Top 100 cited articles in ophthalmic epidemiology between 2006 and 2016

Lei Liu1,2,3, Yan Li4, Gui-Sen Zhang5, Jing-Yang Wu1, Shivani Majithia3, Yih-Chung Tham3, Han Zhang1,Lei Chen1,6

1Department of Ophthalmology, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China

2Department of Public Service, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China

3Singapore Eye Research Institute, Singapore National Eye Centre, 168751, Singapore

4Department of English, School of Fundamental Sciences,China Medical University, Shenyang 110122, Liaoning Province, China

5Department of Ophthalmology, Hohhot Chao Ju Eye Hospital,Hohhot 010052, Inner Mongolia Autonomous Region, China

Abstract● AlM: To identify the most-cited articles in ophthalmic epidemiology over the last decade.● METHODS: We performed a cited reference search on articles that were included in the lSl Web of Science database using the terms “Epidemi＊” AND “ophthalm＊”AND “population＊” during year 2006 to 2016. TOP 100 most cited articles (T100) in ophthalmic epidemiology were short listed and analysed using bibliometrics.● RESULTS: These top 100 articles in ophthalmic epidemiology were cited between 61 to 333 times. Of these T100 articles,36% originated from United States, and 34% were published in theOphthalmologyjournal. The three major topics identified were age-related macular degeneration (AMD,n=23), glaucoma (n=16) and visual impairment (n=12). The top-cited article was a study on outdoor activities and its association with the prevalence of myopia in school-aged children, published in 2008.● CONCLUSlON: This bibliometric analysis provides useful insights into the current development in ophthalmic epidemiology in the past decade and can help recognizing the quality of the researches, discoveries, and trends steering ophthalmic epidemiology.

INTRODUCTION

Bibliometric study is the quantitative analysis of written publications such as journal articles using statistical and mathematical methods[1-2]. This approach is useful in evaluating trends in research over time. Currently, bibliometric analysis is widely used in the determination and evaluation of in fluential literature[3-4]. Bibliometric study also helps to identify the frequency of citations and thus the impact of scienti fic articles post-publication[5-6]. Reviewing the most frequently cited articles help researchers to identify areas in certain specialties that may require further investigation.

In the area of ophthalmology, ophthalmic epidemiology has seen significant advancement for the past ten years.Ophthalmic epidemiology study usually involves collaboration of multidisciplinary groups of researchers, including those from the areas of ophthalmology, epidemiology, statistics and public health. Thus, the ophthalmic epidemiology bibliometric analysis encompasses publications from numerous study groups varying among specialties and countries of origin,and appearing in a range of scientific journals. Furthermore,these advances in ophthalmic epidemiology are important as they provide useful information on the trends of eye diseases and have great impact on the promotion of eye and vision health[7-9]. In addition, the most in fluential articles and the focus of study fields can be evaluated by analyzing the most highly cited articles. In 2008, a literature review and interpretation on population-based studies in ophthalmology has been applied to summarize key questions, and to highlight future insights for this area[10]. However, similar review or bibliometric analysis has not yet been performed in the area of ophthalmic epidemiology since 2008. Hence, the purpose of this workwas to reviewed the characteristics of the top 100 most cited articles (T100) in ophthalmic epidemiology in the past decade,from 2006-2016. These findings will provide new insights on the research trends in ophthalmic epidemiology.

MATERIALS AND METHODS

Search StrategyFrom the Journal Citation Reports 2017 database, we identified 59 ophthalmology-related journals.ISI Web of Science (Institute for Scientific Information,Thomson Scienti fic, Philadelphia, Pennsylvania) database was further used to determine the number of citations of articles published in the identified 59 journals (Table 1) and 4 top general medicine journals includingJournal of The American Medical Association (JAMA),The New England Journal of Medicine (NEMJ),The LANCETandThe British Medical Journal (BMJ). The retrieved articles were strictly limited to studies in the field of ophthalmic epidemiology, searched and filtered using the terms [Epidemi* AND ophthalm* AND population*]. All abstracts for studies discovered during the search process were thoroughly reviewed and evaluated before being included in the study.

Inclusion and Exclusion CriteriaThe inclusion criteria for articles were as follow: 1) epidemiological studies on eye diseases; 2) population-based study design; 3) cross-sectional or cohort study design; 4) written in English; 5) published between January 2006 and December 2016. We excluded articles for the following reasons: 1) conference abstracts,reviews, letters, and editorials; 2) Meta-analysis; 3) published in languages other than English.

The search was performed by two researchers (Liu L and Wu JY) independently in July 2017. The inconsistent outcomes were resolved by discussion within all the authors. The T100 were selected based on the following parameters: title, journal,citation frequency, authorship, institution, country of origin,and categories of research topics [e.g.age-related macular degeneration (AMD), diabetic retinopathy (DR), myopia, and visual impairment]. All contributing authors of the articles were included in the search to find the most-published, and not just the corresponding author for each paper.

Statistical AnalysisAll outcomes were exported into Microsoft Excel spreadsheets. We used a median and interquartile range (IQR) to present the average citation number. If more than two articles were cited by the same frequency, they would be provided the same ranking in the list.

RESULTS

Citation Count, Citations per Year and Publication YearThe total number of citations of the T100 ranged from 61 to 333, with a median of 99.5 (IQR: 81-146.25). Approximately 6%of the total citation count was from self-citations. The number of citations per year ranged from 6.1 to 33.3. The median number of citations per year was 10.46 (IQR: 8.21-15.24).

