 DOI: 10.1016/j.jgg.2020.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/20/2020] [Accepted: 12/24/2020] [Indexed: 11/28/2022]
Abstract
Although the unique organization of vertebrate cone mosaics was first described long ago, both their underlying molecular basis and physiological significance are largely unknown. Here, we demonstrate that Crumbs proteins, the key regulators of epithelial apical polarity, establish the planar cellular polarity of photoreceptors in zebrafish. Via heterophilic Crb2a-Crb2b interactions, the apicobasal polarity protein Crb2b restricts the asymmetric planar distribution of Crb2a in photoreceptors. The planar polarized Crumbs proteins thus balance intercellular adhesions and tension between photoreceptors, thereby stabilizing the geometric organization of cone mosaics. Notably, loss of Crb2b in zebrafish induces a nearsightedness-like phenotype in zebrafish accompanied by an elongated eye axis and impairs zebrafish visual perception for predation. These data reveal a detailed mechanism for cone mosaic homeostasis via previously undiscovered apical-planar polarity coordination and propose a pathogenic mechanism for nearsightedness.
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Affiliation(s)
- Qinlong Hao
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Mingjie Zheng
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Kechao Weng
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Yumei Hao
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Yao Zhou
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Yuchen Lin
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Feng Gao
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; Department of Cardiology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Ziqi Kou
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Shoji Kawamura
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310058, China
| | - Pinglong Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Jinghai Chen
- The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China; Department of Cardiology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Jian Zou
- Eye Center of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China; The Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou 310058, China.
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10
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Landis EG, Park HN, Chrenek M, He L, Sidhu C, Chakraborty R, Strickland R, Iuvone PM, Pardue MT. Ambient Light Regulates Retinal Dopamine Signaling and Myopia Susceptibility. Invest Ophthalmol Vis Sci 2021; 62:28. [PMID: 33502461 PMCID: PMC7846952 DOI: 10.1167/iovs.62.1.28] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose Exposure to high-intensity or outdoor lighting has been shown to decrease the severity of myopia in both human epidemiological studies and animal models. Currently, it is not fully understood how light interacts with visual signaling to impact myopia. Previous work performed in the mouse retina has demonstrated that functional rod photoreceptors are needed to develop experimentally-induced myopia, alluding to an essential role for rod signaling in refractive development. Methods To determine whether dim rod-dominated illuminance levels influence myopia susceptibility, we housed male C57BL/6J mice under 12:12 light/dark cycles with scotopic (1.6 × 10−3 candela/m2), mesopic (1.6 × 101 cd/m2), or photopic (4.7 × 103 cd/m2) lighting from post-natal day 23 (P23) to P38. Half the mice received monocular exposure to −10 diopter (D) lens defocus from P28–38. Molecular assays to measure expression and content of DA-related genes and protein were conducted to determine how illuminance and lens defocus alter dopamine (DA) synthesis, storage, uptake, and degradation and affect myopia susceptibility in mice. Results We found that mice exposed to either scotopic or photopic lighting developed significantly less severe myopic refractive shifts (lens treated eye minus contralateral eye; –1.62 ± 0.37D and −1.74 ± 0.44D, respectively) than mice exposed to mesopic lighting (–3.61 ± 0.50D; P < 0.005). The 3,4-dihydroxyphenylacetic acid /DA ratio, indicating DA activity, was highest under photopic light regardless of lens defocus treatment (controls: 0.09 ± 0.011 pg/mg, lens defocus: 0.08 ± 0.008 pg/mg). Conclusions Lens defocus interacted with ambient conditions to differentially alter myopia susceptibility and DA-related genes and proteins. Collectively, these results show that scotopic and photopic lighting protect against lens-induced myopia, potentially indicating that a broad range of light levels are important in refractive development.
