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GCABASHE NONKULULEKOM, MOODLEY VANESSARAQUEL, HANSRAJ REKHA. Prevalence and clinical profile of keratoconus in patients presenting at a provincial hospital in KwaZulu, Natal, South Africa: A case study. J Public Health Afr 2023; 14:2356. [PMID: 37942062 PMCID: PMC10628798 DOI: 10.4081/jphia.2023.2356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/16/2022] [Indexed: 11/10/2023] Open
Abstract
Keratoconus (KC) is a progressive, asymmetrical corneal disease, characterized by stromal thinning that leads to distortion, causing vision loss. The visual loss is secondary to corneal scarring, irregular astigmatism, and myopia. The prevalence of KC has been reported to differ in different parts of the world. The study aimed to determine the prevalence and profile of patients with KC presenting to a provincial hospital in KwaZulu-Natal, South Africa. A retrospective study design was used to review 412 clinical records of patients attending the McCord Provincial Eye Hospital (MPEH) during a five-year period (2016-2020). Data on age, race, refraction, clinical profile, treatment plan, and diagnosis were ascertained. The prevalence of KC in MPEH was found to be 13.7% with a mean age of 24.7±7.94 years. Black African and females had a higher frequency of KC compared to males and other ethnic groups. Most of the patients presented with a severe stage of KC and referral was the most common management. Central corneal thinning and Munson's sign were the most prevalent clinical signs. There was no statistically significant difference between the worse and better eye when comparing the clinical signs. The prevalence and clinical profile of patients with KC in this study was similar to that reported by previous studies and more in Blacks and females. Population based epidemiological studies are needed to determine the prevalence of KC in South Africa to enable early clinical interventions.
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Affiliation(s)
- NONKULULEKO M. GCABASHE
- Discipline of Optometry, School of Health Science, University of KwaZulu-Natal, Durban, South Africa
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Kanclerz P, Przewłócka K, Toprak I, Alio J. The prevalence of keratoconus in northern Poland: A cross-sectional study of patients from a primary healthcare practice. Cont Lens Anterior Eye 2023; 46:101846. [PMID: 37117129 DOI: 10.1016/j.clae.2023.101846] [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: 12/22/2022] [Revised: 04/13/2023] [Accepted: 04/16/2023] [Indexed: 04/30/2023]
Abstract
INTRODUCTION Keratoconus is defined as central and/or paracentral corneal thinning and steepening with consequent irregular astigmatism. To date, no prospective study has reported its prevalence in Central Europe. This study aimed to evaluate the prevalence of keratoconus assessed with Scheimpflug imaging in a profile of general medicine practice in Poland. METHODS This cross-sectional study collected data by inviting all patients aged 10-80 years subscribed to a single general practitioner in the Elbląg area, Poland. Corneal measurements were performed using a rotating Scheimpflug corneal tomography system. Three masked examiners established the diagnosis of keratoconus in the right or left eye. Fleiss' kappa coefficient (κ) was used to qualitatively analyze the interexaminer agreement. RESULTS Of 1,705 patients invited to the study, 771 agreed to participate (45.2%). The mean age of the 728 patients (60.6% female and 39.4% male) with gradable images in at least one eye was 53.6 ± 16.5 years. All of the examiners classified the same four cases as keratoconus (0.549%, 549 per 100,000, 95% confidence interval 150 to 1,400 per 100,000), of which two were bilateral. Fleiss' kappa showed almost perfect agreement among the three examiners regarding the diagnostic decision (κ = 0.784, 95% confidence interval 0.750 to 0.817, p < 0.001). The keratoconus cases were all women (p = 0.106), aged 48, 69, 70, and 71 years old. CONCLUSION The prevalence of keratoconus in this area was higher than that previously demonstrated in many European countries. Underestimation of the prevalence has been postulated but never demonstrated.
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Affiliation(s)
- Piotr Kanclerz
- Department of Ophthalmology, Hygeia Clinic, Gdańsk, Poland; Helsinki Retina Research Group, University of Helsinki, Finland.
