Content uploaded by Rahmi Duman
Author content
All content in this area was uploaded by Rahmi Duman on Mar 10, 2016
Content may be subject to copyright.
The European Research Journal
http://www.eurj.org
Original
Article
e-ISSN: 2149-3189 DOI: 10.18621/eurj.2016.2.1.30
Analysis of the cornea donor data: an eye bank study
Ayse Balikci Tufekci1, Sadik Gorkem Cevik1, Neslihan Parmak1, Rahmi Duman2, Mediha Tok Cevik3,
Burcu Kazanci4, Mehmet Emin Aslanci1, Ersin Yucel1
1Department of Ophthalmology, Bursa Yuksek Ihtisas Training and Research Hospital, Bursa, Turkey
2Department of Ophthalmology, Afyon Kocatepe University Medical School, Afyon, Turkey
3Department of Ophthalmology, Düzici State Hospital, Osmaniye, Turkey
4Department of Ophthalmology, Ankara Ulucanlar Training and Research Hospital, Ankara, Turkey
ABSTRACT
Objectives. To analyse 1.5-year data of our newly established eye bank and to evaluate the factors affecting
donor quality. Methods. Our bank’s donor cornea data between July 2013 and November 2014 were retrospec-
tively analysed. The effects of donor age, sex, and time from death to harvesting on the findings of specular
microscopy were assessed. Results. A total of 139 corneas retrieved from 70 donors. The mean age of donors
was 34.2±14.6 (5-64) years. The mean time from death to harvesting was 6.7±2.9 (1-13) hours; the mean time
from collection to transplantation was 5.2±2.8 (1-14) days. Age had a significant negative correlation with
mean endothelial cell count (ECC), a significant positive correlation between mean cell area (MCA) and stan-
dard deviation (SD). Time from death to harvesting had a significant negative correlation with cell count and
6A; it had a significant positive correlation with SD, the coefficient of variation, and MCA. Conclusion. Ac-
cording to the results of the present study, ECC, MCA, and SD levels were greater in younger donors. En-
dothelial morphology was altered as the time from death to harvesting was prolonged; however, the alteration
in cell morphology was not severe enough to alter transplantation success with the corneas being harvested
within the first 13 hours.
Eur Res J 2016;2(1):30-35
Keywords: Eye Bank; cornea; specular microscopy; endothelial; donor
Introduction
Eye banks are special medical units responsible for
harvesting donor corneal tissue required for the cornea
transplantation from suitable donors, preserving
harvested tissues under appropriate conditions,
evaluating tissue quality for transplantation,
transporting tissues to transplant centres under optimal
conditions, registering patients who apply for
keratoplasty procedure, as well as establishing and
maintaining communication with the
patients. Donor suitability, time from donor death to
tissue harvesting, cornea storage conditions, and time
of harvesting to transplantation are vital factors for
graft survival during the time of harvesting to
transplanting corneal tissue. Corneal storage duration
is dependent on corneal preservation methods (tissue
culture medium, organ culture, moist chamber);
corneal tissue should be transplanted as soon as
possible before irreversible degeneration occurs after
Address for correspondence:
Sadik Gorkem Cevik, Department of Ophthalmology, Bursa Yuksek Ihtisas Training and Research Hospital, Bursa, Turkey
Email: gorkemcevik@hotmail.com
Received: 04.08.2015; Accepted: 10.09.2015; Published Online: 04.03.2016
Copyright © 2016 by The Association of Health Research & Strategy
30
donor death and during storage [1].
As a result of continuously increasing the number
of patients entering keratoplasty waiting lists and
prolonged waiting durations, Turkish Ministry of
Health has recently funded the establishment of new
eye banks in various cities. As of the time of the
writing this paper, there are 28 functioning eye banks
in Turkey. Our eye bank was established in July 2013
by ministerial approval of Turkish Ministry of Health
and supplied 139 donor corneal tissues between July
2013 and November 2014. In the following we want
to assess the first donor data of our newly established
eye bank.
