Open Journal of Ophthalmology, 2013, 3, 76-86
http://dx.doi.org/10.4236/ojoph.2013.33019 Published Online August 2013 (http://www.scirp.org/journal/ojoph)
Outcomes of Trabeculectomy in Africa
Joella Eldie Soatiana1, Marce-Amara Kpoghoumou2, Fatch W. Kalembo3, Huyi Zhen1
1Department of Ophthalmology, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China; 2Depart-
ment of Epidemiology and Biostatistics, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China;
3Department of Maternal and Child Health, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China.
Received April 13th, 2013; revised May 14th, 2013; accepted June 20th, 2013
Copyright © 2013 Joella Eldie Soatiana et al. This is an open access article distributed under the Creative Commons Attribution Li-
cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Purpose: To determine the outcome of trabeculectomy in African countries. Design: This is a review of literature for
trabeculectomy conducted in Africa from 2000 to December 2012. Methods: We conducted an electronic search from
the following databases: PubMed, Science Direct, Google, and Google scholar websites for the articles of original stud-
ies on trabeculectomy conducted in Africa. Results: A total of 109 articles, published from 2000 to December 2012
were retrieved. Only 12 articles met our inclusion criteria and were included in the study. The follow-up duration
ranged from 6 months to 60 months. The post-trabeculectomy IOP range was 10 mmHg to 22 mmHg with rates varying
from 61.8% to 90%. The visual acuity was unchanged among 19% to 30% of the participants in the last follow-up, and
the improvement rate was 36% to 81.5% while those whose condition worsened ranged from 8.9% to 30.8%. The
cup-disc ratio was ≤0.5 in 13% and ≥0.8 in 83% of the participants. The failure rate of the c/d ratio was 0.9 and it in-
creased by 0.027 units. There was a follow-up of only one study on the visual field. Conclusion: Trabeculectomy with
or without application of antimetabolite appears to be a good way to lowering the IOP in Africa. In addition, the com-
bined effect of trabeculectomy and cataract surgery produces visual benefits for the patients.
Keywords: Trabeculectomy; Glaucoma; Africa
1. Introduction
Glaucoma is one of the most common causes of blind-
ness in the world [1] and it causes irreversible visual loss
[2]. This aspect is well known for the developed
countries, however in Africa blindness mainly occurs due
to cataract, trachoma and onchocercosis. Glaucoma is not
mentioned enough. Patients present with severe findings
after a long-lasting history of disease [1]. Data available
from the United States and Barbados suggest that blacks
(mostly of West African origin) are 4 - 8 times more like-
ly to have glaucoma than whites and more likely to be
blind due to glaucoma compared with the white popula-
tion [3,4]. Treatment is difficult due to the unavailability
and expensiveness of glaucoma medication [5]. This ma-
kes surgery for glaucoma an attractive option. Trabecu-
lectomy is also a well recognized treatment option for the
surgical management of raised intraocular pressure (IOP)
[6]. It has been reported to be more beneficial in Africans
in terms of IOP lowering effect and slowing down of
field loss [7,8] and has been reported to have some
benefit in black people in Africa and the Caribbean area
[9,10]. Wound healing modulating agents, usually anti-
metabolites like 5-Fluorouracil and Mitomycin C which
inhibit the natural healing response and scar formation
are used to reduce trabeculectomy failure [11]. Primary
trabeculectomy with MMC using a fornix-based conjun-
ctival flap technique is an effective treatment for Thai
glaucoma patients. Mean IOP was significantly decrea-
sed from 26.1 + 11.7 mmHg to 11.7 + 4.4 mmHg (p <
0.001) at the last visit. At the last follow up period, 67
eyes (97.1%) were considered as success [12]. Wilkins and
Wormald and their respective colleagues reported that
the addition of antimetabolites to trabeculectomy reduced
IOP among participants enrolled in their studies [13].
We decided to perform a systematic review in order to
determine the outcome of trabeculectomy in African
countries.
