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Ebrahimi M, Gharravi AM, Aliyari R, Emamian MH, Khabazkhoob M, Hashemi H, Fotouhi A. The association between iris color and refractive errors in children. Sci Rep 2024; 14:2192. [PMID: 38272946 PMCID: PMC10810802 DOI: 10.1038/s41598-024-52807-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 01/23/2024] [Indexed: 01/27/2024] Open
Abstract
This study aimed to evaluate the association between iris color and refractive errors in children aged 6-12 years. This cross-sectional study was based on data obtained from the first phase of the Shahroud Schoolchildren Eye Cohort Study. The target population was 6 to12 year-old students living in urban and rural areas. Iris colors were classified by comparing eye colors with close-up images of iris colors. Myopia was defined as a spherical equivalent (SE) ≤ - 0.5 diopter and hyperopia was defined as SE ≥ 2 diopter in cycloplegic refraction. The association of iris color with hyperopia and myopia was investigated by fitting two separate multiple logistic regression models adjusted for place of residence, age, sex, and times for outdoor activity and near work. Among the 5394 participates with the mean age of 9.7 year, the prevalence of myopia and hyperopia was 4.8% and 4.7% respectively. The number and proportion (in parentheses) of amber, light blue, light brown, dark brown, gray, green and hazel iris colors were 19(0.4%), 26(0.5%), 645(12.0%), 4517(83.7%), 4(0.1%), 59(1.1%), and 124(2.3%) respectively. Compared to dark brown, the odds ratios and 95% confidence intervals (in parentheses) of myopia were 4.8(1.2-18.7), 0.8(0.1-5.8), 1.0(0.7-1.5), 0.4(0.1-2.7) and 0.6(0.2-1.8) for amber, light blue, light brown, green and hazel iris colors in multiple logistic regression model. No significant association was observed between iris colors and hyperopia. This study shows that amber iris is significantly associated with higher odds of myopia. These children should be further monitored and examined. More studies with higher sample size in all iris colors are recommended.
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Affiliation(s)
- Mehrdad Ebrahimi
- Student Research Committee, School of Medicine, Shahroud University of Medical Sciences, Shahroud, Iran
| | | | - Roqayeh Aliyari
- Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Mohammad Hassan Emamian
- Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences, Shahroud, Iran.
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Akbar Fotouhi
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Li X, Holt RR, Keen CL, Morse LS, Zivkovic AM, Yiu G, Hackman RM. Potential roles of dietary zeaxanthin and lutein in macular health and function. Nutr Rev 2023; 81:670-683. [PMID: 36094616 DOI: 10.1093/nutrit/nuac076] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Lutein, zeaxanthin, and meso-zeaxanthin are three xanthophyll carotenoid pigments that selectively concentrate in the center of the retina. Humans cannot synthesize lutein and zeaxanthin, so these compounds must be obtained from the diet or supplements, with meso-zeaxanthin being converted from lutein in the macula. Xanthophylls are major components of macular pigments that protect the retina through the provision of oxidant defense and filtering of blue light. The accumulation of these three xanthophylls in the central macula can be quantified with non-invasive methods, such as macular pigment optical density (MPOD). MPOD serves as a useful tool for assessing risk for, and progression of, age-related macular degeneration, the third leading cause of blindness worldwide. Dietary surveys suggest that the dietary intakes of lutein and zeaxanthin are decreasing. In addition to low dietary intake, pregnancy and lactation may compromise the lutein and zeaxanthin status of both the mother and infant. Lutein is found in modest amounts in some orange- and yellow-colored vegetables, yellow corn products, and in egg yolks, but rich sources of zeaxanthin are not commonly consumed. Goji berries contain the highest known levels of zeaxanthin of any food, and regular intake of these bright red berries may help protect against the development of age-related macular degeneration through an increase in MPOD. The purpose of this review is to summarize the protective function of macular xanthophylls in the eye, speculate on the compounds' role in maternal and infant health, suggest the establishment of recommended dietary values for lutein and zeaxanthin, and introduce goji berries as a rich food source of zeaxanthin.