| | | | - Ibrahim Toprak
- Department of Ophthalmology, Faculty of Medicine, Pamukkale University, Denizli, Turkey
| | - Jorge Alio
- Vissum Corporation, Avda de Denia S/N 03015, Alicante, Spain
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Jaskiewicz K, Maleszka-Kurpiel M, Michalski A, Ploski R, Rydzanicz M, Gajecka M. Non-allergic eye rubbing is a major behavioral risk factor for keratoconus. PLoS One 2023; 18:e0284454. [PMID: 37053215 PMCID: PMC10101517 DOI: 10.1371/journal.pone.0284454] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 04/01/2023] [Indexed: 04/14/2023] Open
Abstract
Since the environmental, behavioral, and socioeconomic factors in the etiology of keratoconus (KTCN) remain poorly understood, we characterized them as features influencing KTCN phenotype, and especially affecting the corneal epithelium (CE). In this case-control study, 118 KTCN patients and 73 controls were clinically examined and the Questionnaire covering the aforementioned aspects was completed and then statistically elaborated. Selected KTCN-specific findings were correlated with the outcomes of the RNA-seq assessment of the CE samples. Male sex, eye rubbing, time of using a computer after work, and dust in the working environment, were the substantial KTCN risk factors identified in multivariate analysis, with ORs of 8.66, 7.36, 2.35, and 5.25, respectively. Analyses for genes whose expression in the CE was correlated with the eye rubbing manner showed the enrichment in apoptosis (TP53, BCL2L1), chaperon-related (TLN1, CTDSP2, SRPRA), unfolded protein response (NFYA, TLN1, CTDSP2, SRPRA), cell adhesion (TGFBI, PTPN1, PDPK1), and cellular stress (TFDP1, SRPRA, CAPZB) pathways. Genes whose expression was extrapolated to the allergy status didn't contribute to IgE-related or other inflammatory pathways. Presented findings support the hypothesis of chronic mechanical corneal trauma in KTCN. Eye-rubbing causes CE damage and triggers cellular stress which through its influence on cell apoptosis, migration, and adhesion affects the KTCN phenotype.
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Affiliation(s)
| | - Magdalena Maleszka-Kurpiel
- Optegra Eye Health Care Clinic in Poznan, Poznan, Poland
- Chair of Ophthalmology and Optometry, Poznan University of Medical Sciences, Poznan, Poland
| | - Andrzej Michalski
- Chair of Ophthalmology and Optometry, Poznan University of Medical Sciences, Poznan, Poland
| | - Rafal Ploski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | | | - Marzena Gajecka
- Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
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Results of the Pinhole Test Correlate with Hybrid Contact Lens Visual Acuity in Patients with Visual Impairment due to Corneal Diseases. J Ophthalmol 2022; 2022:4932856. [PMID: 35783341 PMCID: PMC9249474 DOI: 10.1155/2022/4932856] [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: 04/13/2022] [Accepted: 06/03/2022] [Indexed: 11/18/2022] Open
Abstract
Introduction. Trial rigid lens fitting is considered the best approach to determine whether the correction of residual defocus and irregular astigmatism might improve the visual acuity in patients with corneal disorders including keratoconus. This study aimed to analyze the correlation between hybrid lenses and pinhole visual acuity (VA). Methods. Patients undergoing hybrid contact lens fitting at the Hygeia Clinic, Poland, were included. The VA of each patient was assessed as decimal Snellen fractions under the following conditions: (i) uncorrected VA, (ii) VA with spherocylindrical correction (i.e., corrected distance VA), (iii) VA with a single 1.2 mm pinhole occluder, and (iv) VA with the best-fitted hybrid contact lens. Pearson’s correlation coefficient r was used to assess correlations among variables. Results. This study involved 29 eyes of 19 patients, mainly with advanced keratoconus. The uncorrected VA was 0.11 ± 0.10. The pinhole test provided significantly improved VA over corrected distance VA (0.51 ± 0.29 vs. 0.31 ± 0.20, respectively;
). Similarly, the fitted hybrid contact lenses provided improved VA over corrected distance VA (0.66 ± 0.26 vs. 0.31 ± 0.20, respectively;
). The pinhole VA was strongly correlated with the hybrid contact lens VA (r = 0.8135; 95% CI: 0.61–0.92;
). The improvement in the pinhole test over corrected distance VA was moderately correlated with the improvement with the fitted lens over corrected distance VA (r = 0.6269; 95% confidence interval (CI): 0.32–0.80;
). Conclusions. A significant improvement in VA with the pinhole test is a simple predictor of general improvement with hybrid contact lenses. The pinhole test should be used in patients with corneal diseases such as keratoconus to determine whether optical aberrations associated with the disease cause their visual impairment.
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Prevalence of keratoconus in refractive surgery practice population in North Macedonia. Int Ophthalmol 2022; 42:3191-3198. [PMID: 35538254 DOI: 10.1007/s10792-022-02319-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE To determine the prevalence of keratoconus (KC) in relation to ethnicity in a group of people who consulted an ophthalmological care institution seeking for refractive surgery in N. Macedonia. METHODS This was a cross-sectional, interventional retrospective study. Chart reviews were performed for all new patients attending between January 2016 and January 2020 at the Sistina Ophthalmology Hospital in Skopje. All patients were screened; KC diagnosis and classification were based on the corneal topography. Ethnicity and gender classifications were according to patients' self-opinions. RESULTS A total of 2812 patients charts reviewed. The mean age was 31.71 years (SD ± 9.73), and 1209 (43%) were male. A total of 2050 (72.9%) declared themselves as Macedonians, 649 (23.1%) Albanians, 76 (2.7%) Turks and 37 (1.3%) in other ethnicities. Differences in age between the ethnic groups were statistically significant (x2 = 90.225, p < 0.001). KC was diagnosed in 343 patients (12.2%), while 9 (0.7%) were KC suspects and 6(0.21%) presented pellucid marginal degeneration. KC was more frequent in males (n = 246, 71.7% of total) and skewed toward younger patients. Increasing patients' age decreased the odds of KC diagnosis by 3.7% (95% CI 1.8%-4.4%) per annum. Males were four times more likely to be diagnosed with KC (AOR = 4.01; 95% CI 3.12-5.16). In comparison with Macedonian patients, Turks were more likely to be diagnosed with KC (AOR = 4.09; 95% CI 2.47-6.78). There was no difference between Macedonians and Albanians (p = 0.08). CONCLUSION The prevalence of KC at a refractive surgery practice in N. Macedonia is much higher compared with general population (6.8/100,000) and similar to the prevalence in Middle East Asia. Nationwide screening programs are needed to diagnose the disease earlier.
