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A Meta-analysis
on the clinical efficacy and safety of optic capture in pediatric cataract
surgery
Hong-Wei Zhou1, Fang Zhou2,3
1Department
of Ophthalmology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei
Province, China
2Department
of Statistics, Stockholm University, Stockholm SE-106 91, Sweden
3College
of Urban Economics and Public Administration, Capital University of Economics
and Business, Beijing 100070, China
Correspondence
to: Fang Zhou. College of Urban Economics and
Public Administration, Capital University of Economics and Business, Fengtai
District, Beijing 100070, China. zhoufang_1122@163.com
Received: 2015-07-17 Accepted:
2015-10-25
Abstract
AIM: To evaluate the
clinical efficacy and safety of optic capture in pediatric cataract surgery.
METHODS:
Searches of peer-reviewed literature were conducted in PubMed, Embase and the
Cochrane Library. The search terms were “optic capture” and “cataract”. The
retrieval period ended in December 2014. Relevant randomized controlled trials
(RCTs), case-control studies and cohort studies were included. Meta-analyses
were performed. Pooled weighted mean differences and risk ratios with 95%
confidence intervals were estimated.
RESULTS:
Ten studies involving 282 eyes were included, 5 of which were RCTs involving
194 eyes. The application of optic capture significantly reduced both opacification
of the visual axis (RR: 0.12; 95% CI: 0.02 to 0.85; P=0.03) and occurrence of geometric decentration (RR: 0.09; 95% CI:
0.02 to 0.46; P=0.004). But it did
not significantly affect best corrected visual acuity (BCVA) (WMD: -0.01;
95%CI: -0.07 to 0.05; P=0.75) and influence
the occurrence of posterior synechia (RR: 1.53; 95% CI: 0.84 to 2.77; P=0.17). Deposits in the anterior
intraocular lens were significantly increased in the optic capture group early
after surgery (RR: 1.40; 95% CI: 1.05 to 1.86; P=0.02) and at the last follow-up (RR: 2.30; 95% CI: 1.08 to 4.92; P=0.03). The quality of the evidence was
assessed as high.
CONCLUSION:
The application of optic capture significantly reduces opacification of visual
axis and occurrence of geometric decentration but do not significantly
improve BCVA with notable safety.
KEYWORDS:
optic capture; intraocular lens; pediatric cataract; secondary opacification;
Meta-analysis
DOI:10.18240/ijo.2016.04.20
Citation:
Zhou HW, Zhou F. A Meta-analysis on the clinical efficacy and safety of optic
capture in pediatric cataract surgery. Int
J Ophthalmol 2016;9(4):590-596
INTRODUCTION
Opacification of the visual axis after pediatric
cataract surgery is a serious complication. It is potentially induced by the
proliferation and migration of the remaining lens epithelial cells (LEC) after
surgery. Thereby blocking the visual axis and typically causing visual acuity
assessed by Snellen chart to decrease by at least 2 lines[1]. The discovery of new methods to prevent the
opacification of the visual axis after pediatric surgery is a subject of
ongoing research. The elimination of the secondary opacification is an
important indicator of the success of pediatric cataract surgery[2]. Several techniques have
been applied to inhibit the phenomenon, including posterior continuous
curvilinear capsulorhexis (PCCC) combined with anterior vitrectomy before or
after the implantation of the intraocular lens (IOL)[2-3], PCCC alone and bag-in-the-lens implantation[4]. Kohnen et al[5] and Gimbel[6]
invented optic capture in 1994, and the technique, which consists of PCCC and
optic capture through the posterior capsulorhexis, has become popular and
average. An increasing number of authors believe that this procedure helps to
maintain the centration of the IOL and prevents opacification of the visual
axis. After the development of this technique, numerous clinical trials were
conducted, but certain debates have lingered. Some authors do not consider the
application of optic capture in pediatric cataract surgery to be useful and
safe. And their clinical trials are in general quality. For example, Vasavada and
Trivedi[7] reported that
all eyes in the optic capture group and no-optic capture group maintained a
clear visual axis in a prospective study comprising 40 eyes. The study
demonstrated significantly increased posterior synechia formation in the optic
capture group compared with the no-optic capture group, and 1 eye in the
optic-capture group developed a membrane in front of the IOL. In another study,
Koch and Kohnen[8]
reported that anterior vitrectomy was the only effective method for preventing
or delaying secondary cataract formation in infants and children. All optic
capture cases without vitrectomy also remained clear initially; however, after
6mo, 4 out of 5 cases developed opacification. This study was performed on a
small scale and was not randomized. Other studies were also small, and the
numbers of enrolled eyes ranged from 13[6]
to 50[9]. Furthermore, no
technique is perfect. For example, the disadvantage of PCCC with anterior
vitrectomy is vitreous incarceration in the wound, which increases the risk of
retinal detachment[1-2].