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Affiliation(s)
- Xiang Li
- are with the Department of Nutrition, UC Davis, Davis, California, USA
| | - Roberta R Holt
- are with the Department of Nutrition, UC Davis, Davis, California, USA
| | - Carl L Keen
- are with the Department of Nutrition, UC Davis, Davis, California, USA
- is with the Department of Internal Medicine, UC Davis, Sacramento, California, USA
| | - Lawrence S Morse
- are with the Department of Ophthalmology and Vision Science, UC Davis Medical Center, Sacramento, California, USA
| | - Angela M Zivkovic
- re with the Department of Nutrition, UC Davis, Davis, California, USA
| | - Glenn Yiu
- are with the Department of Ophthalmology and Vision Science, UC Davis Medical Center, Sacramento, California, USA
| | - Robert M Hackman
- are with the Department of Nutrition, UC Davis, Davis, California, USA
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Rahat MA, Akbar F, Rasool A, Ilyas M, Rakha A, Shams S, Jelani M, Bibi F, Shirah BH, Abdulkareem AA, Naseer MI, Israr M. Phenotypic Classification of Eye Colour and Developmental Validation of the Irisplex System on Population Living in Malakand Division, Pakistan. Biomedicines 2023; 11:biomedicines11041228. [PMID: 37189847 DOI: 10.3390/biomedicines11041228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 04/13/2023] [Accepted: 04/17/2023] [Indexed: 05/17/2023] Open
Abstract
The core objective of forensic DNA typing is developing DNA profiles from biological evidence for personal identification. The present study was designed to check the validation of the IrisPlex system and the Prevalence of eye colour in the Pakhtoon population residing within the Malakand Division. METHODS Eye colour digital photographs and buccal swab samples of 893 individuals of different age groups were collected. Multiplexed SNaPshot single base extension chemistry was used, and the genotypic results were analysed. Snapshot data were used for eye colour prediction through the IrisPlex and FROG-kb tool. RESULTS The results of the present study found brown eye colour to be the most prevalent eye colour in comparison to intermediate and blue coloured. Overall, individuals with brown-coloured eyes possess CT (46.84%) and TT (53.16%) genotypes. Blue eye-coloured individuals are solely of the CC genotype, while individuals of intermediate eye colour carry CT (45.15%) and CC (53.85%) genotypes in rs12913832 SNP in the HERC2 gene. It was also revealed that brown-coloured eyes individuals were dominant among all age groups followed by intermediate and blue. Statistical analysis between particular variables and eye colour showed a significant p-value (<0.05) for rs16891982 SNP in SLC45A2 gene, rs12913832 SNP in HERC2 gene, rs1393350 SNP in SLC45A2, districts and gender. The rest of the SNPs were non-significant with eye colour, respectively. The rs12896399 SNP and SNP rs1800407 were found significant with rs16891982 SNP. The result also demonstrated that the study group differs from the world population based on eye colour. The two eye colour prediction results were compared, and it was discovered that IrisPlex and FROG-Kb had similar higher prediction ratios for Brown and Blue eye colour. CONCLUSIONS The results of the current study revealed brown eye colour to be the most prevalent amongst members of the local population of Pakhtoon ethnicity in the Malakand Division of northern Pakistan. A set of contemporary human DNA samples with known phenotypes are used in this research to evaluate the custom panel's prediction accuracy. With the aid of this forensic test, DNA typing can be supplemented with details about the appearance of the person from whom the sample was taken in cases involving missing persons, ancient human remains, and trace samples. This study may be helpful for future population genetics and forensics studies.
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Affiliation(s)
- Murad Ali Rahat
- Centre for Biotechnology and Microbiology, University of Swat, Charbagh 19120, Pakistan
- Department of Forensic Sciences, University of Swat, Charbagh 19120, Pakistan
| | - Fazal Akbar
- Centre for Biotechnology and Microbiology, University of Swat, Charbagh 19120, Pakistan
| | - Akhtar Rasool
- Centre for Biotechnology and Microbiology, University of Swat, Charbagh 19120, Pakistan
| | - Muhammad Ilyas
- Centre for Omic Sciences, Islamia College University Peshawar, Peshawar 25120, Pakistan
| | - Allah Rakha
- Department of Forensic Sciences, University of Health Sciences, Lahore 54600, Pakistan
| | - Sulaiman Shams
- Department of Biochemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Musharraf Jelani
- Centre for Omic Sciences, Islamia College University Peshawar, Peshawar 25120, Pakistan
| | - Fehmida Bibi
- Special Infectious Agents Unit, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Bader H Shirah
- Department of Neuroscience, King Faisal Specialist Hospital & Research Centre, Jeddah 21589, Saudi Arabia
| | - Angham Abdulrhman Abdulkareem
- Faculty of Science, Department of Biochemistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Muhammad Imran Naseer
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Muhammad Israr
- Department of Forensic Sciences, University of Swat, Charbagh 19120, Pakistan