Table 2 demonstrates the T100 in ophthalmic epidemiology,categorised by publication year. Year 2008 recorded the highest number of citations (3832) from 31 articles.

Journals, Origins, Institution and AuthorshipThe T100 in ophthalmic epidemiology were published in 11 different journals (Table 3). Among which, wereOphthalmology,Archives of Ophthalmology,Investigative Ophthalmology Visual Science, andAmerican Journal of Ophthalmologywere the top 4 journals which published 12 or more of these articles each. In addition, there were 2 articles fromJAMAand 1 article fromThe Lancet, respectively. The latest impact factors of these 11 journals ranged from 1.758 to 47.831 (based on 2016 Journal Citation Reports, Thomson Reuters).

The region of origins of the T100 were shown in Table 4. The T100 were produced from 17 regions. Of which, 36 articles were from USA, with total citation numbers of 4654. There were 18 articles (2443 citations) from Singapore and 16 articles (1765 citations) from China. Notably, there were 2 articles from Kenya and Nigeria regarding visual impairment which gained 76 and 63 citations, respectively.

Distribution by Topic TypeTable 5 showed the main research topics published among the T100. In total, 17 fields were covered. Notably, AMD was the most common topic(n=23), followed by glaucoma (n=16), visual impairment(n=12), myopia (n=9), and DR (n=9).

DISCUSSION

In this current bibliometric analysis, we screened 59 ophthalmology-related journals to determine the T100 in field of ophthalmic epidemiology using the ISI Web of Science, for publication year 2006 to 2016. The T100 were published in 11 journals, most were published inOphthalmology(n=34),followed byArchives of Ophthalmology(current known asJAMA Ophthalmology,n=21) andInvestigative Ophthalmology Visual Science(n=19). These three journals are associated with the subject category of ophthalmic epidemiology, which in many ways is the cornerstone of population-based eye study. In addition, the T100 were produced by 17 differentcountries, most were originated from the United States (n=34).These findings provide insights and trends in ophthalmic epidemiology research that could serve as useful references or future research directions. The most frequently cited article in the field of ophthalmic epidemiology was published inOphthalmologyby Rose KA and colleagues in 2008 into the topic of myopia, highlighting that higher levels of total time spent outdoors were associated with less myopia and a more hyperopic mean refraction. In general, our bibliometric findings provide a comprehensive review of landmark articles published in the field of ophthalmic epidemiology; these top cited articles reflect major advances and hot topics over the past decade.

To the best of our knowledge, this is the first bibliometric work on the T100 published in the last ten-year in field of ophthalmic epidemiology study. Bibliometric study provides the quantity and quality of outcomes within a given field,topic, author or location. As a part of bibliometric study,citation analysis is based on the premise that top-cited articles are frequently recommended by experts, this in turn helps to demonstrate emerging topics within each specialty field[11].Additionally, they help to provide a substantial indication of trends in that field[12-18].

The highest number of articles in the T100 was published inOphthalmology. These articles had the highest impact factor(8.024 in 2016), which may also account for their increased citation frequency. In addition,Archives of Ophthalmologychanged its name toJAMA Ophthalmology[19]in 2013, which is a medical journal under the American Medical Association.This change in journal name may have impacted the citation frequency of articles published inJAMA Ophthalmology(formerly known asArchives of Ophthalmology) as the name change may have caused confusion among some readers.

The majority of most-cited ophthalmic epidemiology studies focused on AMD. The top-ranked article in the field of AMD was from the Beaver Damn Eye Study where the authors investigated the long-term incident signs of AMD[20]. The topranked article in the field of glaucoma was a study researching the association between myopia and glaucomatous optic nerve damage[21]. In the field of visual impairment, the top-ranked article was on the causes of blindness and visual impairment in Beijing Eye Study[22]. Interestingly, we found that among the three major fields of the T100, the top-ranked articles were published inOphthalmology. In addition,Ophthalmologyhas higher impact factor score compared to other ophthalmic journals.

While the current analysis has supplied useful information on the research trends in ophthalmic epidemiology, there are some limitations to our study. Firstly, our search was limited to articles published over the last ten years. Second, we also did not include systemic review and Meta-analysis type of publications for this work. Third, older articles may have a greater chance of being cited due to increased exposure time compared to recent ones. Lastly, there may be bias in our literature search as the only search engine used was Web of Science and only English language publications were analysed.In summary, this study shows that the popular topics in ophthalmic epidemiology for the past decade are AMD,glaucoma and visual impairment.Ophthalmologywas the mist highly cited journal. This bibliometric analysis of the T100 in ophthalmic epidemiology provided insights into the current development in this field.

ACKNOWLEDGEMENTS

We sincerely thank Mrs. Heither Hope from the SUNBO foreign language school for language editing.

Foundations:Supported by National Natural Science Foundation of China (No.81300783); Scientific Research Project of Liaoning Provincial Department of Education (No.LQNK201703).

Conflicts of Interest: Liu L,None;Li Y,None;Zhang GS,None;Wu JY,None;Majithia S,None;Tham YC,None;Zhang H,None; Chen L,None.

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Citation:Liu L, Li Y, Zhang GS, Wu JY, Majithia S, Tham YC,Zhang H, Chen L. Top 100 cited articles in ophthalmic epidemiology between 2006 and 2016.Int J Ophthalmol2018;11(12):1994-1998

● KEYWORDS:epidemiology; ophthalmology; article;citation; bibliometric analysis

Correspondence to:Lei Liu. Department of Ophthalmology,First Af filiated Hospital of China Medical University, No.155 Nanjing North Street, Shenyang 110001, Liaoning Province,China. liuleijiao@163.com