Methods
Data of donor corneas harvested at Bursa Yuksek
Ihtisas Training and Research Hospital Eye Bank
between July 2013 and November 2014 were
retrospectively reviewed. Data on donor age, sex, time
of death to harvesting, time from collection to
transplantation, serology results, specular microscopy
(SM) results, and donor usage were recorded. In
specular microscopy, the Centre Method was used to
determine the corneal endothelial count and
endothelial structure (polymegathism and
pleomorphism) (Konan Eye Bank Kerato Analyzer,
Konan Medical Inc., Japan). The effects of donor age,
sex, and time from death to cornea harvesting on the
findings of specular microscopy were analysed. The
local ethics committee approved the study. After being
harvested from the cadavers using the sclerocorneal
button technique, donor corneas were preserved in the
preservation solution (Eusol C, Alchimia, Italy) at
4°C; and endothelial photographs were taken to be
examined for four times from all corneas by the same
person using specular microscopy. For each donor
cornea, endothelial cell count (ECC), mean cellular
area (MCA), standard deviation (SD), hexagonality
ratio (6A), and coefficient of variance (CV) were
recorded. The donors were categorized into four age
groups. Donor gender distribution, corneal side
distribution, endothelial count, SD, CV, 6A, MCC,
time from death to harvesting and time from collection
to transplantation were compared across the four age
groups.
Statistical analysis
Descriptive statistics included mean, standard
deviation, median, minimum, maximum, frequency,
and percentage. The distribution of study data was
tested with the Kolmogorov-Smirnov test.
Quantitative data were analysed with ANOVA and
Kruskal-Wallis (Mann-Whitney U) tests. Chi-Square
test was used for the analysis of qualitative data. SPSS
22.0 software package was used for all statistical
comparisons.
Results
Among 70 donors included in the study, 16 (23%)
were female, and 54 (77%) were male. During our
study period, 139 corneal tissues were retrieved from
70 donors. A pair of corneas was harvested from 69
donors and a single cornea from 1 donor. The mean
age of the donors was 34.2±14.6 (5-64) years. The
mean time from death to harvesting was 6.7±2.9 (1-
13) hours; the mean time from collection to
transplantation at different centres was 5.2±2.8 (1-14)
days. The mean age of the transplant recipients was
45.8±25 (1-88) years at various centres. The obtained
corneas were serologically tested using anti-HIV,
HBsAg, anti-HCV and VDRL tests. Two corneas were
HBsAg positive and were thus disposed of.
Another cornea was disposed of by a recipient
centre due to suspected infection. The findings of
specular microscopy, age and sex group distribution
of corneal tissues were shown in Table 1.
There were no significant differences between the
age groups on gender distribution and the distribution
of corneal tissue side. The cell count was significantly
greater in the first age group (5-19 years) compared
with the second (20-34 years), third (35-49 years), and
fourth (50-65 years) age groups (p<0.001). The cell
count was significantly greater in the second age group
compared to the 3rd and 4th age groups (p<0.001)
(Table 2). The SD level was significantly lower in the
first age group compared to the second, third, and
fourth age groups (p<0.001). It was also significantly
lower in the second age group compared to the fourth
age group (p<0.001) (Table 2). There were no
significant differences between the age groups on CV,
6A, time from death to harvesting, and time from
collection to transplantation (Table 2). The first age
group had a significantly lower MCA compared to the
second, third, and fourth age groups (p<0.001) The
MCA level was significantly lower in the second age
group compared to the 3rd and 4th age groups (p<0.001)
Eur Res J 2016;2(1):30-35 Cornea donor data
31
( Table 2).
Cell count, SD, CV, 6A, and MCA levels were not
significantly different between both genders (Table1).
Time from death to harvesting had a significant
negative correlation between cell count and 6A
(p=0.005). It had a significant positive correlation with
SD, CV (p<0.001 for both), and MCA (p=0.011)
(Table 3). Twenty-nine (21%) of the harvested corneas
were used at our hospital while the remaining 108
(79%) corneas were sent to other requesting
institutions. Two corneas had HBsAg positivity and
were thus disposed of.
Discussion
Today, there is an estimated 4.9 million patients
with bilateral corneal blindness worldwide, especially
in the developing countries, who may potentially
regain their visual ability with corneal transplantation.
According to the World Health Organisation data,
120.000 keratoplasties (KP) operations were
performed in 2000 worldwide [2, 3]. According to the
data of the Turkish Ministry of Health, the numbers of
keratoplasty operations were 1784 and 1921 in 2012
and 2013, respectively. The official number of patients
who are in the cornea waiting lists is 4822, although
unofficial estimates put the number at 10.000 [5, 6].