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Vural E, Hazar L, Çağlayan M, Çelebi ARC. Evaluation of choroidal thickness in light-coloured eyes. Eur J Ophthalmol 2021; 32:1636-1641. [PMID: 34218695 DOI: 10.1177/11206721211029470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The aim of this study was to determine whether iris colour is related to the choroidal thickness of healthy individuals. METHODS Healthy participants were divided into two groups. Group 1 had light-coloured eyes (blue and green), and group 2 had dark-coloured eyes (brown). The main outcome measures were iris thickness, subfoveal choroidal thickness and nasal and temporal choroidal thicknesses 500 µm away from the fovea. RESULTS Group 1 comprised 31 subjects with light-coloured eyes, and group 2 had 31 subjects with dark eyes. The mean ages of groups 1 and 2 were 26.7 ± 7.5 years and 24.1 ± 5.8 years, respectively (p = 0.14). The choroidal thicknesses of the subfoveal, nasal and temporal regions were 336.3 ± 52.1 µm, 321.9 ± 43.6 µm and 318.4 ± 49.2 µm, respectively, in group 1 and 396.5 ± 76.9 µm, 372 ± 79.3 µm and 379.6 ± 82.4 µm, respectively, in group 2. All the values in group 1 were statistically lower than those in group 2 (p = 0.001, p = 0.001 and p = 0.003, respectively). The iris thickness in group 1 (493.73 ± 95.44 µm) was thinner than in group 2 (524.61 ± 69.74 µm) but not statistically significant (p = 0.141). CONCLUSION The results showed that a thinner choroid can be seen in disease-free light-coloured eyes. The iris colour should be considered among the factors affecting the choroidal thickness, such as age, sex, race and refractive error.
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Affiliation(s)
- Esra Vural
- Department of Ophthalmology, Kayseri City Hospital, Kayseri, Turkey
| | - Leyla Hazar
- Department of Ophthalmology, Dicle University School of Medicine, Diyarbakır, Turkey
| | - Mehtap Çağlayan
- Department of Ophthalmology, Gazi Yaşargil Training and Research Hospital, Diyarbakır, Turkey
| | - Ali Rıza Cenk Çelebi
- Department of Ophthalmology, Acıbadem University, Faculty of Medicine, İstanbul, Turkey
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Pugazhendhi A, Hubbell M, Jairam P, Ambati B. Neovascular Macular Degeneration: A Review of Etiology, Risk Factors, and Recent Advances in Research and Therapy. Int J Mol Sci 2021; 22:1170. [PMID: 33504013 PMCID: PMC7866170 DOI: 10.3390/ijms22031170] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/11/2021] [Accepted: 01/19/2021] [Indexed: 12/14/2022] Open
Abstract
Neovascular age-related macular degeneration (exudative or wet AMD) is a prevalent, progressive retinal degenerative macular disease that is characterized by neovascularization of the choroid, mainly affecting the elderly population causing gradual vision impairment. Risk factors such as age, race, genetics, iris color, smoking, drinking, BMI, and diet all play a part in nvAMD's progression, with anti-vascular endothelial growth factor (anti-VEGF) therapy being the mainstay of treatment. Current therapeutic advancements slow the progression of the disease but do not cure or reverse its course. Newer therapies such as gene therapies, Rho-kinase inhibitors, and levodopa offer potential new targets for treatment.
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Affiliation(s)
- Arunbalaji Pugazhendhi
- Knights Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR 97403, USA; (A.P.); (M.H.)
| | - Margaret Hubbell
- Knights Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR 97403, USA; (A.P.); (M.H.)
| | - Pooja Jairam
- Vagelos College of Physicians & Surgeons, Columbia Irving Medical Center, Columbia University, New York, NY 10032, USA;
| | - Balamurali Ambati
- Knights Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR 97403, USA; (A.P.); (M.H.)
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Xu A, Chen C. Clinical application of ultra-widefield fundus autofluorescence. Int Ophthalmol 2020; 41:727-741. [PMID: 33040254 DOI: 10.1007/s10792-020-01609-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 10/01/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE To review the basic principles of ultra-widefield fundus autofluorescence (UWF-FAF) and discuss its clinical application for a variety of retinal and choroidal disorders. METHODS A systematic review of the PubMed database was performed using the search terms "ultra-widefield," "autofluorescence," "retinal disease" and "choroidal disease." RESULTS UWF-FAF imaging is a recently developed noninvasive retinal imaging modality with a wide imaging range that can locate peripheral fundus lesions that traditional fundus autofluorescence cannot. Multiple commercially available ultra-widefield imaging systems, including Heidelberg Spectralis and Optomap Ultra-Widefield systems, are available to the clinician. Imaging by UWF-FAF is more comprehensive; it can reflect the content and distribution of the predominant ocular fluorophore in retinal pigment epithelial cells and evaluate the metabolic status of RPE of various retinal and choroidal disorders. CONCLUSION UWF-FAF can detect abnormalities that traditional fundus autofluorescence cannot; therefore, it can be used to better elucidate disease pathogenesis, analyze genotype-phenotype correlations, diagnose and monitor disease.