Anterior vitrectomy at the time of cataract surgery also increases the risk for
cystoid macular edema (CME)[3],
however, the incidence of CME in children has been reported to be low[4]. These disadvantages
could be avoided if a technique could serve as a substitute for anterior
vitrectomy. Thus, research on relevant topics is very meaningful.
The accuracy of conclusions from many previous
clinical trials remains uncertain because these trials did not adopt random
methods. Furthermore, it is unclear whether the application of optic capture in
pediatric cataract surgery can significantly reduce secondary opacification of
the visual axis and geometric decentration due to the small sample sizes of
individual studies. As we all know, the quality of multi-center clinical trial
and Meta-analysis rank first in evidence based medicine. Multi-center clinical
trial is time-consuming and costly. Thus, a systematic review and Meta-analysis
can elucidate the benefits of optic capture.
MATERIALS AND
METHODS
This review was conducted and reported according to
the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA)
statement issued in 2010[10].
Systematic
Literature Search Comprehensive
searches of peer reviewed literature were conducted using PubMed (ended in Dec.
2014), Embase (ended in Dec. 2014), Cochrane Library (ended in Dec. 2014). The
search terms, including MeSH words and text words, were “optic capture” and
“cataract”. Overall, 58 papers were obtained from PubMed, 61 from Embase, 20
from Cochrane library. All the papers had abstracts or full texts written in
English.
Inclusion and
Exclusion Criteria For
inclusion, studies had to meet the following criteria: 1) pediatric cataracts
were diagnosed, and the patients in optic capture group and no-optic capture
group were comparable; 2) the study contained at least an optic capture group
and a no-optic capture group, and PCCC was performed in every eye of the two
groups; 3) the study was required to be a clinical trial, including cohort
studies, case control studies or randomized controlled studies, with suitable
methods and designs; 4) at least one of the primary outcomes [secondary
opacification, best-corrected visual acuity (BCVA)] or secondary outcomes
(posterior synechia, deposits in the anterior IOL, decentration of IOL) was
evaluated. Studies were excluded if any of the following criteria were met: 1)
the study concerned irrelevant topics or was repeatedly included in several
databases; 2) the study contained no original data (reviews, comments or letters);
3) the study was a case series report; 4) a significant heterogeneity in age
existed between study groups, for example the study groups were divided
according to age.
Data Extraction
and Quality Assessment To avoid bias in the data extraction
process, two investigators independently extracted and collected data following
the selection criteria described above. Any discrepancy was resolved by
discussion and consensus. The following information was extracted from each
trial: first author's name, publication year, type of study, the number of
treated patients, duration of follow-up, patients’ ages, the number of eyes
with secondary opacification, BCVA, the number of occurrences of geometric
decentration of IOL, the number of eyes with deposits in the anterior IOL early
after surgery, the number of eyes with posterior synechia and
the number of eyes with deposits in the anterior IOL at the last follow-up.
Quality assessment of the evidence was performed by GRADE.
Statistical
Analysis To
evaluate the efficacy and safety between the optic capture group and no-optic
group for the treatment of pediatric cataract, we assessed the overall effect
of optic capture and no-optic capture from the data of the included studies and
used the pooled weighted mean differences (WMDs) and risk ratios (RRs) with 95%
confidence intervals (CIs) as the metric of choice for all the outcomes. The
overall effects were evaluated using Z-statistics,
and the value of P was acquired
according to the value of Z. We
implemented a Meta-analysis of the direct evidence for each outcome by
combining pairwise comparisons between the optic capture and no-optic capture
groups using Review Manager 5.2. Between-study heterogeneity was evaluated by Q-statistics and quantified by the I2 statistic. If statistically
significant heterogeneity was considered to be present (I2>50%), we chose a random-effects model; otherwise,
a fixed effects model was used. Any P-value
less than 0.05 was regarded as statistically significant for all included
studies. To analyze the between-study heterogeneity, we divided the subgroups
or excluded one study at a time until all of the studies had been excluded once
in this manner. To analyze the sensitivity of the Meta-analysis, we excluded
one study at a time until all the studies had been excluded once in this
manner.