2. Materials and Methods
2.1. Search Strategy
A search strategy was designed to identify publications

Outcomes of Trabeculectomy in Africa 77
which described trabeculectomy in Africa. The search
was conducted from November to December 2012. We
conducted an electronic search from the following
databases: PubMed, ScienceDirect, Google, and Google
scholar websites. The following search terms were used
“trabeculectomy in Africa”, “treatment of glaucoma in
Africa”, “follow-up of trabeculectomy in Africa”.
2.2. Inclusion/Exclusion Criteria
Articles were included in the review if they met the
following criteria: 1) they were conducted in Africa and
covered trabeculectomy in Africa; 2) they covered our
objective; 3) they were published in English; 4) they
were published from 2000 to December 2012. Articles
were excluded from the review if: 1) they were
conducted outside African countries; 2) the trabeculec-
tomy conducted in Africa was associated with another
surgery other than cataract surgery; 3) the articles were
conducted in Africa and covered trabeculectomy in
Africa but we did not have access to the full text. Types
of outcome measures: The main outcome measures of the
study were intraocular pressure (IOP) reduction, visual
acuity (VA), visual field (VF) and cup-disc (c/d) ratio.
2.3. Data Extraction
Two authors independently viewed the titles and abstra-
cts of all the studies identified in the electronic searches.
All methodological steps followed the guide- lines set by
QUOROM statement criteria [14]. The full copies of all
possibly relevant studies were obtained and indepen-
dently inspected by two authors to determine whether
they met the inclusion criteria. When a difference in
opinion occurred, a third reviewer was consulted, as an
arbiter. The authors of the selected studies were con-
tacted to elucidate any doubts, when necessary. Included
articles were studied for relevance and content. Data was
extracted under the following areas: first author, year of
publication, country of study, study population, study
objectives, research methods and interventions. The main
findings of each study were summarized.
2.4. Data Analysis
The data for analysis and synthesis were the study me-
thods, findings, and conclusion.
3. Results
3.1. Eligible Studies
For trabulectomy outcomes in Africa, articles were re-
trieved based on the search criteria above. Study selec-
tion process is shown in Figure 1. The electronic sear-
ches retrieved 109 citations, all citations were screened
and 30 full text articles were retrieved for further as-
sessment. A total of 18 articles were excluded because
they were not conducted in sub-Saharan Africa, some of
them were not about trabeculectomy in Africa and a
number of them were not published in English. Finally, a
total of 12 studies including 947 patients were eligible
for the review. Study characteristics are summarized in
Table 1.
3.2. Main Outcomes
Articles reviewed were drawn from 5 sub-Saharan coun-
tries (Nigeria, South Africa, Tanzania, Ghana, and
Kenya). There were 2 articles which used 5 FU during
surgery [15,20], 2 articles used mitomycin C during the
surgery [17,23], 3 articles did not use the antimetabolite
during the surgery [11,18,21], 5 articles were on com-
parative study, of those 4 compared between using 5FU
and non antimetabolites surgeries [16,19,22,24] and 1
was on comparison between using these 2 antimetabo-
lites (5FU and MMC)[25]. Among the articles, 4 were on
trabeculectomy combined with cataract surgery [15,20,
23,24]. The duration of the last follow-up was 6 months
to 60 months. The outcomes of the study were: 1) out-
come of IOP post-trabeculectomy; 2) outcome of VA
post-trabeculectomy; 3) outcome of the cup-disc ratio
and the visual field post-operative.
 Outcome of IOP post-trabeculectomy. There was a
success during the control of IOP for all the studies
with a range of 10mmHg to 22 mmHg and the rates
varied from 61.8% to 90%.
 Outcome of VA post-trabeculectomy. The VA was
unchanged among 19% to 30% of the participants in
the last follow-up, VA improvement rate was between
36% to 81.5% and worsened in 8.9% to 30.8% of the
Figures 1. Flow chart of study selection based on the inclu-
sion and exclusion criteria.

Outcomes of Trabeculectomy in Africa 78
Table 1. Summary of studies of the outcome of trabeculectomy in Africa.
First
author,
area, year
Study
population Study design and methodology Interventions Outcomes
A.Lawan,
Nigeria,
2007 [15]
71 eyes,
63 patients
POAG
Retrospective
Trabeculectomy with
application of antimetabolite.
21% of them associated with
cataract surgery
VA as measured with
Snellen`s or,Illiterate “C”
c/d ratio was assessed with
direct ophthalmoscope.