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Song M, Fang QY, Seth I, Baird PN, Daniell MD, Sahebjada S. Non-genetic risk factors for keratoconus. Clin Exp Optom 2022; 106:362-372. [PMID: 35504720 DOI: 10.1080/08164622.2022.2062222] [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: 10/18/2022] Open
Abstract
Keratoconus is a complex and multifactorial disease and its exact aetiology remains unknown. This current study examined the important environmental risk factors and their association with keratoconus. This study was registered in the PROSPERO International Prospective Register of systematic reviews under registration number CRD42021256792 in 2021. Scopus, Web of Science, PubMed, and Cochrane CENTRAL databases were searched for all relevant articles published from 1 January 1900 to 31 July 2021. National Institutes of Health Quality Assessment Tool was used to assess the methodological quality of the studies. The assessment for statistical heterogeneity was assessed using the Z-statistics on RevMan v5.4. P-value of <0.05 was considered as statistically significant and I2 < 25% as homogenous. Thirty studies were included in this meta-analysis. Pooled odds ratio was calculated with 95% CI. The pooled odds ratio (OR) of eye rubbing, atopy, asthma, and eczema was 3.64 (95% CI, 2.02, 6.57), 1.90 (95% CI, 1.22, 2.94), 1.36 (95% CI, 1.15, 1.61) and 1.90 (95% CI, 1.22, 2.94), respectively. The OR for diabetes was 0.86 (95% CI 0.73, 1.02), and use of sunglasses, contact lens, allergic conjunctivitis, side sleep position and prone sleep position was 0.40 (95% CI, 0.16, 0.99), 1.68 (0.70, 4.00), 2.24 (95% CI, 0.68, 7.36), 3.81 (95% CI, 0.31, 46.23), 12.76 (95% CI, 0.27, 598.58), respectively. Twenty studies were considered to be of high quality, nine to be moderate and one to be low. Environmental risk factors have been identified to play a role in the susceptibility of keratoconus. However, further large-scale longitudinal studies are needed to understand the mechanisms between environmental risk factors and keratoconus.
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Affiliation(s)
- Minji Song
- Centre for Eye Research Australia, Melbourne, Australia
| | - Qing Yi Fang
- Centre for Eye Research Australia, Melbourne, Australia
| | - Ishith Seth
- Centre for Eye Research Australia, Melbourne, Australia
| | - Paul N Baird
- Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Australia
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Santodomingo-Rubido J, Carracedo G, Suzaki A, Villa-Collar C, Vincent SJ, Wolffsohn JS. Keratoconus: An updated review. Cont Lens Anterior Eye 2022; 45:101559. [PMID: 34991971 DOI: 10.1016/j.clae.2021.101559] [Citation(s) in RCA: 168] [Impact Index Per Article: 84.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/23/2021] [Accepted: 12/12/2021] [Indexed: 02/06/2023]
Abstract
Keratoconus is a bilateral and asymmetric disease which results in progressive thinning and steeping of the cornea leading to irregular astigmatism and decreased visual acuity. Traditionally, the condition has been described as a noninflammatory disease; however, more recently it has been associated with ocular inflammation. Keratoconus normally develops in the second and third decades of life and progresses until the fourth decade. The condition affects all ethnicities and both sexes. The prevalence and incidence rates of keratoconus have been estimated to be between 0.2 and 4,790 per 100,000 persons and 1.5 and 25 cases per 100,000 persons/year, respectively, with highest rates typically occurring in 20- to 30-year-olds and Middle Eastern and Asian ethnicities. Progressive stromal thinning, rupture of the anterior limiting membrane, and subsequent ectasia of the central/paracentral cornea are the most commonly observed histopathological findings. A family history of keratoconus, eye rubbing, eczema, asthma, and allergy are risk factors for developing keratoconus. Detecting keratoconus in its earliest stages remains a challenge. Corneal topography is the primary diagnostic tool for keratoconus detection. In incipient cases, however, the use of a single parameter to diagnose keratoconus is insufficient, and in addition to corneal topography, corneal pachymetry and higher order aberration data are now commonly used. Keratoconus severity and progression may be classified based on morphological features and disease evolution, ocular signs, and index-based systems. Keratoconus treatment varies depending on disease severity and progression. Mild cases are typically treated with spectacles, moderate cases with contact lenses, while severe cases that cannot be managed with scleral contact lenses may require corneal surgery. Mild to moderate cases of progressive keratoconus may also be treated surgically, most commonly with corneal cross-linking. This article provides an updated review on the definition, epidemiology, histopathology, aetiology and pathogenesis, clinical features, detection, classification, and management and treatment strategies for keratoconus.