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Affiliation(s)
- Amin Xu
- Department of Ophthalmology of Renmin Hospital of Wuhan University, No238, Jiefang Road, Wuhan, 430060, Hubei, China
| | - Changzheng Chen
- Department of Ophthalmology of Renmin Hospital of Wuhan University, No238, Jiefang Road, Wuhan, 430060, Hubei, China.
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Hashemi H, Pakzad R, Yekta A, Shokrollahzadeh F, Ostadimoghaddam H, Mahboubipour H, Khabazkhoob M. Distribution of iris color and its association with ocular diseases in a rural population of Iran. J Curr Ophthalmol 2018; 31:312-318. [PMID: 31528767 PMCID: PMC6742598 DOI: 10.1016/j.joco.2018.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/28/2018] [Accepted: 05/05/2018] [Indexed: 11/23/2022] Open
Abstract
Purpose To determine the distribution of iris color and its relationship with some ocular diseases in a rural population of Iran. Methods Two rural areas of the north and southwest of Iran were selected by a cross-sectional study using multi-stage cluster sampling. After selecting samples, the participants had an eye examination including measuring visual acuity, refraction, and Pentacam imaging. Then an eye examination for individuals was performed by slit-lamp. Results Out of 3851 invited people, 3314 participated in this study (participation rate, 86.05%). Dark brown [41.28%, confidence interval (CI) 95% = 31.88–50.68] and blue (0.99%, CI 95% = 0.57–1.41) were the most and the least type of iris colors among participants of this study. Compared to others, people with a dark iris have the biggest anterior chamber depth (ACD), angle and volume while central corneal thickness (CCT), keratometry and pupil were highest among people with a dark brown iris (P < 0.002). Considering the dark brown group as a base group, the chances of being afflicted to cataract among people with dark, light brown, green, and blue irises are 1.89 (CI 95% = 1.25–2.86), 1.53 (CI 95% = 1.17–2.01), 4.60 (CI 95% = 2.17–9.71), and 12.17 (CI 95% = 5.05–29.31), respectively. The chance of being afflicted to myopia among people with green irises and to hyperopia among people with blue irises were high (1.60, CI 95% = 1.08–2.36 and 3.20, CI 95% = 1.03–9.97, respectively). Conclusions Dark brown was the most prevalent iris color in rural areas of Iran. The index of cornea among people with dark and dark brown iris color is higher than other people, and people with light iris color are at a higher risk of developing eye disease such as cataract, corneal opacity, and refractive error. To determine this relationship and its usage for therapeutic and public health purposes, further studies are recommended.
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Affiliation(s)
- Hassan Hashemi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.,Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Reza Pakzad
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Abbasali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Hadi Ostadimoghaddam
- Refractive Errors Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hassan Mahboubipour
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Mehdi Khabazkhoob
- Department of Medical Surgical Nursing, School of Nursing and Midwifery, ShahidBeheshti University of Medical Sciences, Tehran, Iran
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Heiduschka P, Blitgen-Heinecke P, Tura A, Kokkinou D, Julien S, Hofmeister S, Bartz-Schmidt KU, Schraermeyer U. Melanin Precursor 5,6-Dihydroxyindol: Protective Effects and Cytotoxicity on Retinal Cells in vitro and in vivo. Toxicol Pathol 2016; 35:1030-8. [DOI: 10.1080/01926230701831358] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
5,6-Dihydroxyindole (DHI) is a melanin pigment precursor with antioxidant properties. In the light of a report about cytotoxicity of DHI, the aim of this study was to assess possible toxic effects of DHI on cells related to the eye, such as human ARPE-19 cells and mouse retinal explants. Moreover, DHI was tested on its effects on retinal function in vivo using electroretinography. We found cytotoxicity of DHI against ARPE-19 cells at 100 μM, but not at 10 μM. 10 μM DHI exhibited a slight, though not significant protective activity against UV-A damage in ARPE-19 cells. We found cytoprotection in cultured mouse retinas by 50 μM DHI or its diacetylated derivative 5,6-diacetoxyindole (DAI), respectively. In ERG measurements in vivo, amplitudes were decreased only slightly by 100 μM DHI compared to saline, whereas a better preservation of amplitudes was visible at 10 μM DHI, in particular with respect to cones. In histological sections, more cones were found at 10 μM DHI than at 100 μM DHI. As a conclusion, DHI shows a slight protective effect at 10 μM both in vitro and in vivo. At 100 μM, it shows a strong cytotoxicity in vitro, which is strongly reduced in vivo.