IOP was measured with the
applanation tonometer
Perimetry was done with the
2 m Tangent screen using a
5 mm white target
Administration of 5FU as
antimetabolite
Good intraocular pressure contro 82% of
participants had IOP of 10 to 15mmHg, 15% had
16 to 20 mmHg. 19% of the patients had VA of 6/6 -
6/18 before and after surgery, 51% had visually
impaired after surgery, 29% had severe visual
impairement and 1% was blind. 13% had c/d ratio ≤
0.5, 54% had c/d ratio = 0.6 - 0.8 and 33% had c/d
ratio = 0.9. The perimetry result showed that 7% of
the participants had peripheral field constriction of
10 - 20˚, 27% had both peripheral field constriction
and arcuate scotoma, 48% had visual field of 30˚
and less (≤30˚) and 18% had ability to fixate on
target.
Adegbehingbe
B.O, Nigeria,
2007 [16]
53 patients
with
87.5%:
primary
glaucoma
and 12.5%
secondary
glaucoma
Retrospective IOP was
measured and followed-up
from day 1 to 12 months.
26.4% of the patients had
trabeculectomy with
application of
antimetabolite, 73.59%
had trabeculectomy
without application of
antimetabolite.
The outcome of the
surgery was classified as
complete success if post
operative IOP at one year
was 20 mmHg or less
without anti-glaucoma
medication
Measuring of VA and IOP
Administration of 5FU as
antimetabolite
Complete success was obtained in 61.8% of the
participants at 12 months. High success rate for the
both. The mean post-operative IOP in the
5FU-augmented cases was significantly lower
compared with the non augmented cases
(P = 0.005). There were no significant changes in
the VA during the follow-up period.
Manners T,
South Africa,
2001 [17]
43 eyes 41
patients
Traumatic
angle
recession
glaucoma
Retrospective
Trabeculectomy with
application of antimetabolite.
The last follow-up was at
60 months postoperative
with a mean of 25
months. The outcome of
the surgery was classified
as “complete success”
when the IOP was <21
mm Hg without
glaucoma medication
Measuring of VA and IOP
Administration of MMC as
antimetabolite
At last follow-up, there was 76.7%
of complete success for the IOP.
For the VA, at last follow-up
ranged from 6/9 to no
light perception, the visual
outcome was the same or
better in 81.5%.
Joy Kabiru,
Tanzania,
2005 [18]
-
Retrospective 36% of the
participant had
trabeculectomy with
application of antimetabolite.
Mean follow-up was 8
months.
Measuring of VA and IOP
Administration of 5FU as
antimetabolite
73% had IOP of 15 mm Hg or less at latest
follow-up (mean follow-up was 8.7 months) and
90% had IOP of 21 mm Hg or less
(mean follow-up was 8.8 months).
25% patients lost VA at least 2 lines
of Snellen acuity or equivalent
between preoperative
measurement and latest follow-up.

Outcomes of Trabeculectomy in Africa 79
Continued
Gyasi M.E.,
Ghana, 2006
[11]
191 eyes
164
patients
96.8%
POAG
3.2%
normal
tension
glaucoma
(NTG)
Retrospective
Trabeculectomy without
application of antimetabolite
Follow-up period was
grouped into 4 categories: the
first post-operative month,
between the second and
third months, fourth to
fifth month and the sixth
month and beyond Control
IOP was only made in POAG
patient. Successful IOP
control defined as IOP less
than 22 mmHg or a reduction
of 30% if pre-operative
pressure was already less
than 22 mmHg.
IOP was measured with
standard Goldman
applanation tonometer
Statistically significant difference between the mean
pre-op and post-op IOP (p = 0.001) with success of
88.46% of the eyes which had post-operative IOP <
22 mmHg at the last examination at six months.
In eyes with NTG only 16.7% achieved a successful
30% target pressure reduction with post-op IOP of
8 mmHg.
Yorston D,
Kenya, 2001
[19]
68 eyes
68 patients
Chronic
open angle
glaucoma
Prospective Some patients
had trabeculectomy with
application of antimetabolite.