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Affiliation(s)
| | - Gonzalo Carracedo
- Department of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Asaki Suzaki
- Clinical Research and Development Center, Menicon Co., Ltd., Nagoya, Japan
| | - Cesar Villa-Collar
- Department of Pharmacy, Biotechnology, Nutrition, Optics and Optometry, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Madrid, Spain
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Centre for Vision and Eye Research, Queensland University of Technology, Brisbane, Australia
| | - James S Wolffsohn
- School of optometry, Health and Life Sciences, Aston University, Birmingham B4 7ET, United Kingdom
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Gokul A, Ziaei M, Mathan JJ, Han JV, Misra SL, Patel DV, McGhee CNJ. The Aotearoa Research Into Keratoconus Study: Geographic Distribution, Demographics, and Clinical Characteristics of Keratoconus in New Zealand. Cornea 2022; 41:16-22. [PMID: 33630812 DOI: 10.1097/ico.0000000000002672] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/06/2020] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the epidemiologic, demographic, and basic clinical characteristics of individuals with keratoconus managed by optometrists in New Zealand (NZ)/Aotearoa. METHODS A prospective, longitudinal, nationwide, survey protocol was completed for every patient with keratoconus who underwent a consultation with participating optometrists in a 2-year period. Data for each patient included date of birth, sex, self-reported ethnicity, new or previous diagnosis, uncorrected (UCVA) and best-corrected visual acuity (BCVA), type of refractive correction required to obtain BCVA and keratometric readings obtained using keratometry or computerized topography. RESULTS One thousand eight hundred sixty-nine cases were identified, with a mean age of 41.0 ± 15.7 years, 56.4% being men, and 87.3% with previous diagnosis. The distribution of cases was skewed toward Auckland (41.6%), Waikato (21.3%), Wellington (16.8%), and Bay of Plenty (13.3%). Self-reported ethnicities were predominantly NZ European (54.4%), Māori (24.7%), and Pacific Peoples (15.5%), disproportionate to the general population profile (74.0%, 14.9%, and 7.4% respectively). Most eyes (64.3%) were managed with rigid contact lenses (corneal lens in 34.2%). The mean K-mean was 49.0 ± 5.7 D. The mean UCVA was 6/42 and BCVA was 6/9. Māori and Pacific Peoples had both the highest K-mean and proportions of eyes graded stage IV on the Amsler-Krumeich scale. CONCLUSIONS The results indicate that keratoconus is relatively common in NZ with at least 1869 patients managed by optometrists in 2 years. Most eyes had mild to moderate disease; however, Māori and Pacific Peoples seem to have greater disease severity. An ethnic predilection is apparent, with Māori and Pacific Peoples overrepresented relative to their population proportions, reinforcing a long-held clinical suspicion.
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Affiliation(s)
- Akilesh Gokul
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Gokul A, Krishnan T, Emanuel PO, Saunders M, Mcghee CN. Persisting extreme acute corneal hydrops with a giant intrastromal cleft secondary to keratoconus. Clin Exp Optom 2021; 98:483-6. [DOI: 10.1111/cxo.12260] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/21/2014] [Accepted: 11/06/2014] [Indexed: 11/26/2022] Open
Affiliation(s)
- Akilesh Gokul
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Thiyaga Krishnan
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Patrick O Emanuel
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Mark Saunders
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Charles Nj Mcghee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
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Vellara HR, Patel DV. Biomechanical properties of the keratoconic cornea: a review. Clin Exp Optom 2021; 98:31-8. [DOI: 10.1111/cxo.12211] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 06/12/2014] [Accepted: 06/21/2014] [Indexed: 11/26/2022] Open
Affiliation(s)
- Hans R Vellara
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
| | - Dipika V Patel
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
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Prevalence and risk factors for keratoconus in a university-based population in Turkey. J Cataract Refract Surg 2021; 47:1524-1529. [PMID: 33929805 DOI: 10.1097/j.jcrs.0000000000000669] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/29/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE This study aimed to determine the prevalence of keratoconus (KC) in the students and faculty members (aged ≥18 and ≤30 years) studying/working at the Medical and Health Sciences faculties of Eskişehir Osmangazi University. SETTING Eskişehir Osmangazi University. DESIGN Prevalence study. METHODS Subjects were randomly selected to undergo KC screening using a proportional stratified sampling method. Out of the 648 invited subjects, 585 (90.3%) responded to the invitation. The demographic data, medical/family history and habits of the subjects were collected using a standardized questionnaire. Subjects were classified as KC, ectasia susceptibility, and normal based on the corneal tomography. The chi-square and Kruskal-Wallis tests were used for the analysis of categorical variables and parametric values, respectively. Risk factors for KC were determined using logistic regression analysis. RESULTS The prevalence of KC was 2,393/100,000 (2.4%, 95% CI: 1.3%-4%), whereas that of ectasia susceptibility was 1,538/100,000 (1.5%, 95% CI: 0.7%-2.9%). Although the prevalence was much higher in male (4%, 95% CI: 1.7%-7.7%) than in female (1.6%, 95% CI: 1.1%-4.4%) the difference was not statistically significant (p=0.09). The majority (78.6%, n=11) of KC patients were unaware of their disease. Eye rubbing (OR:3.53, p=0.024) and consanguineous marriage (OR:12.87, p=0.032) were independent risk factors for KC. CONCLUSION This is the first population-based KC prevalence study in a randomized sample conducted in Turkey. The prevalence of KC in Turkey was much higher than in European countries but similar to neighboring countries in the Middle East. Eye rubbing and history of consanguineous marriage were significant risk factors.