Evaluation of donor candidacy according to
certain standards is vital to operational success and
preventing complications. For this purpose, the
European Eye Bank Association (EEBA) and the Eye
Bank Association of America (EBAA) have set up the
minimum medical standards for donor candidacy [7,
8]. FDA undertakes supervision and certification of
the eye banks in the United States. The available
standards are reviewed twice a year, published by the
American Academy of Ophthalmology, and
!!!!!!
Table 2. Age groups with the distribution of specular microscopy findings.
Age groups
5-19 Years
20-34 Years
35-49 Years
50-65 Years
p
Cell Count
3319 ± 361
2947 ± 358*
2685 ± 366*#
2518 ± 326*#
<0.001
SD
95.2 ± 42.6
113.7 ± 31.7*
114.9 ± 26.9*
133.0 ± 35.5*#
<0.001
CV
30.3 ± 8.9
32.7 ± 6.4
30.3 ± 5.0
32.6 ± 5.8
0.051
6A
63.9 ± 10.0
59.2 ± 6.9
59.9 ± 8.2
61.5 ± 8.5
0.111
MCA
304.8 ± 38.5
343.2 ± 41.5*
377.7 ± 52.9*#
403.8 ± 53.8*#
<0.001
Harvesting time (h)
6.1 ± 2.7
6.7 ± 3.2
6.7 ± 2.8
7.3 + 3.0
0.504
Transplantation time (h)
4.7 ± 3.1
5.7 ± 3.2
4.8 ± 2.5
5.7 ±2.4
0.212
Recipient Age
32.6 ± 25.6
42.6 ± 23.9*
55.4 ± 21.1*#
52.1 ± 20.7*
0.001
SD= Standart deviation, CV=coefficient of variance, 6A=hexagonality ratio, MCA=mean cellular area,
Kruskal-Wallis / ANOVA, * p< 0.05 vs. 5-19 years age group / # p< 0.05 vs. 20-34 years age group
!
!
!
!
!
!!
Eur Res J 2016;2(1):30-35 Tufekci et al
!!!!!!
Table 1. Specular microscopy, age and sex group distribution of corneal tissues
Min-Max
Median
Mean ± SD
Donor Age
5–64
34
34.2 ± 14.6
Age Groups
5-19
34 (24.5%)
20-34
37 (26.6%)
35-49
43 (30.9%)
50-65
25 (18.0%)
Cell Count
2008 – 3968
2857
2884.0 ± 457.3
SD
53.0 – 257.0
106.0
112.7 ± 36.2
CV
19.0 – 60.0
30.0
31.4 ± 6.7
6A
39.0 – 81.0
61.0
61.1 ± 8.6
MCA
252.0 – 498.0
347.0
354.3 ± 58.4
SD= Standart deviation, CV=coefficient of variance, 6A=hexagonality ratio, MCA=mean cellular area
32
distributed to eye banks that are members of EBAA
[9].
A donor cornea having appropriate criteria for
transplantation is one of the most important factors
determining the keratoplasty success. Therefore, a
harvested cornea should undergo a specular
microscopic and serological evaluation before
keratoplasty. Some studies using specular microscopy
have shown that race, sex, and age of a person may
alter morphological properties of the endothelium [10,
11]. It has also been reported that certain factors such
as time of donor death to cornea harvesting and cause
of donor death may also influence endothelial
morphology [12, 13].
Some studies have reported that endothelial count
is the most important factor for donor quality.
Endothelial cell density is markedly reduced until
early puberty, especially in the first couple of years
after birth. Former studies have shown that the mean
endothelial cell count is reduced, and pleomorphism
is markedly increased after the age of 50 [14, 15].
Mean endothelial cell count is reportedly decreased by
0.3% to 0.6% each year while polymegathism and
polymorphism simultaneously increase [16, 17].
Endothelial cell density is reduced between the second
and eighth decades, dropping from 3000 to 4000
cell/mm2 on average to as low as 2600 cell/mm2 on
average. The hexagonal cell percentage also drops
from 75% to 60% [18], reducing the rate of usage of
corneas obtained from elderly donors for
transplantation. However, many studies have reported
that corneas from advanced-age donors can also be
sometimes used for transplantation, and thus donor
age does not affect donor survival. Linke et al. [17]
showed that 32.1% of corneas from donors aged over
80 years met the appropriate criteria for
transplantation. Patel et al. [19] similarly
demonstrated that 80% of corneas from advanced age
donors had suitable standards for transplantation.
