Flow chart for searching
Figure 1 shows the criteria for selecting publications for the collection, as follows: (1) a time interval of 2002 to 2021; (2) publication included in the WoSCC; (3) articles and reviews; (4) title and abstract available and related to the artificial cornea field.
Global trends of publications
Figure 2A shows the annual trends of publications and citations per publication about artificial cornea from 2002 to 2021. The period of papers published during the past 20 years could be divided into three periods: the initial period was from 2002 to 2007, with the growth rate being significantly low in this stage. The second stage was the development period from 2008 to 2014, with the growth rate remaining increased except from 2012 to 2013. And it showed a boom period from 2015 to 2021, accounting for 49.8% (426) of all publications. The most published year was 2016, with 70 publications. The number of published articles presented a stable pattern.
In total, 829 articles published in the past 20 years were included through our search strategy. Over 99% of these articles were published in English. Most of the publications were original research articles (732, 88.3%), and review articles accounted for 11.7% with 97 publications.
Countries and institute distribution
The articles we collected were from 64 different countries/regions (Figure 2B). We ranked the top 10 most highly outputs countries/regions in Table 1. The USA had the most articles published (381, 46.0%), followed by China (84, 10.1%) and Canada (80, 9.7%). Figure 2A reveals the annual trends of publications of the five most high-cited countries/regions. Total citations of all the countries/regions were 17,812 times. Articles from the USA were cited by 8387 times, accounting for 47.1% of all the citations, followed by Canada (1768, 9.9%) and China (1339, 7.5%) (Figure 3B). Among the collaboration between countries/regions (Figure 2C) and the percentage of multiple country publications (Figure 3A), we found many countries actively cooperating with other countries, including the USA, Canada and the UK. The most cooperation was between the USA and Canada. Researchers from China, Japan and India were lower active in collaboration with other countries. Figure 2D shows a country/region co-authorship produced by VOSviewer. Out of the 25 countries/regions with at least 8 articles used to generate the co-authorship network, the USA was the most influential country/region with a total link strength (TLS) is 189, followed by the UK (TLS=61) and Brazil (TLS=45).
Table 1
The top 10 most prolific countries/regions in publishing documents on artificial cornea.
Ranking
|
Country/Region
|
TP (%)
|
SCP (%)
|
MCP (%)
|
1
|
USA
|
340
|
243(71.5)
|
97(28.5)
|
2
|
China
|
79
|
68(86.1)
|
11(13.9)
|
3
|
Canada
|
61
|
49(80.3)
|
12(19.7)
|
4
|
India
|
42
|
38(90.5)
|
4(9.5)
|
5
|
Germany
|
40
|
32(80.0)
|
8(20.0)
|
6
|
UK
|
39
|
21(53.9)
|
18(46.1)
|
7
|
Spain
|
31
|
18(58.1)
|
13(41.9)
|
8
|
Singapore
|
26
|
19(73.1)
|
7(26.9)
|
9
|
Australia
|
25
|
9(36.0)
|
16(64.0)
|
10
|
Japan
|
24
|
22(91.7)
|
2(8.3)
|
TP, number of total articles; SCP, Number of publications with intra-country collaboration; MCP, Number of publications with inter-country collaboration.
In our study, 890 institutions contributed to the publications we included. The 69 institutions with a minimum of 5 documents were demonstrated in Figure 3C. Harvard University in the USA holds the most publications, followed by University of Illinois in the USA and L V Prasad Eye Institute in India. We ranked in the top 10 most prolific institutions in this research field in Table 2. Seven institutions are from the USA, two in Singapore, and the other in India. From Figure 3D, the most prolific institutions published main articles from 2012 to 2016. Figure 4B shows the institution collaboration network, the most collaborative organization is Singapore National Eye Center, followed by Singapore Eye Research Institution and Harvard University.
Table 2
The top 10 productive institutions.
Ranking
|
Institution
|
Articles
|
TC
|
CPP2021
|
Country
|
1
|
Harvard Univ
|
166
|
1902
|
11.5
|
USA
|
2
|
Univ Illinois
|
48
|
355
|
7.4
|
USA
|
3
|
LV Prasad Eye Inst
|
42
|
233
|
5.6
|
India
|
4
|
Univ Calif Los Angeles
|
36
|
668
|
18.6
|
USA
|
5
|
Singapore Natl Eye Ctr
|
32
|
471
|
14.7
|
Singapore
|
6
|
Johns Hopkins Univ
|
31
|
359
|
11.6
|
USA
|
7
|
Stanford Univ
|
31
|
284
|
9.2
|
USA
|
8
|
Singapore Eye Res Inst
|
31
|
231
|
7.5
|
Singapore
|
9
|
Massachusetts Eye & Ear Infirm
|
29
|
614
|
21.2
|
USA
|
10
|
Sankara Nethralaya
|
29
|
224
|
7.7
|
India
|
TC: number of citations. CPP: number of citations per publication.