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Jurkiewicz T, Marty AS. Correlation between Keratoconus and Pollution. Ophthalmic Epidemiol 2021; 28:495-501. [PMID: 33502925 DOI: 10.1080/09286586.2021.1879173] [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: 10/22/2022]
Abstract
Introduction: Keratoconus is a corneal ectasia with multifactorial origin. Three risk factors for keratoconus are currently recognized: ultraviolet rays (UV), eye rubbing and atopy. In the current literature, other factors are evoked such as pollution, whose role in the physiopathology of keratoconus is unclear. The effects of particles matter (PM) 2.5 and 10 are the most studied and questioned in the scientific literature.Material and method: A correlation study was carried out to determine the influence of pollution on keratoconus. Fine particulate matter levels were measured according to available WHO data and were correlated with the prevalences of epidemiological studies. These measures were included in the study according to strict selection criteria.Results: The mean pollution rate of the selected studies was 29.1 ± 24.3 μg/m3 for PM2.5 and 57.2 ± 56.2 μg/m3 for PM10. The Pearson test shows a moderate correlation between the prevalence of keratoconus and the levels of PM2.5 (R = 0.51; p = .022) and a strong correlation with the levels of PM10 (R = 0.71; p < .001).Discussion: Fine particulate matter appears to be an emerging risk factor for keratoconus. They are thought to act indirectly by exacerbating known risk factors such as atopy and eye rubbing. And could have a direct action on the cornea by increasing the apoptosis of epithelial cells and interacting directly with the structure of collagen of the stroma.
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Affiliation(s)
- Tristan Jurkiewicz
- Pierre Wertheimer Hospital, Neuro-ophthalmology department, Bron, France.,Pierre Wertheimer Hospital, Bron, France
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Ferrari G, Rama P. The keratoconus enigma: A review with emphasis on pathogenesis. Ocul Surf 2020; 18:363-373. [PMID: 32234342 DOI: 10.1016/j.jtos.2020.03.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/11/2020] [Accepted: 03/19/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To review the literature on the etiopathogenesis of keratoconus (KC). METHODS A literature search was conducted using PUBMED and Google Scholar for keratoconus. The authors analyzed epidemiology studies, reviews, and case reports. RESULTS Atopy and ocular surface inflammation are a common features of KC and should lead to a reconsideration of the traditional definition of KC as a "non inflammatory" condition. Co-morbidities suggest that KC may be the ocular manifestation of a systemic disease. Finally, KC shows higher prevalence in certain ethnicities, which calls into question the status of KC as a rare disease, at least in these communities. CONCLUSION We believe that future studies should test whether selected, high prevalence populations exhibit specific genetic background and/or ethno-specific environmental risk factors.
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Affiliation(s)
- Giulio Ferrari
- San Raffaele Hospital, Cornea and Ocular Surface Unit, Eye Repair Lab, Italy.
| | - Paolo Rama
- San Raffaele Hospital, Cornea and Ocular Surface Unit, Eye Repair Lab, Italy
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Abstract
The scientific problem of epidemiology of keratoconus in different countries is covered in the article. The results of original studies were analyzed and a conclusion has been drawn that keratoconus is quite a common disease in the world.