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Affiliation(s)
- Peter Heiduschka
- Section for Experimental Vitreoretinal Surgery, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076 Tübingen, Germany
- Steinbeis Transfer Centre for Pathology and Toxicology of the Eye, Schleichstr. 12/1, D-72076 Tübingen, Germany
| | - Petra Blitgen-Heinecke
- Section for Experimental Vitreoretinal Surgery, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076 Tübingen, Germany
- Steinbeis Transfer Centre for Pathology and Toxicology of the Eye, Schleichstr. 12/1, D-72076 Tübingen, Germany
| | - Aysegül Tura
- University Eye Hospital Dept. I, Schleichstr. 12, D-72076 Tübingen, Germany
| | - Despina Kokkinou
- Section for Experimental Vitreoretinal Surgery, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076 Tübingen, Germany
| | - Sylvie Julien
- Section for Experimental Vitreoretinal Surgery, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076 Tübingen, Germany
| | - Sabine Hofmeister
- Section for Experimental Vitreoretinal Surgery, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076 Tübingen, Germany
| | | | - Ulrich Schraermeyer
- Section for Experimental Vitreoretinal Surgery, University Eye Hospital Tübingen, Schleichstr. 12/1, D-72076 Tübingen, Germany
- Steinbeis Transfer Centre for Pathology and Toxicology of the Eye, Schleichstr. 12/1, D-72076 Tübingen, Germany
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Lambert NG, ElShelmani H, Singh MK, Mansergh FC, Wride MA, Padilla M, Keegan D, Hogg RE, Ambati BK. Risk factors and biomarkers of age-related macular degeneration. Prog Retin Eye Res 2016; 54:64-102. [PMID: 27156982 DOI: 10.1016/j.preteyeres.2016.04.003] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/01/2016] [Accepted: 04/12/2016] [Indexed: 02/03/2023]
Abstract
A biomarker can be a substance or structure measured in body parts, fluids or products that can affect or predict disease incidence. As age-related macular degeneration (AMD) is the leading cause of blindness in the developed world, much research and effort has been invested in the identification of different biomarkers to predict disease incidence, identify at risk individuals, elucidate causative pathophysiological etiologies, guide screening, monitoring and treatment parameters, and predict disease outcomes. To date, a host of genetic, environmental, proteomic, and cellular targets have been identified as both risk factors and potential biomarkers for AMD. Despite this, their use has been confined to research settings and has not yet crossed into the clinical arena. A greater understanding of these factors and their use as potential biomarkers for AMD can guide future research and clinical practice. This article will discuss known risk factors and novel, potential biomarkers of AMD in addition to their application in both academic and clinical settings.
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Affiliation(s)
- Nathan G Lambert
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
| | - Hanan ElShelmani
- Ocular Development and Neurobiology Research Group, Zoology Department, School of Natural Sciences, University of Dublin, Trinity College, Dublin 2, Ireland.
| | - Malkit K Singh
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
| | - Fiona C Mansergh
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
| | - Michael A Wride
- Ocular Development and Neurobiology Research Group, Zoology Department, School of Natural Sciences, University of Dublin, Trinity College, Dublin 2, Ireland.
| | - Maximilian Padilla
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
| | - David Keegan
- Mater Misericordia Hospital, Eccles St, Dublin 7, Ireland.
| | - Ruth E Hogg
- Centre for Experimental Medicine, Institute of Clinical Science Block A, Grosvenor Road, Belfast, Co.Antrim, Northern Ireland, UK.
| | - Balamurali K Ambati
- Ambati Lab, John A. Moran Eye Center, 65 Mario Capecchi Drive, Salt Lake City, UT, USA; Department of Ophthalmology & Visual Sciences, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, USA.