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Affiliation(s)
- Erica G Landis
- Department of Neuroscience, Emory University, Atlanta, Georgia, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Atlanta, Georgia, United States
| | - Han Na Park
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Micah Chrenek
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Li He
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Curran Sidhu
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States
| | - Ranjay Chakraborty
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Atlanta, Georgia, United States
| | - Ryan Strickland
- Department of Neuroscience, Emory University, Atlanta, Georgia, United States
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University, Atlanta, Georgia, United States.,Department of Pharmacology, Emory University, Atlanta, Georgia, United States
| | - Machelle T Pardue
- Department of Neuroscience, Emory University, Atlanta, Georgia, United States.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Atlanta, Georgia, United States.,Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
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11
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Seifert M, Baden T, Osorio D. The retinal basis of vision in chicken. Semin Cell Dev Biol 2020; 106:106-115. [PMID: 32295724 DOI: 10.1016/j.semcdb.2020.03.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/31/2020] [Accepted: 03/31/2020] [Indexed: 12/20/2022]
Abstract
The Avian retina is far less known than that of mammals such as mouse and macaque, and detailed study is overdue. The chicken (Gallus gallus) has potential as a model, in part because research can build on developmental studies of the eye and nervous system. One can expect differences between bird and mammal retinas simply because whereas most mammals have three types of visual photoreceptor birds normally have six. Spectral pathways and colour vision are of particular interest, because filtering by oil droplets narrows cone spectral sensitivities and birds are probably tetrachromatic. The number of receptor inputs is reflected in the retinal circuitry. The chicken probably has four types of horizontal cell, there are at least 11 types of bipolar cell, often with bi- or tri-stratified axon terminals, and there is a high density of ganglion cells, which make complex connections in the inner plexiform layer. In addition, there is likely to be retinal specialisation, for example chicken photoreceptors and ganglion cells have separate peaks of cell density in the central and dorsal retina, which probably serve different types of behaviour.
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Affiliation(s)
- M Seifert
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK.
| | - T Baden
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK; Institute for Ophthalmic Research, University of Tuebingen, Germany
| | - D Osorio
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK
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12
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Gisbert S, Feldkaemper M, Wahl S, Schaeffel F. Interactions of cone abundancies, opsin expression, and environmental lighting with emmetropization in chickens. Exp Eye Res 2020; 200:108205. [PMID: 32866531 DOI: 10.1016/j.exer.2020.108205] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/21/2020] [Accepted: 08/25/2020] [Indexed: 12/20/2022]
Abstract
We had previously found that M to L cone abundancy ratios in the chicken retina are correlated with vitreous chamber depth and refractive state in chickens eyes, when they have normal visual exposure but not when they develop deprivation myopia. The finding suggests an interaction between cone abundancies and emmetropization. In the current study, we analyzed how stable this correlation was against changes in environmental variables and strain differences. We found that the correlation was preserved in two chicken strains, as long as they were raised in the laboratory facilities and not in the animal facilities of the institute. To determine the reasons for this difference, spectral and temporal lighting parameters were better adjusted in both places, whereas temperature, humidity, food, diurnal lighting cycles and illuminance were already matched. It was also verified that both strains of chickens had the same cone opsin amino acid sequences. The correlation between M to L cone abundancy and ocular biometry is highly susceptible to changes in environmental variables. Yet undetermined differences in lighting parameters were the most likely reasons. Other striking findings were that green cone opsin mRNA expression was downregulated when deprivation myopia developed. Similarly, red opsin mRNA was downregulated when chicks wore red spectacles, which made them more hyperopic. In summary, our experiments show that photoreceptor abundancies, opsin expression, and the responses to deprivation, and therefore emmetropization, are surprisingly dependent on subtle differences in lighting parameters.
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Affiliation(s)
- Sandra Gisbert
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, Elfriede Aulhorn Strasse 7, 72076, Tübingen, Germany
| | - Marita Feldkaemper
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, Elfriede Aulhorn Strasse 7, 72076, Tübingen, Germany
| | - Siegfried Wahl
- ZEISS Vision Science Lab, Ophthalmic Research Institute, Elfriede Aulhorn Strasse 7, 72076, Tübingen, Germany
| | - Frank Schaeffel
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, Elfriede Aulhorn Strasse 7, 72076, Tübingen, Germany; ZEISS Vision Science Lab, Ophthalmic Research Institute, Elfriede Aulhorn Strasse 7, 72076, Tübingen, Germany; Institute of Molecular and Clinical Ophthalmology Basel, Mittlere Strasse 91, CH-4031 Basel, Switzerland.