Major outcome measures
were IOP at 6 months
and probability of failure at 2
years. Failure was defined as
a pressure of more than 26
mm Hg on one occasion,
or a pressure of between
22 and 26 mm Hg on two
occasions at least 2 months
apart.
Measuring of IOP and VA
Administration of 5FU as
antimetabolite
The mean IOP was 17.4 mm Hg in the placebo
group and 16.9 mmHg in the 5-FU group after 180
days of surgery.
By 2 years after trabeculectomy, the probability of
successful IOP control was 70.6% in the placebo
group, and 88.8% in the 5-FU group.
Among patients followed for 2 years, 30% lost 0.3
logMAR units of visual acuity.
Bowman RJC,
Tanzania,
2010 [20]
163 eyes
163
patients
with
Advanced
glaucoma
Retrospective 80%
Trabeculectomy
combined with cataract
surgery with application
of antimetabolite. IOP
outcomes were analysed
using two success criteria:
follow-up IOP ranges of
6 - 15 and 6 - 20 mmHg.
Measuring VA and IOP
Administration of 5FU as
antimetabolite
Of those with at least a 6-month follow-up, 58%
patients and 84% patients had IOPs of 6 - 15 and
6 - 20mmHg, respectively.
Mean follow-up IOP was 15 mmHg. There was no
significant difference in mean final follow-up IOP
between those with and without 3 or 6 months of
follow-up.
70% patients had improved their acuity compared
with pre-operation by at least one line; 40 (37%)
achieved 6/18 or better, and 71
66% achieved 6/60 or better. Of those with at least
3- and 6-month follow-up, 42 of 51 (82%) patients
and 17 of 20 (85%) improved their acuity
Anand N,
Nigeria, 2001
[21]
142 eyes
100
patients
POAG
(84%
advanced
glaucoma)
Retrospective
Trabeculectomy without
application of antimetabolite.
Subsequent surgery for
glaucoma and cataract
was noted. Follow-up more
than 6 months Criteria for
success were an lOP reduction
of more than 30% from
pre-operative levels, a
permanent decrease in
visual acuity of 2 Snellen
chart lines or less from
pre-operative levels and
lOP of less than either 22
mmHg (criterion 1) or 16
mmHg (criterion 2) with
or without medication.
Measuring of VA and IOP
The cumulative success rates by the first criterion
were 85% at the end of 1 year, falling to 71% in 5
years. By the second criterion success rates were
much lower, being 65% at 1 year and 46% at 5
years.
Failure of surgery was most frequently in the first 6
months after surgery but continued at a steady rate
throughout the follow-up period.

Outcomes of Trabeculectomy in Africa 80
Continued
Gyasi M.E.,
Ghana, 2006
[11]
191 eyes
164
patients
96.8%
POAG
3.2%
normal
tension
glaucoma
(NTG)
Retrospective
Trabeculectomy without
application of antimetabolite
Follow-up period was
grouped into 4 categories: the
first post-operative month,
between the second and
third months, fourth to
fifth month and the sixth
month and beyond Control
IOP was only made in POAG
patient. Successful IOP
control defined as IOP less
than 22 mmHg or a reduction
of 30% if pre-operative
pressure was already less
than 22 mmHg.
IOP was measured with
standard Goldman
applanation tonometer
Statistically significant difference between the mean
pre-op and post-op IOP (p = 0.001) with success of
88.46% of the eyes which had post-operative IOP <
22 mmHg at the last examination at six months.
In eyes with NTG only 16.7% achieved a successful
30% target pressure reduction with post-op IOP of
8 mmHg.
Yorston D,
Kenya, 2001
[19]
68 eyes
68 patients
Chronic
open angle
glaucoma
Prospective Some patients
had trabeculectomy with
application of antimetabolite.
Major outcome measures
were IOP at 6 months
and probability of failure at 2
years. Failure was defined as
a pressure of more than 26
mm Hg on one occasion,
or a pressure of between
22 and 26 mm Hg on two
occasions at least 2 months
apart.
Measuring of IOP and VA
Administration of 5FU as
antimetabolite
The mean IOP was 17.4 mm Hg in the placebo
group and 16.9 mmHg in the 5-FU group after 180
days of surgery.