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Affiliation(s)
- F I Abdulalieva
- National Centre of Ophthalmology named after acad. Zarifa Aliyeva, 32/15 Javadkhan St., Baku, Azerbaijan, AZ 1114
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Elbedewy HA, Wasfy TE, Soliman SS, Sabry MM, Awara AM, El Emam SY, Shafik HM, Alam MR. Prevalence and topographical characteristics of keratoconus in patients with refractive errors in the Egyptian delta. Int Ophthalmol 2018; 39:1459-1465. [DOI: 10.1007/s10792-018-0965-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/16/2018] [Indexed: 11/29/2022]
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Shanti Y, Beshtawi I, Zyoud SH, Abu-Samra A, Abu-Qamar A, Barakat R, Shehada R. Characteristics of keratoconic patients at two main eye centres in Palestine: a cross-sectional study. BMC Ophthalmol 2018; 18:95. [PMID: 29661163 PMCID: PMC5902985 DOI: 10.1186/s12886-018-0762-x] [Citation(s) in RCA: 6] [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: 05/22/2017] [Accepted: 04/03/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Keratoconus (KC) is a multifactorial, degenerative ectatic condition of the cornea. It usually manifests during late adolescence or the early twenties. A painless disease, KC may end with severe visual loss. The prevalence of KC in middle-eastern countries is much higher than in other regions of the world. This may be due to genetic and environmental risk factors and consanguinity. The goal of this study is to explore the demographic profile of Palestinian keratoconic patients. METHODS A retrospective study was conducted in two ophthalmology centres (Tertiary Ophthalmic Centre of An-Najah National University Hospital and An-Noor Centre at the Specialized Arab Hospital). All medical charts of keratoconic patients attending both centres over the period from 2009 to 2016 were reviewed. These patients were diagnosed by ophthalmologists depending on history, examination and Pentacam. Severity was determined using the k median index from the Pentacam map. Data analysis was carried out using SPSS Version 22. RESULTS The medical files of 936 keratoconic eyes of 505 keratoconic patients were reviewed. Their mean age at the time of diagnosis was 23.3 ranging from 8 to 62 years. Approximately 70.1% of them presented after the age of 20 years, and younger age groups were more likely to develop a severe disease stage than older ones (P = 0.001, r = - 0.108). There was a nearly equal distribution of patients between the two sexes (49.5% male, 50.5% female). On initial evaluation, the best-corrected visual acuity (BCVA) was recorded as ≥6/12 in most affected eyes (71.5%). Regarding severity, 62% presented in a mild form, while 9.9% were at a severe stage. About 88.2% presented with bilateralism. CONCLUSIONS Most of the patients in their twenties presented with a mild bilateral form of the disease. This result is compatible with published international reports. It is recommended that the results of this study be considered when establishing a screening program in Palestine. Subsequently, patients will be identified at an appropriate time where action can be taken before disease progression take place.
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Affiliation(s)
- Yousef Shanti
- 0000 0004 0631 5695grid.11942.3fPresent Address: Department of Ophthalmology, An-Najah National University Hospital, 44839 Nablus, Palestine Palestine
- 0000 0004 0631 5695grid.11942.3fDepartment of Medicine, College of Medicine and Health Sciences, An-Najah National University, 44839 Nablus, Palestine Palestine
| | - Ithar Beshtawi
- 0000 0004 0631 5695grid.11942.3fDepartment of Optometry, College of Medicine and Health Sciences, An-Najah National University, 44839 Nablus, Palestine Palestine
| | - Sa’ed H. Zyoud
- 0000 0004 0631 5695grid.11942.3fDepartment of Clinical and Community Pharmacy, College of Medicine and Health Sciences, An-Najah National University, 44839 Nablus, Palestine Palestine
| | - Ahlam Abu-Samra
- 0000 0004 0631 5695grid.11942.3fDepartment of Medicine, College of Medicine and Health Sciences, An-Najah National University, 44839 Nablus, Palestine Palestine
| | - Areen Abu-Qamar
- 0000 0004 0631 5695grid.11942.3fDepartment of Medicine, College of Medicine and Health Sciences, An-Najah National University, 44839 Nablus, Palestine Palestine
| | - Reem Barakat
- 0000 0004 0631 5695grid.11942.3fDepartment of Medicine, College of Medicine and Health Sciences, An-Najah National University, 44839 Nablus, Palestine Palestine
| | - Reham Shehada
- 0000 0004 0631 5695grid.11942.3fDepartment of Medicine, College of Medicine and Health Sciences, An-Najah National University, 44839 Nablus, Palestine Palestine
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Althomali TA, Al-Qurashi IM, Al-Thagafi SM, Mohammed A, Almalki M. Prevalence of keratoconus among patients seeking laser vision correction in Taif area of Saudi Arabia. Saudi J Ophthalmol 2017; 32:114-118. [PMID: 29942179 PMCID: PMC6010596 DOI: 10.1016/j.sjopt.2017.11.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 09/22/2017] [Accepted: 11/12/2017] [Indexed: 01/19/2023] Open
Abstract
Purpose To determine the prevalence of keratoconus among patients seeking laser vision correction (LVC). Methods Retrospective study of 1374 eyes of 687 patients (335 males, 352 females) who underwent keratoconus screening as a part of routine preoperative evaluation prior to LVC at the Tadawi surgical centre, Taif, Saudi Arabia from January 2014 to June 2015. The diagnosis of keratoconus was based on evaluation of Pentacam derived parameters. Results Manifest keratoconus was found in 59 subjects (out of 687 subjects) representing a prevalence rate of 8.59%. Of the 687 subjects, 45 subjects (6.55%) had bilateral manifest keratoconus (manifest keratoconus in both eyes or manifest keratoconus in one eyes and sub-clinical in contralateral eye) and remaining 14 patients (2.04%) had unilateral manifest keratoconus (with normal fellow eye). Sub-clinical keratoconus was diagnosed in 65 patients representing a prevalence rate of 9.46%. Of the 687 patients, 20 cases (2.91%) with subclinical keratoconus were bilateral and 45 (6.55%) were unilateral. Overall, 19.70% males (66/335) and 16.48% (58/352) females had either manifest or sub-clinical keratoconus, representing no statistically significant difference in the gender predisposition of the keratoconus disease process (Chi Square test; p = .277). Conclusion High prevalence of keratoconus was found among patients seeking LVC. Possible factors contributing to the high prevalence were recognized to be highly selective population (patients seeking LVC for myopia/hyperopia/astigmatism), ethnicity (high prevalence of consanguinity) and geographical location (high altitude) of the study subjects.