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13
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Chakraborty R, Ostrin LA, Benavente-Perez A, Verkicharla PK. Optical mechanisms regulating emmetropisation and refractive errors: evidence from animal models. Clin Exp Optom 2019; 103:55-67. [PMID: 31742789 DOI: 10.1111/cxo.12991] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 12/22/2022] Open
Abstract
Our current understanding of emmetropisation and myopia development has evolved from decades of work in various animal models, including chicks, non-human primates, tree shrews, guinea pigs, and mice. Extensive research on optical, biochemical, and environmental mechanisms contributing to refractive error development in animal models has provided insights into eye growth in humans. Importantly, animal models have taught us that eye growth is locally controlled within the eye, and can be influenced by the visual environment. This review will focus on information gained from animal studies regarding the role of optical mechanisms in guiding eye growth, and how these investigations have inspired studies in humans. We will first discuss how researchers came to understand that emmetropisation is guided by visual feedback, and how this can be manipulated by form-deprivation and lens-induced defocus to induce refractive errors in animal models. We will then discuss various aspects of accommodation that have been implicated in refractive error development, including accommodative microfluctuations and accommodative lag. Next, the impact of higher order aberrations and peripheral defocus will be discussed. Lastly, recent evidence suggesting that the spectral and temporal properties of light influence eye growth, and how this might be leveraged to treat myopia in children, will be presented. Taken together, these findings from animal models have significantly advanced our knowledge about the optical mechanisms contributing to eye growth in humans, and will continue to contribute to the development of novel and effective treatment options for slowing myopia progression in children.
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Affiliation(s)
- Ranjay Chakraborty
- College of Nursing and Health Sciences, Optometry and Vision Science, Flinders University, Adelaide, Australia
| | - Lisa A Ostrin
- University of Houston College of Optometry, Houston, Texas, USA
| | | | - Pavan Kumar Verkicharla
- Myopia Research Lab, Prof. Brien Holden Eye Research Centre, LV Prasad Eye Institute, Hyderabad, India
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14
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Lingham G, Mackey DA, Lucas R, Yazar S. How does spending time outdoors protect against myopia? A review. Br J Ophthalmol 2019; 104:593-599. [PMID: 31722876 DOI: 10.1136/bjophthalmol-2019-314675] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 10/07/2019] [Accepted: 10/30/2019] [Indexed: 01/12/2023]
Abstract
Myopia is an increasingly common condition that is associated with significant costs to individuals and society. Moreover, myopia is associated with increased risk of glaucoma, retinal detachment and myopic maculopathy, which in turn can lead to blindness. It is now well established that spending more time outdoors during childhood lowers the risk of developing myopia and may delay progression of myopia. There has been great interest in further exploring this relationship and exploiting it as a public health intervention aimed at preventing myopia in children. However, spending more time outdoors can have detrimental effects, such as increased risk of melanoma, cataract and pterygium. Understanding how spending more time outdoors prevents myopia could advance development of more targeted interventions for myopia. We reviewed the evidence for and against eight facets of spending time outdoors that may protect against myopia: brighter light, reduced peripheral defocus, higher vitamin D levels, differing chromatic spectrum of light, higher physical activity, entrained circadian rhythms, less near work and greater high spatial frequency (SF) energies. There is solid evidence that exposure to brighter light can reduce risk of myopia. Peripheral defocus is able to regulate eye growth but whether spending time outdoors substantially changes peripheral defocus patterns and how this could affect myopia risk is unclear. Spectrum of light, circadian rhythms and SF characteristics are plausible factors, but there is a lack of solid evidence from human studies. Vitamin D, physical activity and near work appear unlikely to mediate the relationship between time spent outdoors and myopia.
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Affiliation(s)
- Gareth Lingham
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, Western Australia, Australia
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, Western Australia, Australia
| | - Robyn Lucas
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, Western Australia, Australia.,National Centre for Epidemiology and Population Health, Research School of Population Health, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Seyhan Yazar
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, Western Australia, Australia .,Single Cell and Computational Genomics, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
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15
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Hagen LA, Arnegard S, Kuchenbecker JA, Gilson SJ, Neitz M, Neitz J, Baraas RC. The association between L:M cone ratio, cone opsin genes and myopia susceptibility. Vision Res 2019; 162:20-28. [PMID: 31254532 PMCID: PMC7122956 DOI: 10.1016/j.visres.2019.06.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 11/16/2022]
Abstract
In syndromic forms of myopia caused by long (L) to middle (M) wavelength (L/M) interchange mutations, erroneous contrast signals from ON-bipolar cells activated by cones with different levels of opsin expression are suggested to make the eye susceptible to increased growth. This susceptibility is modulated by the L:M cone ratio. Here, we examined L and M opsin genes, L:M cone ratios and their association with common refractive errors in a population with low myopia prevalence. Cycloplegic autorefraction and ocular biometry were obtained for Norwegian genetically-confirmed normal trichromats. L:M cone ratios were estimated from spectral sensitivity functions measured with full-field ERG, after adjusting for individual differences in the wavelength of peak absorption deduced from cone opsin genetics. Mean L:M cone ratios and the frequency of alanine at L opsin position 180 were higher in males than what has been reported in males in populations with high myopia prevalence. High L:M cone ratios in females were associated with lower degree of myopia, and myopia was more frequent in females who were heterozygous for L opsin exon 3 haplotypes than in those who were homozygous. The results suggest that the L:M cone ratio, combined with milder versions of L opsin gene polymorphisms, may play a role in common myopia. This may in part explain the low myopia prevalence in Norwegian adolescents and why myopia prevalence was higher in females who were heterozygous for the L opsin exon 3 haplotype, since females are twice as likely to have genetic polymorphisms carried on the X-chromosome.