By 2 years after trabeculectomy, the probability of
successful IOP control was 70.6% in the placebo
group, and 88.8% in the 5-FU group.
Among patients followed for 2 years, 30% lost 0.3
logMAR units of visual acuity.
Bowman RJC,
Tanzania,
2010 [20]
163 eyes
163
patients
with
Advanced
glaucoma
Retrospective 80%
Trabeculectomy
combined with cataract
surgery with application
of antimetabolite. IOP
outcomes were analysed
using two success criteria:
follow-up IOP ranges of
6 - 15 and 6 - 20 mmHg.
Measuring VA and IOP
Administration of 5FU as
antimetabolite
Of those with at least a 6-month follow-up, 58%
patients and 84% patients had IOPs of 6 - 15 and
6 - 20mmHg, respectively.
Mean follow-up IOP was 15 mmHg. There was no
significant difference in mean final follow-up IOP
between those with and without 3 or 6 months of
follow-up.
70% patients had improved their acuity compared
with pre-operation by at least one line; 40 (37%)
achieved 6/18 or better, and 71.
66% achieved 6/60 or better. Of those with at least
3- and 6-month follow-up, 42 of 51 (82%) patients
and 17 of 20 (85%) improved their acuity.
Anand N,
Nigeria, 2001
[21]
142 eyes
100
patients
POAG
(84%
advanced
glaucoma)
Retrospective
Trabeculectomy without
application of antimetabolite.
Subsequent surgery for
glaucoma and cataract
was noted. Follow-up more
than 6 months Criteria for
success were an lOP reduction
of more than 30% from
pre-operative levels, a
permanent decrease in
visual acuity of 2 Snellen
chart lines or less from
pre-operative levels and
lOP of less than either 22
mmHg (criterion 1) or 16
mmHg (criterion 2) with
or without medication.
Measuring of VA and IOP
The cumulative success rates by the first criterion
were 85% at the end of 1 year, falling to 71% in 5
years. By the second criterion success rates were
much lower, being 65% at 1 year and 46% at 5
years.
Failure of surgery was most frequently in the first 6
months after surgery but continued at a steady rate
throughout the follow-up period.

Outcomes of Trabeculectomy in Africa 81
Continued
Ashaye AO,
Nigeria, 2009
[22]
76 eyes 44
patients
92,1%
POAG
7.9%
chronic
angle
closure
glaucoma
Retrospective 32.9% had
trabeculectomy with
application of
antimetabolite and 67.1%
had trabeculectomy
without antimetabolite
Follow-up for minimum
of 12 month after surgery
Measuring of IOP
Administration of 5FU as
antimetabolite
The percentage of maintaining IOP of 21 mmHg or
less at 1 year of follow-up was 79.4%. (80.6% for
the non-5-FU group and 76.7% for the 5-FU group.)
Comparison of the curve by the log-rank test
showed no significant difference between the two
groups (p = 0.136).
Harry A
Quigley,
Tanzania,
2000 [23]
21 patients
-
Prospective Visual acuity was
measured at 4 metres using a
tumbling E ETDRS chart.
Visual field was measured
using the Dicon LD400
automated instrument IOP
was measured with calibrated
TonoPen Optic disc area
examined with a hand held,
78 dioptre lens and 10 x eye
piece of the slit lamp. 80% of
the patients had
trabeculectomy with
application of antimetabolite
25% combined with cataract
surgery 45% had iridectomy
Follow-up of participants was
till 3years after surgery
Measuring of VA, IOP
Examination of optic disc
Administration of MMC as
antimetabolite
88% of eyes were examined at 3 years.
IOP declined from 29.9 mm Hg to 14.7 mm Hg at 3
years, with 89% achieving a reduction of 25% or
more.
The mean c/d ratio increased by only 0.027
units (0.66 (0.25) to 0.69 (0.22), p = 0.8, n = 13
eyes). The c/d ratio worsened by 0.05 units or more
in four eyes, improved by 0.05 or more in three
eyes, and was unchanged in the remainder.