Journals and articles distribution
All the publications were from 189 different journals in the past 20 years. We have comprehensively ranked the features of the 10 most prolific journals collectively in Table 3. The journals published 378 articles, accounting for 45.6% of all the publications. Cornea was the most productive journal of all (164, 19.8%). This was followed by the American Journal of Ophthalmology (37, 4.5%) and the British Journal of Ophthalmology (36, 4.3%). All these journals were categorized into ophthalmology apart from the Biomaterials. Articles from Cornea were the most cited, with citations 3554 times, followed by Ophthalmology (1848) and American Journal of Ophthalmology (966). Ophthalmology ranked first in the number of citations per publication (61.6), followed by Biomaterials (54.1). The dual-map overlay of journals in Figure 4C was performed by CiteSpace. The citing journal graphs are in the left cluster, while the cited journal graphs are in the right. The lines on the left and right are citation links [25]. We found that most articles were published in journals of neurology, sports and ophthalmology, and these journals mainly cited journals of chemistry/materials/physics, molecular/biology/genetics and ophthalmology.
The first 10 most cited articles are listed in Table 4. The citations of the paper written by Zebra BL in 2006 were 260 times, ranking the first. Of all the 10 articles, only one was a review article, as the others were all research articles. Eight of the articles were written by American scholars while the other authors were from Canada and China, respectively. Most of the articles were published in ophthalmologic journals with articles published in materials journals.
Table 3
The top 10 most prolific journals.
Ranking
|
Journal
|
Counts (%)
|
TC
|
h-index
|
IF2021
|
Web of Science category
|
CPP2021
|
1
|
Cornea
|
164 (19.8)
|
3554
|
32
|
3.152
|
Ophthalmology
|
21.7
|
2
|
American Journal of Ophthalmology
|
37 (4.5)
|
966
|
18
|
5.488
|
Ophthalmology
|
26.1
|
3
|
British Journal of Ophthalmology
|
36 (4.3)
|
564
|
14
|
5.908
|
Ophthalmology
|
15.7
|
4
|
Ophthalmology
|
30 (3.6)
|
1848
|
22
|
14.277
|
Ophthalmology
|
61.6
|
5
|
Ocular Surface
|
23 (2.8)
|
484
|
16
|
6.268
|
Ophthalmology
|
21.0
|
6
|
Investigative Ophthalmology & Visual Science
|
23 (2.8)
|
589
|
12
|
4.925
|
Ophthalmology
|
25.6
|
7
|
Graefes Archive for Clinical and Experimental Ophthalmology
|
19 (2.3)
|
354
|
12
|
3.535
|
Ophthalmology
|
18.6
|
8
|
Retina-The Journal of Retinal and Vitreous Disease
|
17 (2.1)
|
171
|
8
|
3.975
|
Ophthalmology
|
10.1
|
9
|
Current Opinion in Ophthalmology
|
15 (1.8)
|
449
|
11
|
4.299
|
Ophthalmology
|
29.9
|
10
|
Biomaterials
|
14 (1.7)
|
758
|
13
|
15.304
|
Engineering, biomedical
|
54.1
|
TP: number of articles; %, the percentage of articles in total publications; IF: journal impact factor; CPP, number of citations (TC) per publication (TP).
Table 4
Top 10 most cited articles in artificial cornea field.