According to EBAA criteria reported in 2006, donors
should be between 10 and 75 years of age [20].
Besides, the minimum medical standards set by EEBA
in 2013, as well as those set by EBAA in 2012, do not
specify an age limit for donor eligibility [7,8]. Kartal
et al. [21] reported that ECC showed a significant
negative correlation with age, being significantly
greater in the first two decades of life. Likewise, our
study revealed a negative correlation between ECC
and age. Cell count was significantly higher in the first
age group (5-19 years) compared with the second (20-
34 years), third (35-49 years), and fourth (50-65 years)
age groups. Cell count was significantly greater in the
second age group compared to the third and fourth age
groups (Table 3). Our study also demonstrated a
positive correlation between age and MCA, SD
values. SD and MCA levels were significantly lower
in the first age group compared to the second, third,
and fourth age groups. MCA was significantly lower
in the second age group compared to the 3rd and 4th
age groups, while SD was significantly lower in the
second age group than the fourth age group. CV and
hexagonality did not show any age-based differences.
Some studies in the literature failed to show any age-
associated differences in CV, MCA, and hexagonality,
although some others have reported age-related
differences in MCA [22, 23]. Kartal et al. [21] showed
that CV and MCA were significantly lower in Group
1 and 2 (0-40 years of age). In our study, mean
endothelial count was 2884.0±457.3, mean SD was
112.7±36.2, mean CV was 31.4±6.7, mean MCA was
354.3±58.4 and mean hexagonality was 61.1±8.6.
Since our mean donor age was lower than those
reported in the literature, specular microscopy findings
were ideal for transplantation in all of our donors.
Some studies investigated gender-based differences in
endothelial cell morphology, some of them reporting
ECC differences between both genders, but some
others not [24, 25]. Kartal et al. [21] reported that
female donors had a greater MCA, while a study from
India, reported higher CV in female donors [26]. Our
results did not reveal any significant difference
between both sexes. Previous studies have shown a
significant impact of time from donor death to cornea
harvesting on endothelial count [17, 27]. EBAA
recommends cornea harvesting within 20 hours in
those aged less than 50 years, and within 18 hours in
!!!!!!
!
Table 3. Time from death to harvesting (Spearman Correlation)
Cell Count
SD
CV
6A
MCA
Time from death to
harvesting (Hour)
r
-0.240
0.349
0.394
-0.191
0.224
p
0.005
0.000
0.000
0.031
0.011
SD= Standart deviation, CV=coefficient of variance, 6A=hexagonality ratio, MCA=mean cellular area,
33
Eur Res J 2016;2(1):30-35 Cornea donor data
those aged equal to or greater than 50 years of age
[20]. As a general rule, it is recommended that corneal
harvesting should be completed within 12 hours [28],
although there is still no consensus regarding the upper
limit of this time, and it may well be prolonged in
some cases [29]. Kartal et al. [21] showed that ECC
was greatest in the ≤3 hours group, although the
difference was statistically non-significant. Our study
showed a significant negative correlation between
time from death to cornea harvesting and cell count,
6A. There was, however, a significant positive
correlation between time from death to cornea
harvesting and SD, CV, and MCA.
These results suggest that donor cornea quality is
reduced as the time to the collection is increased.
However, corneal endothelial structures did not
undergo a degenerative process to preclude
transplantation since corneas were harvested within
maximum 13 hours. The harvested corneas should be
serologically tested with anti-HIV, HBsAg, anti-HCV,
and VDRL tests. Some domestic prevalence studies at
different times have found a mean HBsAg positivity
rate of 5% and a mean HCV positivity rate over 0.5%
[30].
Kocazeybek et al. [31] reported corresponding
figures of 6.6% and 0.9%. Our study revealed HBsAg
positivity in two corneas, which were disposed of. One
other cornea was disposed of by another centre due to
suspected infection.