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Affiliation(s)
- Lene A Hagen
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Hasbergs vei 36, 3616 Kongsberg, Norway.
| | - Solveig Arnegard
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Hasbergs vei 36, 3616 Kongsberg, Norway.
| | - James A Kuchenbecker
- Department of Ophthalmology, University of Washington Medical School, Box 358058, 750 Republican Street, Building E Room, Seattle, WA 98109, United States
| | - Stuart J Gilson
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Hasbergs vei 36, 3616 Kongsberg, Norway.
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington Medical School, Box 358058, 750 Republican Street, Building E Room, Seattle, WA 98109, United States.
| | - Jay Neitz
- Department of Ophthalmology, University of Washington Medical School, Box 358058, 750 Republican Street, Building E Room, Seattle, WA 98109, United States.
| | - Rigmor C Baraas
- National Centre for Optics, Vision and Eye Care, Faculty of Health and Social Sciences, University of South-Eastern Norway, Hasbergs vei 36, 3616 Kongsberg, Norway.
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16
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Rucker F. Monochromatic and white light and the regulation of eye growth. Exp Eye Res 2019; 184:172-182. [PMID: 31018118 DOI: 10.1016/j.exer.2019.04.020] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/02/2019] [Accepted: 04/16/2019] [Indexed: 12/25/2022]
Abstract
Experiments employing monochromatic light have been used to investigate the role of longitudinal chromatic aberration (LCA) as possible signals for emmetropization for many years. LCA arising from the dispersion of light, causes differences in the focal length at different wavelengths and can impose defocus (wavelength defocus). Short-wavelength light focuses with a shorter focal length than long-wavelength light and, as such, would be expected to produce a smaller, more hyperopic eye. Emmetropization can respond to wavelength defocus since animals reared in monochromatic light adjust their refractive state relative to that measured in white light. In many species, animals reared in monochromatic light respond as predicted by wavelength defocus, becoming more hyperopic in blue light and more myopic in red light. However, tree shrews and rhesus monkey become more hyperopic in red light, and while tree shrews initially become more hyperopic in blue light, they later become more myopic. This review examines the experiments performed in monochromatic light and highlights the potential differences in protocols affecting the results, including experiment duration, circadian rhythm stimulation, light intensity, bandwidth, humoral factors and temporal sensitivity.
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Affiliation(s)
- Frances Rucker
- New England College of Optometry, 424 Beacon St, Boston, MA, 02115, USA.
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Chakraborty R, Yang V, Park HN, Landis EG, Dhakal S, Motz CT, Bergen MA, Iuvone PM, Pardue MT. Lack of cone mediated retinal function increases susceptibility to form-deprivation myopia in mice. Exp Eye Res 2018; 180:226-230. [PMID: 30605665 DOI: 10.1016/j.exer.2018.12.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/18/2018] [Accepted: 12/29/2018] [Indexed: 11/30/2022]
Abstract
Retinal photoreceptors are important in visual signaling for normal eye growth in animals. We used Gnat2cplf3/cplf3 (Gnat2-/-) mice, a genetic mouse model of cone dysfunction to investigate the influence of cone signaling in ocular refractive development and myopia susceptibility in mice. Refractive development under normal visual conditions was measured for Gnat2-/- and age-matched Gnat2+/+ mice, every 2 weeks from 4 to 14 weeks of age. Weekly measurements were performed on a separate cohort of mice that underwent monocular form-deprivation (FD) in the right eye from 4 weeks of age using head-mounted diffusers. Refraction, corneal curvature, and ocular biometrics were obtained using photorefraction, keratometry and optical coherence tomography, respectively. Retinas from FD mice were harvested, and analyzed for dopamine (DA) and 3,4-dihydroxyphenylacetate (DOPAC) using high-performance liquid chromatography. Under normal visual conditions, Gnat2+/+ and Gnat2-/- mice showed similar refractive error, axial length, and corneal radii across development (p > 0.05), indicating no significant effects of the Gnat2 mutation on normal ocular refractive development in mice. Three weeks of FD produced a significantly greater myopic shift in Gnat2-/- mice compared to Gnat2+/+ controls (-5.40 ± 1.33 D vs -2.28 ± 0.28 D, p = 0.042). Neither the Gnat2 mutation nor FD altered retinal levels of DA or DOPAC. Our results indicate that cone pathways needed for high acuity vision in primates are not as critical for normal refractive development in mice, and that both rods and cones contribute to visual signalling pathways needed to respond to FD in mammalian eyes.