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Yung M, Klufas MA, Sarraf D. Clinical applications of fundus autofluorescence in retinal disease. Int J Retina Vitreous 2016; 2:12. [PMID: 27847630 PMCID: PMC5088473 DOI: 10.1186/s40942-016-0035-x] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/15/2016] [Indexed: 12/30/2022] Open
Abstract
Fundus autofluorescence (FAF) is a non-invasive retinal imaging modality used in clinical practice to provide a density map of lipofuscin, the predominant ocular fluorophore, in the retinal pigment epithelium. Multiple commercially available imaging systems, including the fundus camera, the confocal scanning laser ophthalmoscope, and the ultra-widefield imaging device, are available to the clinician. Each offers unique advantages for evaluating various retinal diseases. The clinical applications of FAF continue to expand. It is now an essential tool for evaluating age related macular degeneration, macular dystrophies, retinitis pigmentosa, white dot syndromes, retinal drug toxicities, and various other retinal disorders. FAF may detect abnormalities beyond those detected on funduscopic exam, fluorescein angiography, or optical coherence tomography, and can be used to elucidate disease pathogenesis, form genotype-phenotype correlations, diagnose and monitor disease, and evaluate novel therapies. Given its ease of use, non-invasive nature, and value in characterizing retinal disease, FAF enjoys increasing clinical relevance. This review summarizes common ocular fluorophores, imaging modalities, and FAF findings for a wide spectrum of retinal disorders.
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Affiliation(s)
- Madeline Yung
- Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles, CA 90095 USA
| | - Michael A. Klufas
- Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles, CA 90095 USA
| | - David Sarraf
- Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles, CA 90095 USA
- Greater Los Angeles VA Healthcare Center, Los Angeles, CA 90024 USA
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Sun HP, Lin Y, Pan CW. Iris color and associated pathological ocular complications: a review of epidemiologic studies. Int J Ophthalmol 2014; 7:872-8. [PMID: 25349810 DOI: 10.3980/j.issn.2222-3959.2014.05.25] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/08/2014] [Indexed: 11/02/2022] Open
Abstract
AIM To elucidate the associations of iris color with major eye diseases. METHODS A systematic search on Medline with coverage up to August 2013 was conducted. Assessment of the quality of studies based on their levels of evidence was in accordance with the Centre for Evidence-Based Medicine, Oxford, United Kingdom. RESULTS A relationship between darker iris color and an increased risk of age-related cataract has been reported from cross-sectional studies and prospective cohort studies. There was no consistent evidence supporting a major role of iris color in the development or progression of age-related macular degeneration. The association of iris color with ocular uveal melanoma has been confirmed by a meta-analysis of observational studies previously. The etiologic synergism between light iris color and environmental exposure such as UV the exposure of UV radiation was found. There were no studies evaluating the refractive associations with iris color but there may be a possible link between iris color and myopia. CONCLUSION Darker iris color is associated with an increased risk of cataract and a reduced risk of ocular uveal melanoma. The association of iris color with age-related macular degeneration is not confirmed. Ophthalmologists should be aware that the risk of ocular disorders appears to vary by differences in iris color.
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Affiliation(s)
- Hong-Peng Sun
- School of Public Health, Medical College of Soochow University, Suzhou 215123, Jiangsu Province, China
| | - Yi Lin
- Department of Public Health, Faculty of Medicine and Health Sciences, Ghent University, Ghent 9000, Belgium
| | - Chen-Wei Pan
- School of Public Health, Medical College of Soochow University, Suzhou 215123, Jiangsu Province, China ; Singapore Eye Research Institute, Singapore 168751, Singapore
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Meng W, Butterworth J, Calvas P, Malecaze F. Myopia and iris colour: A possible connection? Med Hypotheses 2012; 78:778-80. [DOI: 10.1016/j.mehy.2012.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 03/06/2012] [Indexed: 10/28/2022]
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Hashemi H, Yazdani K, Khabazkhoob M, Mehravaran S, Mohammad K, Fotouhi A. Distribution of photopic pupil diameter in the Tehran eye study. Curr Eye Res 2009; 34:378-85. [PMID: 19401881 DOI: 10.1080/02713680902853327] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE To determine the photopic pupil diameter and its determinants in a sample derived from a population-based survey in Tehran. METHODS In a cross-sectional study with a stratified random cluster sampling approach, 410 people age 14 years and over were selected from those residing in the first four municipality districts of Tehran after applying exclusion criteria, and 800 eyes (399 right eyes and 401 left eyes) were examined with the Orbscan II. The main outcome measure was the mean pupil diameter under photopic conditions, and possible correlations with potential determinants were evaluated through linear regression analyses. The design effect of a cluster sampling approach was observed and adjusted for. RESULTS The mean age of the participants was 40.6 +/- 16.8 years and 38.8% were male. The mean photopic pupil diameter (PPD) was 3.70 mm (range 2.30 to 5.10; 95% confidence interval (CI) 3.62 to 3.78). The mean PPD was 3.67 mm (95% CI, 3.54 to 3.81) in men and 3.72 mm (95% CI, 3.63 to 3.81) in women (p = 0.481). There was a significant reduction of 0.021 mm in PPD per year of aging (r = -0.49, p < 0.001). There was also a significant inverse correlation between PPD and spherical equivalent (r = -0.12, p = 0.034), while there was 0.66-mm increase in PPD with every 1.0-mm increase in the anterior chamber depth (ACD) (p < 0.001). Anisocoria, defined as a pupil diameter difference more than 0.4 mm between two eyes, was observed in 12.2% of the study population. CONCLUSION While the mean PPD measured with the Orbscan II was 3.70 mm in a sample derived from a population-based survey in Tehran, the scarcity of similar studies and reports concerning the pupil diameter measured with the Orbscan II makes it difficult to draw eligible comparisons. The pupil diameter has reverse correlations with age and spherical equivalent, a direct correlation with ACD, but is not correlated with gender.