Among the yes with trabeculectomy alone, visual
acuity was essentially unchanged in five
eyes, improved by one or more line in four
eyes, and was worse in eight eyes
Mielke C,
Nigeria, 2003
[24]
154 eyes
101
patients
-
Retrospective Trabculectomy
with 2 groups of patients:
group that received
intraoperative antimetabolite
and control group. Subsequent
surgery for glaucoma and
cataract was noted.
Average follow-up was
17 ± 2.18 months. Major
outcome measures were an
IOP reduction of more than
30% from preoperative levels,
a permanent decrease in
visual acuity of two or
less Snellen-chart lines
from preoperative levels
and:
1. IOP 20 mm Hg or less with
or without medication.
2. IOP less than 14 mmHg
with or without medication.
Measuring VA and IOP
Administration of 5FU as
antimetabolite
When an IOP of 20mmHg or less was defined as
success, 76% of the 5-FU group and 79% of the
control group were successful at 18 months.
Comparison of survival curves did not show any
significant difference by the log-rank test (p = 0.55).
When success was defined as an IOP of 14 mmHg,
the probability of success was 64% for the 5-FU
group and 39% for the control group at 18 months.
This difference was significant by the log-rank test
(p = 0 .018).
5.1% of the control group and 8.9% for the 5FU
group lost more than two lines of Snellen-chart
visual acuity and the difference was not statistically
significant (p = 0.49).
Nitin Anand,
Nigeria, 2012
[25]
132 eyes
129
patients
Primary
trabeculect-
omy
Retrospective 73 eyes had
trabeculectomy with
application of antimetabolite.
Two criteria for success
were used for survival
analyses. IOP of less than 19
and 15 mmHg, a decrease of
20% from preoperative IOP
were used for Kaplan–Meier
survival analyses.
Measuring of VA, IOP
Administration of 5FU and
MMC as antimetabolite
The 5-FU group had longer mean follow-up of
53 ± 26 months than the MMC group (38 ± 18
months, p < 0.001). The MMC group had
significantly lower pressures at all postoperative
visit except between 30 and 35 months (p = 0.07).
The probability of maintaining an IOP less than 19
mmHg and 15 mmHg without additional medication
or needle revisions at 2 and 3 years postoperatively
was 71% and 64% respectively for the 5FU group and
81% and 79% respectively for the MMC group.
The MMC group had significantly better survival
times, both for IOP less than 19 mm Hg (p = 0.03)
and IOP less than 15 mm Hg (p = 0.006).
At last follow up, 40 eyes (30.3%) had lost more
than 2 lines of Snellen visual acuity, 24 from 5-FU
and 16 from the MMC group (p = 0.8).
c/d ratio = cup-disc ratio; IOP = intraocular pressure; VA = visual acuity; 5FU = 5 fluorouracil; MMC = mitomycin C; POAG = primary open angle glaucoma;
NTG = normal tension glaucoma.

Outcomes of Trabeculectomy in Africa 82
participants.
 Outcome of the cup-disc (c/d) ratio and the visual fie-
ld post-operative. The follow-up of the c/d was only
found in 3 studies. In these cases, the c/d ratio was
≤0.5 in 13% and ≥0.8 in 83%. There was a failure on
the c/d ratio of 0.9 and this increased by 0.027 units
[23].
And for the visual field, there was a follow-up for only
one study.
4. Discussion
Trabeculectomy is the most common operative procedure
for the treatment of medically uncontrolled glaucoma. It
remains the mainstay of treatment for black glaucoma
patients especially those of African origin due to the un-
availability and high cost of topical therapy [26,27].
The findings of our review revealed that rates of IOP
between 10 mmHg - 22 mmHg ranged from 61.8% to
90% in the reviewed articles. The criteria of the complete
success of IOP were different for each study but all of
them had significant complete success of more than 50%.
Depending on the trabeculectomy with augmentation or
not, all of them had a success result despite some authors
suggesting that in African patients, a successful outcome
of trabeculectomy may be compromised by an aggressive
healing response [28,29]. Therefore, antimetabolites such
as 5-FU or MMC can be used [30] as found by Adeg-
behingbe in Nigeria in which the mean post-operative
IOP in the 5FU-augmented cases was significantly lower
compared with the non augmented cases (p = 0.005) [16].