Of the donor corneas collected by our bank over a
period of 1.5 years, 21% were used for transplantation
by our hospital and 79% by other institutions. Various
studies have reported that about 30% of donor corneas
cannot be used owing to either serological results or
an inappropriate endothelial morphology on specular
microscopy examination [8]. We suggest that, we had
a higher rate of cornea usage and we generally used
high-quality corneas, because our eye bank preferred
relatively younger donors, it rejected corneas with
suspected infection due to prolonged stay at intensive
care unit or the corneas which would be inappropriate
for transplantation due their general appearance, and
it harvested corneas at 6.7±2.9 hours on average after
donor death.
The harvested corneas were sent by our eye bank
to other clinics as soon as possible when they were not
to be used at our hospital. Time from harvesting to
transplantation was 5.2±2.8 (1-14) days on average at
other clinics.
In conclusion, we revealed that ECC, MCA, and
SD values were greater in younger donors; endothelial
morphology was altered as the time from death to
harvesting was prolonged; however, the alteration in
cell morphology was not too severe to alter transplant
success with the corneas being harvested within first
13 hours. Eye banks should meticulously work in
every step from donor harvesting to cornea
transplantation. High-risk donor corneas should not be
harvested. Harvested corneas should be examined
serologically, as well as under specular microscopy,
and they should be sent to centres of transplantation
as soon as possible.
Conflict of interest
The authors disclosed no conflict of interest during
the preparation or publication of this manuscript.
Financing
The authors disclosed that they did not receive any
grant during conduction or writing of this study.
References
[1] Thuret G, Chiquet C, Bernal F, Acquart S, Romanet JP, Mouillon M,
et al. Prospective, randomized clinical and endothelial evaluation of 2
storage times for corneal donor tissue in organ culture at 31 degrees C.
Arch Ophthalmol. 2003 Apr;121(4):442-50.
[2] Human organ and tissue transplantation. Report by the Secretariat.
Executive Board, EB112/5; 112th Session, May 2003
http://apps.who.int/gb/archive/pdf_files/EB112/eeb1125.pdf. Access
date; 2013 Sep 09.
[3] Oliva MS, Schottman T, Gulati M. Turning the tide of corneal
blindness. Indian J Ophthalmol. 2012 Sep-Oct;60(5):423-7.
[4] Turkiye Cumhuriyeti Saglik Bakanligi. Ankara: c201 2013Yılı
Guncel Bekleme Listesi Hasta Istatistikleri.
https://organ.saglik.gov.tr/web/Content.aspx?menu=%283%29guncel_
bekleme_listesi. Access date: 2013 Sep 22.
[5] Turkiye Cumhuriyeti Saglik Bakanligi. Ankara: c2013 Organ ve
Doku Dagitimi Istatistikleri.
https://organ.saglik.gov.tr/web/Content.aspx?menu=%283%29organ_v
e_doku_dagitimi_istatistikleri. Access date: 2013 Sep 09.
[6] Demirsoy N, Yilmaz A. Kornea transplantasyonunun tip, etik ve
hukuk acisindan onemi. Turkiye Klinikleri J Ophthalmology.
2012;21:171-83.
[7] European Eye Bank Association Directory. Minimum Medical
Standards. Revision 1, 2013.
http://www.europeaneyebanks.org/downloads/EEBA%20Minimum%2
0Medical%20Standards%20Rev%201%20-%202013Agreed.pdf.
Access date: 2015 Dec 18.
[8] Eye Bank Association of America. Medical Standards. Washington,
DC: EBAA; 2012.
[9] Eye Bank Association of America Medical Advisory Board. Medical
standards. Washington, DC: Eye Bank Association of America;
November 2008.
[10] Rao SK, Ranjan Sen P, Fogla R, Gangadharan S, Padmanabhan P,
Badrinath SS. Corneal endothelial cell density and morphology in
normal Indianeyes. Cornea. 2000 Nov;19(6):820-3.
[11] Abib FC, Barreto J. Behavior of corneal endothelial densityover a
lifetime. J Cataract Refract Surg. 2001 Oct;27(10):1574-8.
[12] Reinhart WJ. Eye banking methods and standards. In Krachmer JH,
34
Eur Res J 2016;2(1):30-35 Tufekci et al
Mannis MJ, Holland EJ. Cornea. Fundamentals of cornea and external
diseases. St. Louis: Mosby; 1997. P. 485-491.