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Affiliation(s)
- Talal A Althomali
- Surgery Ophthalmology, Taif University, Taif, Saudi Arabia.,Tadawi Surgical Center, Taif, Saudi Arabia
| | | | | | | | - Mohammed Almalki
- Surgery Ophthalmology, King Abdullah Medical City, Makkah, Saudi Arabia
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Barbara R, Turnbull AMJ, Hossain P, Anderson DF, Barbara A. Epidemiology of Keratoconus. KERATOCONUS 2017. [DOI: 10.1007/978-3-319-43881-8_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Abstract
PURPOSE To evaluate the association between familial Mediterranean fever (FMF) and keratoconus (KC). METHODS This retrospective case-control study was performed to compare the prevalence of KC in patients with FMF with the corresponding prevalence in control patients without FMF referred to Genetic Diagnostic Center at Diskapi Yildirim Beyazit Training and Research Hospital from June 2012 to June 2015. We included all 100 patients with FMF. Each FMF-affected patient was matched to 3 controls. RESULTS None of the patients in the control group (0%, 0/300) had KC, whereas 4 of 100 patients with FMF (4%) had KC (P < 0.004). Three of 33 patients with a homozygous mutation (9.1%) (M694V/M694V in 2 cases and M680I/M680I in 1 case) and 1 of the 46 patients with a compound heterozygous mutation (2.2%) (M694V/M680I) had KC, whereas none of the 21 patients with a heterozygous mutation (0%) had KC. All patients with KC were women, and mean age was 40.8 years (range, 30-51). Although 1 of the 4 patients with KC had hypertension and type 2 diabetes mellitus, the other 3 patients did not have any systemic illness except FMF. When we compared the prevalence of KC in patients with FMF (4%) with the highest prevalence of KC reported in the literature (0.2%), FMF was a predisposing factor to develop KC [odds ratio: 18.1 (95% CI: 11.9-27.5)] especially in patients with a homozygous mutation [odds ratio: 43.4 (95% CI: 28.6-65.7)]. CONCLUSIONS Mediterranean fever (MEFV) gene mutations, particularly in homozygous mutations of the MEFV gene, may be a predisposing factor in the development of KC.
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The genetic and environmental factors for keratoconus. BIOMED RESEARCH INTERNATIONAL 2015; 2015:795738. [PMID: 26075261 PMCID: PMC4449900 DOI: 10.1155/2015/795738] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 12/22/2022]
Abstract
Keratoconus (KC) is the most common cornea ectatic disorder. It is characterized by a cone-shaped thin cornea leading to myopia, irregular astigmatism, and vision impairment. It affects all ethnic groups and both genders. Both environmental and genetic factors may contribute to its pathogenesis. This review is to summarize the current research development in KC epidemiology and genetic etiology. Environmental factors include but are not limited to eye rubbing, atopy, sun exposure, and geography. Genetic discoveries have been reviewed with evidence from family-based linkage analysis and fine mapping in linkage region, genome-wide association studies, and candidate genes analyses. A number of genes have been discovered at a relatively rapid pace. The detailed molecular mechanism underlying KC pathogenesis will significantly advance our understanding of KC and promote the development of potential therapies.
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Karamichos D, Hjortdal J. Keratoconus: tissue engineering and biomaterials. J Funct Biomater 2014; 5:111-34. [PMID: 25215423 PMCID: PMC4192608 DOI: 10.3390/jfb5030111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 08/26/2014] [Accepted: 09/03/2014] [Indexed: 12/20/2022] Open
Abstract
Keratoconus (KC) is a bilateral, asymmetric, corneal disorder that is characterized by progressive thinning, steepening, and potential scarring. The prevalence of KC is stated to be 1 in 2000 persons worldwide; however, numbers vary depending on size of the study and regions. KC appears more often in South Asian, Eastern Mediterranean, and North African populations. The cause remains unknown, although a variety of factors have been considered. Genetics, cellular, and mechanical changes have all been reported; however, most of these studies have proven inconclusive. Clearly, the major problem here, like with any other ocular disease, is quality of life and the threat of vision loss. While most KC cases progress until the third or fourth decade, it varies between individuals. Patients may experience periods of several months with significant changes followed by months or years of no change, followed by another period of rapid changes. Despite the major advancements, it is still uncertain how to treat KC at early stages and prevent vision impairment. There are currently limited tissue engineering techniques and/or "smart" biomaterials that can help arrest the progression of KC. This review will focus on current treatments and how biomaterials may hold promise for the future.