A study conducted by Yorston in Kenya found that the
placebo group was 2.18 times (95% CI 0.67 to 7.15)
more likely to require additional IOP lowering proce-
dures than the 5-FU group [19]. In another study con-
ducted by Anand et al. in Nigeria trabeculectomy without
antimetabolite use appeared to be an effective way to
lower the IOP of advanced glaucoma to less than 22
mmHg but not to less than 16 mmHg [21]. From these
results, regardless of the trabeculectomy being with or
without augmentation of antimetabolite, combined or not
with cataract surgery, it appears to be a good way to
lowering the IOP in Africans. The results of this study
are consistent with findings from elsewhere, for instance,
Ioannis Kyprianou et al. found that with the longest fol-
low-up period, trabeculectomy augmented with MMC
under the scleral flap in difficult cases can achieve good
long-term IOP control [31]. Leyland M et al. found that
the effect of 5FU has been reported with conflicting re-
sults such as showing no significant effect in other popu-
lations [32]. Wang Mei et al. showed that phacotrabe-
culectomy and trabeculectomy treatments exhibit similar
IOP reduction, successful rates, and complications when
it comes to treating PACG patients with coexisting cata-
ract [33]. In addition, Vizzeri G and Weinreb RN showed
that surgical alternatives combined with cataract extrac-
tion may be utilized to achieve a more significant IOP
reduction [34].
The results of ROTCHFORD A showed that the success
rates of trabeculectomy were lower than those reported in
developed countries, the difference may be attributed to
differences in surgical technique and postoperative in-
terventions such as suture removal/lysis, manipulation of
the bleb, and tailored steroid dosage [35].
Argon laser trabeculoplasty (ALT) may have lower
long term IOP lowering effect in blacks than whites [36].
Blacks have higher risk of ALT failure than whites [37].
In any case lasers are hard to come by in African setting.
The VA was unchanged among 19% to 30% of the
participants in the last follow-up, VA improvement rate
was between 36% to 81.5% and worsened in 8.9% to
30.8% of the participants. Combined surgery produce
visual benefit for most patients with similar pressure
control to pure trabeculectomy [20]. The large prospec-
tive studies such as Ocular Hypertension Treatment
Study (OHTS) [38], Collaborative Normal Tension Glau-
coma Study (CNTGS)[39] and Early Manifest Glaucoma
Treatment Study (EMGTS) [40] have demonstrated that
lower IOPs are associated with reduced risk for progress-
sion of visual field damage and visual loss [41]. Ioannis
Kyprianou et al. found the main reason for reduced vi-
sion was pre-existing co-morbidity and development of
lenticular opacities [31]. In a study conducted by Stal-
mans et al., no change in visual acuity was noted: visual
acuity before and at 1 month postoperatively was 0.67
(0.3) (range 0.01 - 1) and 0.61 (0.3) (range 0.02 - 1.0; p =
0.25) on average [42]. Visual loss of more than two
Snellen-chart lines was observed in a significant propor-
tion of patients who had primary trabeculectomy in a
Nigerian population [43]. Bekibele found a statistically
significant decrease in visual acuity post-operatively [27].
Brian A. et al., Law SK found snuff-out (or severe long-
term unexplained vision loss after trabeculectomy with
mitomycin C treatment [44-46] and the risk factor for
long-term vision loss was preoperative split fixation on
VF. Transient vision loss is common and may take up to
2 years for recovery [44].
The results of the review also indicate that the fol-
low-up of the c/d was found in 3 studies. In these cases,
the c/d ratio was ≤0.5 in 13% and ≥0.8 in 83%. There
was a failure on the c/d result from 0.9 or worse and in-
creasing by 0.027 units [23]. Mielke C et al showed 70%
of eyes had advanced glaucomatous optic disc cupping or
visual field loss affecting central vision [24]. Kotecha
and coworkers identified “significant” increases in rim
volume at 2 years following surgical operations which
produced a fall in pressure of around 30%. The reversal
of disc cupping following trabeculectomy can be present
up to 2 years after pressure reduction [47]. Reversal of

Outcomes of Trabeculectomy in Africa 83
optic disc cupping following intraocular pressure reduc-
tion is a well known phenomenon [48] and changes seen
in juvenile glaucomas are more pronounced than those
found in adult patients [49,50]. The clinical significance
of these disc changes appears to be unclear, although
reports have suggested that there may be an associated
improvement of visual function that corresponds to this
improvement in disc appearance [39,51-54]. But a study
by Park et al. described short-term (follow-up of two
months) reversal of optic disc cupping documented by
Heidelberg Retina Tomograph (HRT) in adult glaucoma
patients (mean age of 59.3 ± 9.1 years) after IOP reduc-
tion following trabeculectomy [55]. And Swinnen et al.