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Affiliation(s)
- Hassan Hashemi
- Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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15
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Abstract
PURPOSE To assess the estimate prevalence and risk factors for age-related maculopathy (ARM) in Seoul, Korea. PATIENTS AND METHODS We examined 9,530 subjects with, 40 years of age or older between January 2006 and December 2006 in Seoul, Korea. Subjects underwent fundus photography, clinical examinations (including blood analyses), and completed detailed questionnaires. Fundus images were graded according to definitions from the Wisconsin Age-Related Maculopathy Grading System. RESULTS ARM was present in 235 subjects, corresponding to an estimate prevalence of 2.46%. Hepatitis B infection (positive status for HBsAg and HBcAb), serum triglyceride levels and high density lipoprotein levels remained as significant risk factors after age-adjustment. Multivariate analyses showed that the prevalence of ARM was significantly higher in older subjects [odds ratio (OR) 1.134; 95% CI 1.114-1.154] and those who were seropositive for hepatitis B surface antigen (OR 2.566; 95% CI 1.519-4.335). CONCLUSION The estimated prevalence of ARM was 2.46%. Age and hepatitis B infection may increase the risk of ARM.
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Affiliation(s)
- Mi In Roh
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
| | - Ji Hyun Kim
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
| | - Suk Ho Byeon
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
| | - Hyoung Jun Koh
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
| | - Sung Chul Lee
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
| | - Oh Woong Kwon
- Department of Ophthalmology, The Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
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Zadlo A, Rozanowska MB, Burke JM, Sarna TJ. Photobleaching of retinal pigment epithelium melanosomes reduces their ability to inhibit iron-induced peroxidation of lipids. ACTA ACUST UNITED AC 2007; 20:52-60. [PMID: 17250548 DOI: 10.1111/j.1600-0749.2006.00350.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Melanin in the human retinal pigment epithelium (RPE) is believed to play an important photoprotective role. However, unlike in skin, melanosomes in the RPE are rather long-lived organelles, which increases their risk of modifications resulting from significant fluxes of light and high oxygen tension. In this work, we subjected purified bovine RPE melanosomes to prolonged aerobic exposure with intense visible and near ultraviolet radiation and studied the effects of irradiation on the melanosome's capacity to inhibit peroxidation of lipids induced by iron/ascorbate. We found that control, untreated melanosomes show a concentration-dependent inhibition of the accumulation of lipid hydroperoxides and the accompanying consumption of oxygen, but photolysed melanosomes lose their antioxidant efficiency and even became prooxidant. The prooxidant action of partially photobleached melanosomes was observed for pigment granules with a melanin content reduced by about 50% compared with untreated melanosomes, as determined by electron spin resonance spectroscopy. We have previously shown that a similar loss in the content of the RPE melanin occurs during human lifetime, which may suggest that the normal antioxidant properties of human RPE melanin become compromised with aging.
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Affiliation(s)
- Andrzej Zadlo
- Department of Biophysics, Jagiellonian University, Krakow, Poland
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Abstract
In this article, we review the current state of knowledge concerning the physical and chemical properties of the eumelanin pigment. We examine properties related to its photoprotective functionality, and draw the crucial link between fundamental molecular structure and observable macroscopic behaviour. Where necessary, we also briefly review certain aspects of the pheomelanin literature to draw relevant comparison. A full understanding of melanin function, and indeed its role in retarding or promoting the disease state, can only be obtained through a full mapping of key structure-property relationships in the main pigment types. We are engaged in such an endeavor for the case of eumelanin.