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Affiliation(s)
- Dimitrios Karamichos
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, DMEI PA-409, Oklahoma City, OK 73104, USA.
| | - Jesper Hjortdal
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C DK-800, Denmark.
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Hashemi H, Khabazkhoob M, Yazdani N, Ostadimoghaddam H, Norouzirad R, Amanzadeh K, Miraftab M, Derakhshan A, Yekta A. The prevalence of keratoconus in a young population in Mashhad, Iran. Ophthalmic Physiol Opt 2014; 34:519-27. [DOI: 10.1111/opo.12147] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 06/27/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Hassan Hashemi
- Noor Ophthalmology Research Center; Noor Eye Hospital; Tehran Iran
| | - Mehdi Khabazkhoob
- Department of Epidemiology; Faculty of Public Health; Shahid Beheshti University of Medical Sciences; Tehran Iran
| | - Negareh Yazdani
- Department of Optometry; School of Paramedical Sciences; Mashhad University of Medical Sciences; Mashhad Iran
| | - Hadi Ostadimoghaddam
- Department of Optometry; School of Paramedical Sciences; Mashhad University of Medical Sciences; Mashhad Iran
| | | | - Kazem Amanzadeh
- Noor Ophthalmology Research Center; Noor Eye Hospital; Tehran Iran
| | | | - Akbar Derakhshan
- Department of Ophthalmology; Mashhad University of Medical Sciences; Mashhad Iran
| | - AbbasAli Yekta
- Department of Optometry; School of Paramedical Sciences; Mashhad University of Medical Sciences; Mashhad Iran
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Shneor E, Millodot M, Blumberg S, Ortenberg I, Behrman S, Gordon-Shaag A. Characteristics of 244 patients with keratoconus seen in an optometric contact lens practice. Clin Exp Optom 2012; 96:219-24. [PMID: 23278637 DOI: 10.1111/cxo.12005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/07/2012] [Accepted: 08/21/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The purpose of this study was to describe the characteristics of keratoconic patients seen in a specialised contact lens practice from a general population with a high prevalence of the disease. METHODS Patients attending a contact lens practice for management of keratoconus were asked to complete a questionnaire. Data were collected on demographic characteristics, general health, family history, eye rubbing, allergy, asthma, eczema, education level, history of keratoplasty and smoking. RESULTS Two hundred and forty-four patients completed the questionnaire. There was a male bias (54.5 per cent). The majority of the patients (78.7 per cent) wore contact lenses, of whom 67.7 per cent wore hard, 13 per cent soft and 4.2 per cent scleral contact lenses. Some of the patients (21.3 per cent) had undergone corneal graft surgery. Eighteen per cent had an associated systemic disease, the most common of which was type 2 diabetes, although this disease was less prevalent, but not significantly, in the keratoconic sample than in the general population (p = 0.19). The prevalence of eye rubbing (65.6 per cent) was similar to other studies. Compared to the general population, asthma (13.2 per cent) was slightly, but not significantly, less prevalent (p = 0.17), eczema (6.6 per cent) was significantly less (p < 0.001) and allergy (34.4 per cent) was more prevalent (p < 0.001). A high proportion of patients reported a family history of the disease (27.9 per cent) and most were better educated than the general population. CONCLUSION The results of this survey concur with those of other studies with regard to most known characteristics of keratoconus; however, the proportion of asthma and eczema tended to be less than in other surveys and may be linked to the environmental influence of a hot and sunny country. The high prevalence of positive family history of the disease in this cohort suggests a genetic influence.
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Affiliation(s)
- Einat Shneor
- Department of Optometry, Hadassah Academic College, Jerusalem, Israel.
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Kozomara B, Bohač M, Potkonjak E, Kozomara I, Kozomara R, Gabrić N. Prevalence of keratoconus in candidates for refractive surgical procedures. SCRIPTA MEDICA 2012. [DOI: 10.5937/scriptamed1201025k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Abstract
ABSTRACT
Keratoconus is a noninflammatory disorder characterized by ectasia of the central or inferior portion of the cornea. This review presents the scant epidemiological information known to date and the factors believed to cause the development of the disease. They are the genetic factors for which evidence come from family studies, twin studies and genetic loci. There appears to be multiple genes causing a keratoconus phenotype with variable penetration. However, the genetic predisposition might not be enough; environmental factors, such as eye rubbing, atopy and UV exposure, may have a role in generating the disease.
How to cite this article
Gordon-Shaag A, Millodot M, Shneor E. The Epidemiology and Etiology of Keratoconus. Int J Keratoco Ectatic Corneal Dis 2012;1(1):7-15.
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