documented two young-adult patients (33-year-old and
14-year-old) with reversal of optic disc cupping after
trabeculectomy lasted for 6 and 36 months respectively
and showed an improvement of cup to disc area ratio on
HRT [56].
There was a follow-up for only one study on visual
field in our review. Blacks of all ages had worst visual
fields than whites when 60˚ Humphrey’s visual field was
tested [57]. The progression of visual field loss is higher
in blacks than whites [58]. Visual fields remained stable
in 73.3% of cases during the follow-up period [59]. In
any case diagnosis of visual field progression remains
difficult, particularly in eyes with advanced field loss,
due to long-term fluctuation of fields [60]. A study of
Swinnen S et al. documented two young-adult patients
(33-year-old and 14-year-old) who showed an improve-
ment in visual field for at least 3 months after trabe-
culectomy for the first patient and the second patient for
3 years [56].
The facts that mean IOPs of 14 mmHg can result in
stable visual field has been concluded from several major
clinical studies [61,62]. Moreover, IOP fluctuations are a
known risk factor for visual field progression [63]. Any-
way careful postoperative follow-up observation of the
visual field remains necessary even after successful sur-
gical pressure reduction [64].
The study has the following limitations; the review
only included articles of studies conducted in only five
African countries as such the findings of the study cannot
be generalized to the entire African population. Poor ac-
ceptance of the surgery and late presentation of patients
to the hospital also affected the outcomes trabeculectomy
among the studies included in this review. The IOP at
presentation was high in most of the patients [65]. One
third of the patients had c: d ratio of 0.9 at presentation
[66]. Even those who presented earlier and despite in-
tense effort at health education on the nature of the dis-
ease, it was difficult to convince some patients that the
eye that could see far well had a potentially sight threat-
ening disease [66]. Peter R Egbert found that patients are
often put off or refuse surgery until they have severe vi-
sion loss [67]. A Tanzanian study, found that only 46%
of patients accepted trabeculectomy even though they
were offered free surgery, hospitalization, and food [2].
In interactions and discussions made by Peter R Egbert
with West African ophthalmologists showed that one
finds an understandable reluctance to do trabeculecto-
mies because of poor patient acceptance, the difficulty of
postoperative care, and uncertain results. In fact, most
ophthalmologists do no glaucoma surgery [67]. Another
limitation of the study was that only studies published in
English language were included in the study. We might
have left out some studies conducted in other languages
which might have contributed significantly to our study.
Furthermore, the duration of follow-up was short and
differed across the studies included in the review. The
follow-up period was short and drop-out rate was sig-
nificantly high but these were beyond our control [68].
The problem of loss to follow-up in Africa seems to have
started long time ago. In 1979 and 1990, Thommy CP et
al. and Verry JD already concluded that “One of the big-
gest problems in most studies is the lack of adequate fol-
low-up” [69,70].
5. Conclusion
Trabeculectomy with or without application of antime-
tabolite appears to be a good way of lowering the IOP in
Africa. In addition, combining trabeculectomy with cata-
ract surgery produces visual benefit for the patients.
There is a need for African countries to adopt ways of
improving and expanding the duration of follow-up of
post-operative patients. More longitudinal studies are
also needed on outcomes of trabeculectomy in most of
the African countries in order to have enough evidence on
the effectiveness of the procedure. Educating the popula-
tion on the severity of glaucoma is also warranted. Prac-
titioners should also be motivated to do fundoscopy and
identify optic disc cupping and refer in time the sus-
pected cases to the ophthalmologists. Furthermore, the
practitioners and opthalmologists should be offered con-
tinuous training on trabeculectomy.
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