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Affiliation(s)
- Paul Meredith
- Soft Condensed Matter Physics Group, School of Physical Sciences, University of Queensland, Brisbane, Australia
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Kokkinou D, Kasper HU, Schwarz T, Bartz-Schmidt KU, Schraermeyer U. Zinc uptake and storage: the role of fundus pigmentation. Graefes Arch Clin Exp Ophthalmol 2005; 243:1050-5. [PMID: 15906061 DOI: 10.1007/s00417-005-1197-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2005] [Accepted: 02/23/2005] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Age-related macular degeneration (AMD) is associated with lower melanin pigmentation and is more prevalent among the elderly Caucasian population than among Africans. A correlation between light iris colour, fundus pigmentation and the incidence of AMD is reported. Moreover, melanin represents the main storage of zinc in the eye. Zinc enhances antioxidant capacity through its function as a cofactor of important enzymes or by influencing gene expression of regulatory elements in the eye. In this study, we investigated the uptake and storage of zinc in the human choroid/retinal pigment epithelium (RPE) complexes in dependence on the fundus pigmentation as judged by the iris colour. MATERIAL AND METHODS Choroid/RPE complexes of blue and brown human eyes were used. Tissues without any substitution served as controls. Specimens from choroid/RPE complexes were incubated with 100 microM zinc chloride for 24 h. After incubation, pieces of the complexes were stored to investigate the uptake of zinc. The rest of the tissues were kept for 3 and 7 days in culture medium (DMEM) for storage examination. The concentration of zinc was measured by inductively coupled plasma mass spectrometry. RESULTS After 24 h of zinc treatment the concentration of zinc in the choroid/RPE complexes of blue eyes was not significantly increased. The concentration of zinc in highly pigmented tissues (brown eyes) was increased by the factor 5.1 after 24 h and remained at high levels after 3 days (factor 4.4) and 7 days (factor 2.8). CONCLUSIONS Zinc uptake in the choroid/RPE complex correlates to the iris colour. Alterations of the degree of iris pigmentation result in differences of zinc uptake and storage in the choroids. A potential protective role of zinc may be more prominent in dark- than in light-coloured eyes.
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Affiliation(s)
- Despina Kokkinou
- Section of Experimental Vitreoretinal Surgery, University of Tuebingen, Schleichstrasse 12/1, 72076, Tuebingen, Germany.
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Kokkinou D, Kasper HU, Bartz-Schmidt KU, Schraermeyer U. The Pigmentation of Human Iris Influences the Uptake and Storing of Zinc. ACTA ACUST UNITED AC 2004; 17:515-8. [PMID: 15357838 DOI: 10.1111/j.1600-0749.2004.00177.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Age-related macular degeneration (AMD) is more prevalent among the elderly Caucasians than in Africans. A significant association between light iris colour, fundus pigmentation and incidence of AMD is reported, suggesting a possible correlation with melanin pigment. Zinc is known to bind to melanin in pigmented tissues and to enhance antioxidant capacity by function as a cofactor or gene expression factor of antioxidant enzymes in the eye. In this in vitro study, we investigated the uptake and storage of zinc in human irides. Irides of blue and brown human eyes were used. The number of melanocytes was measured. Tissues without any treatment served as controls. The irides were incubated with 100 microM zinc chloride in culture medium for 24 h. Specimens of the tissues were stored for the uptake examination. The remained pieces were further incubated for 3 and 7 d to investigate the storage of zinc. The concentration of zinc was measured by inductively coupled plasma mass spectrometry (ICP-MS). Melanocytes count was significantly higher in the brown tissues (P < 0.0001). Zinc concentration of blue coloured irides after 24 h zinc treatment was close to the controls. We did not observe any significant storing. In contrast, the concentration of zinc in brown irides was significantly increased after 24 h (P < or = 0.01) and remained at a high level for 7 d. The uptake of zinc is likely dependent on the amount of pigmentation in human iris. Therefore, we assume that in patients suffering from AMD the degree of pigmentation of the irides and eventually fundi should be under consideration when the patients are treated with zinc supplementation.
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Affiliation(s)
- Despina Kokkinou
- Section of Experimental Vitreoretinal Surgery, University of Tuebingen, Schleichstr. 12/1, 72076 Tuebingen, Germany.
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