[13] Grabska-Liberek I, Szaflik J, Brix-Warzecha M. The importance of
various factors relating to the morphological quality of corneas used for
PKP by the Warsaw Eye Bank from 1996 to 2002. Ann Transplant.
2003;8(2):26-31.
[14] Wilson RF, Roper-Hall MJ: Effect of age on the endothelial cell
count in the normal eye. Br J Ophthalmol. 1982 Aug;66(8):513-5.
[15] Kozer L, Manav G, Sezen F, Akova Y. Yasa bagli kornea endotel
degisimleri. T Oft Gaz. 1987;17:213-16.
[16] Yunliang S, Yuqiang H, Ying-Peng L, Ming-Zhi Z, Lam DS, Rao
SK. Corneal endothelial cell density and morphology in healthy Chinese
eyes. Cornea. 2007 Feb;26(2):130-2.
[17] Linke SJ, Eddy M, Bednarz J, Fricke O, Wulff B, Schroder A, et al.
Thirty years of cornea cultivation: long term experience in a single eye
bank. Acta Ophthalmol. 2013 Sep;91(6):571-8.
[18] McDermott ML, Atluri HKS: Kornea Endoteli. Yanoff M, Duker
JS (Eds.). BavdekT (Çeviri editörü). Oftalmoloji. İkinci baskı. İstanbul
Hayat Yayıncılık 2007; 422-30.
[19] Patel HY, Brookes NH, Moffatt L, SherwinT, Ormonde S, Clover
GM et al. The New Zealand National Eye Bank study 1991–2003: a
review of the source and management of corneal tissue. Cornea. 2005
Jul;24(5):576-82.
[20] Eye Bank Association of America. MedicalStandards. Washington,
DC: EBAA; 2006.
[21] Kartal B, Kandemir B, Akmaz B, Kugu S, Ozertuurk Y, Set T, et al.
Kartal Egitim ve Arastirma Hastanesi kornea bankasi donorlerine ait
spekuler mikroskopi verileri. Turk J Ophthalmol. 2014;44:190-5.
[22] Matsuda M, Yee RW, Glasser DB, Geroski DH, Edelhauser HF.
Specular microscopic evaluation of donor corneal endothelium. Arch
Ophthalmol. 1986 Feb;104(2):259-62.
[23] Mohammad-Salih PA. Corneal endothelial cell density and
morphology in normal Malay eyes. Med J Malaysia. 2011
Oct;66(4):300-3.
[24] Padilla MD, Sibayan SA, Gonzales CS. Corneal endothelial cell
density and morphology in normal Filipino eyes. Cornea. 2004
Mar;23(2):129-35.
[25] Hashemian MN, Moghimi S, Fard MA, Fallah MR, Mansouri MR.
Corneal endothelial cell density and morphology in normal Iranian eyes.
BMC Ophthalmol. 2006 Mar 6;6:9.
[26] Sopapornamorn N, Lekskul M, Panichkul S. Corneal endothelial
cell density and morphology in Phramongkutklao Hospital. Clin
Ophthalmol. 2008 Mar;2(1):147-51.
[27] Anderson J, Ehlers N. The influence of donor age and postmortem
time on corneal graft survival and thickness when employing banked
donor materil. Acta Ophthalmol (Copenh). 1988 Jun;66(3):313-7.
[28] Pels E, Beele H, Claerhout I. Eye bank issues: II.Preservation
techniques: warm versus cold storage. Int Ophthalmol. 2008
Jun;28(3):155-63.
[29] Kryczka T, Szaflik J, Midelfart A. Influence of donorage, post-
mortem time and cold storage on metabolic profile of human cornea.
Acta Ophthalmol. 2013 Feb;91(1):83-7.
[30] Resit M, Balık U. Turkiye’de viral hepatitlerin epidemiyolojisi.(Bir
meta analiz). In: Kılıcturgay K, ed. Viral Hepatit’98. Ankara: Viral
Hepatitle Savasim Dernegi, 1998:10-39.
[31] Kocazeybek B, Cakan H, Sansoy N, Kucukates E, Ozdemir F.
Kornea transplantasyonunda donor serolojisinin degerlendirilmesi.
Klimik Derg. 2000;13(3):101-3.
35
Eur Res J 2016;2(1):30-35 Cornea donor data