First author
|
Title
|
Year
|
Journal
|
Quartile in category
|
IF
|
TC
|
Type
|
Countries /Regions
|
Zerbe BL
|
Results from the multicenter Boston Type 1 Keratoprosthesis Study
|
2006
|
Ophthalmology
|
Q1
|
14.277
|
260
|
Research article
|
USA
|
Aldave AJ
|
The Boston type I keratoprosthesis: improving outcomes and expanding indications
|
2009
|
Ophthalmology
|
Q1
|
14.277
|
222
|
Research article
|
USA
|
Duan X
|
Dendrimer crosslinked collagen as a corneal tissue engineering scaffold: Mechanical properties and corneal epithelial cell interactions
|
2006
|
Biomaterials
|
Q1
|
15.304
|
220
|
Research article
|
Canada
|
Chew HF
|
Boston keratoprosthesis outcomes and complications
|
2009
|
Cornea
|
Q2
|
3.152
|
182
|
Research article
|
USA
|
Wang JH
|
Preparation and in vitro characterization of BC/PVA hydrogel composite for its potential use as artificial cornea biomaterial
|
2010
|
Mat Sci Eng C-Mater
|
Q2
|
7.328
|
151
|
Research article
|
China
|
Ruberti JW
|
Corneal biomechanics and biomaterials
|
2011
|
Annu Rev Biomed Eng
|
Q1
|
11.324
|
141
|
Review
|
USA
|
Greiner MA
|
Longer-term vision outcomes and complications with the Boston type 1 keratoprosthesis at the University of California, Davis
|
2011
|
Ophthalmology
|
Q1
|
14.277
|
138
|
Research article
|
USA
|
Bradley JC
|
Boston type 1 keratoprosthesis: the university of california davis experience
|
2009
|
Cornea
|
Q2
|
3.152
|
135
|
Research article
|
USA
|
Falcinelli G
|
Modified osteo-odonto-keratoprosthesis for treatment of corneal blindness: long-term anatomical and functional outcomes in 181 cases
|
2005
|
Arch Ophthalmol-Chic
|
Q1
|
8.253
|
134
|
Research article
|
Italy
|
Sayegh RR
|
The Boston keratoprosthesis in Stevens-Johnson syndrome
|
2008
|
Am J Ophthalmol
|
Q1
|
5.488
|
121
|
Research article
|
USA
|
IF, impact factor. TC. total citations.
Authors and co-authors distribution
Over 2,900 authors made contributions to the publications included in our study. We identified the 10 most productive authors in the artificial cornea area including h-index, citations, countries and publications (Table 5). Scientists from the USA contribute an enormous of articles to this field. Dohlman CH was the most active author, with 70 articles, followed by Chodosh J(57) and Harissa-Dagher M(42). In terms of citations in this area, the first author was the same as the most productive. Dohlman CH ranked first with 1206 times and followed by Aldave AJ(608) and Harissa-Dagher M, with 529 times. The collaborations between authors are presented in Figure 4B. the 5 authors with the highest TLS were Dohlman CH (TLS=3344), Chodosh J (TLS=2535), Harissi-Dagher M (TLS=1890), Aldave AJ (TLS=1581) and Yu F (TLS=1050).
Table 5
The top 10 productive authors.
Ranking
|
Author
|
TP
|
TC
|
TLS
|
h-index
|
Country
|
1
|
Dohlman CH
|
70
|
1924
|
3344
|
27
|
USA
|
2
|
Chodosh J
|
57
|
1045
|
2535
|
21
|
USA
|
3
|
Harissi-Dagher M
|
42
|
851
|
1890
|
18
|
Canada
|
4
|
Akpek EK
|
25
|
706
|
1581
|
16
|
USA
|
5
|
Aldave AJ
|
24
|
865
|
726
|
15
|
USA
|
6
|
Aquavella JV
|
16
|
645
|
764
|
14
|
USA
|
7
|
Mehta JS
|
19
|
461
|
753
|
13
|
Singapore
|
8
|
Robert MC
|
20
|
418
|
880
|
13
|
Canada
|
9
|
Cortina MS
|
27
|
397
|
1032
|
12
|
USA
|
10
|
De La Cruz J
|
21
|
386
|
584
|
12
|
USA
|
TP: number of articles; TC: number of citations; TLS: total link strength.
Analysis of keywords
The core word extractions provided by scholars in the studies are keywords. According to the treemap of the most frequent 20 author keywords (Figure 5A), the top five keywords with a significant number of occurrences are outcomes that appear 147 times; complications 117 times; implantation 89 times; penetrating keratoplasty 88 times and surgery 85 times. The burst keywords through CiteSpace were explored and 20 keywords with the strongest strength of the last 20 years were identified (Figure 5B). We used CiteSpace to perform subject clustering map (Figure 5D) and timeline (Figure 5C). The articles on the artificial cornea field published from 2002 to 2021 could be categorized into 10 main research hotspots, each of different sizes and periods. The modularity Q value was 0.7394 and the average silhouette value was 0.8919, demonstrating that clustering quality was acceptable. The first 10 clusters were generalized and ordered from the largest to the smallest number of co-cited references. The first cluster was “#0 long-term outcome”, and this was followed by “#1 corneal epithelial cell migration” and “#2 anterior segment”. The top 20 keywords with the most vigorous citation burst are shown in Figure 4B. The earliest and highest strength burst keyword in the past 20 years was “artificial cornea”, which was from 2002 to 2010. The keywords appeared at different time points and periods, with the highest intensity of the words was “retention” in recent years. As shown in the timeline view, a cluster called “#2 anterior segment” appeared in recent years. The cluster “#0 long-term outcome”, “#5 Boston keratoprosthesis type” and “#7 corneal regeneration” were present throughout.