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Affiliation(s)
- Ranjay Chakraborty
- Department of Ophthalmology, Emory University School of Medicine, 1365B Clifton Rd NE, Atlanta, GA, 30322, USA; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, 1670 Clairmont Rd, Decatur, GA, 30033, USA; College of Nursing and Health Sciences, Flinders University, Bedford Park, SA, 5001, Adelaide, Australia
| | - Victoria Yang
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, 1670 Clairmont Rd, Decatur, GA, 30033, USA
| | - Han Na Park
- Department of Ophthalmology, Emory University School of Medicine, 1365B Clifton Rd NE, Atlanta, GA, 30322, USA; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, 1670 Clairmont Rd, Decatur, GA, 30033, USA
| | - Erica G Landis
- Department of Ophthalmology, Emory University School of Medicine, 1365B Clifton Rd NE, Atlanta, GA, 30322, USA; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, 1670 Clairmont Rd, Decatur, GA, 30033, USA
| | - Susov Dhakal
- Department of Ophthalmology, Emory University School of Medicine, 1365B Clifton Rd NE, Atlanta, GA, 30322, USA
| | - Cara T Motz
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, 1670 Clairmont Rd, Decatur, GA, 30033, USA
| | - Michael A Bergen
- Department of Ophthalmology, Emory University School of Medicine, 1365B Clifton Rd NE, Atlanta, GA, 30322, USA; Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, 1670 Clairmont Rd, Decatur, GA, 30033, USA
| | - P Michael Iuvone
- Department of Ophthalmology, Emory University School of Medicine, 1365B Clifton Rd NE, Atlanta, GA, 30322, USA; Department of Pharmacology, Emory University School of Medicine, 1365B Clifton Rd NE, Atlanta, GA, 30322, USA
| | - Machelle T Pardue
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, 1670 Clairmont Rd, Decatur, GA, 30033, USA; Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Dr, Atlanta, GA, 30332, USA.
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Buena-Atienza E, Nasser F, Kohl S, Wissinger B. A 73,128 bp de novo deletion encompassing the OPN1LW/OPN1MW gene cluster in sporadic Blue Cone Monochromacy: a case report. BMC MEDICAL GENETICS 2018; 19:107. [PMID: 29940872 PMCID: PMC6019650 DOI: 10.1186/s12881-018-0623-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/12/2018] [Indexed: 01/04/2023]
Abstract
Background Blue Cone Monochromacy (BCM) is a rare congenital cone dysfunction disorder with X-linked recessive mode of inheritance. BCM is caused by mutations at the OPN1LW/MW cone opsin gene cluster including deletions of the locus control region (LCR) and/or parts of the gene cluster. We aimed at investigating the clinical presentation, genetic cause and inheritance underlying a sporadic case of BCM. Case presentation We report a 24-year-old male presenting with congenital photophobia, nystagmus and colour vision abnormalities. There was no history of retinal dystrophy in the family. Clinical diagnosis of BCM was supported by genetic investigations of the patient and his family members. Molecular genetic analysis of the OPN1LW/OPN1MW gene cluster revealed a novel deletion of about 73 kb in the patient encompassing the LCR. The deletion was absent in the X-chromosomes of both the mother and transmitting grandfather. Conclusions The present report provides the clinical findings and the genetic basis underlying a sporadic BCM case which is caused by a de novo deletion within the OPN1LW/MW gene cluster originating from the mother’s germline due to Alu-repeat mediated recombination. This is the first report of a de novo deletion resulting in BCM, highlighting the importance to consider BCM and perform genetic testing for this condition in male patients with cone dysfunction also in the absence of a positive family history.
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Affiliation(s)
- Elena Buena-Atienza
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany
| | - Fadi Nasser
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn 7, D-72076, Tuebingen, Germany.
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