RESULTS
Literature
Search and Study Characteristics We
identified 139 potentially relevant studies from the initial search, and 97
studies were excluded after a preliminary review. The remaining 42 studies were
identified for detailed assessment. Finally, 5 RCTs and 5 chart series met the
inclusion criteria. The selection process and reasons for exclusion are
summarized in Figure 1[5-9,11-15].
Figure 1 PRISMA
flow chart of the literature search and study selection.
The baseline characteristics of the participants and
the design of the studies are summarized in Table 1. Tables 2-4 present the
main results from each included study.
Table 1
Characteristics of included studies
Study |
Type/Rank |
Sources |
Database |
Eyes |
Age |
Follow-up |
Kohnen
et al[5] |
Case
control/Ⅲ |
Cullen Eye Institute,
USA |
PubMed |
16 |
1.5-12a |
>6mo |
Gimble[6] |
Case
control/Ⅲ |
Gimbel Eye Centre,
Canada |
PubMed |
13 |
2-12a |
8-28mo |
Vasavada
and Trivedi[7] |
RCT/Ⅱ |
lladevi Cataract
& IOL Research Center, India |
PubMed |
40 |
4-55mo |
5-24mo |
Koch
and Kohnen[8] |
Case
control/Ⅲ |
Cullen Eye Institute,
USA |
PubMed |
20 |
1.5-2a |
1-4.5a |
Müllner-Eidenböck
et al[9] |
RCT/Ⅱ |
University of Vienna,
Austria |
PubMed |
50 |
2-16a |
8-41mo |
Raina
et al[11] |
RCT/Ⅱ |
Guru Nanak Eye
Centre, India |
PubMed |
34 |
1.5-12a |
8-28mo |
Vasavada
and Desai[12] |
Cohort/Ⅲ |
lladevi Cataract
& IOL Research Center, India |
PubMed |
18 |
3mo-5a |
Average
13.3mo |
Raina
et al[13] |
RCT/Ⅱ |
Guru Nanak Eye
Centre, India |
PubMed |
42 |
36-144mo |
6-18mo |
Faramarzi
and Javadi[14] |
RCT/Ⅱ |
Labbafinejad Medical
Center, Iran |
PubMed |
28 |
2.5-8.0a |
13-35mo |
Shiratani
et al[15] |
Case
control/Ⅲ |
Kitasato University,
Japan |
Embase |
21 |
6mo-15a |
1-50mo |
RCT: Randomized controlled trials.
Table 2 Secondary
opacification in each included study when posterior continuous curvilinear capsulorhexis
was noted
|
Anterior vitrectomy group (secondary opacification eyes/total eyes) |
No-anterior vitrectomy group (secondary opacification eyes/total eyes) |
||
Capture |
No capture |
Capture |
No capture |
|
Kohnen
et al[5] |
0/2 |
0/3 |
0/2 |
4/4 |
Gimble[6] |
- |
- |
0/13 |
2/5 |
Vasavada
and Trivedi[7] |
0/14 |
0/26 |
- |
- |
Koch
and Kohnen[8] |
0/3 |
0/3 |
4/5 |
4/4 |
Müllner-Eidenböck
et al[9] |
0/8 |
1/12 |
0/7 |
0/8 |
Raina
et al[11] |
- |
- |
0/16 |
8/18 |
Vasavada
and Desai[12] |
0/5 |
0/5 |
3/3 |
2/5 |
Raina
et al[13] |
- |
0/4 |
0/6 |
0/7 |
Faramarzi
and Javadi[14] |
0/14 |
0/14 |
- |
- |
Shiratani
et al[15] |
- |
- |
0/17 |
0/2 |
-: No
available data.
Table 3 Best
corrected visual acuity before and after surgery as well as available spherical
equivalent after surgery in included randomized controlled trials
Study |
Capture group |
No capture group |
||||
Before
surgery (logMar) |
After
surgery (logMar) |
Spherical
equivalent (D) |
Before
surgery (logMar) |
After
surgery (logMar) |
Spherical
equivalent (D) |
|
1Raina
et al[11] |
- |
0.23±0.15 |
- |
- |
0.21±0.15 |
- |
2Raina et al[13] |
- |
0.19±0.11 |
-0.250 |
- |
0.19± 0.10 |
-0.264 |
Faramarzi
and Javadi[14] |
0.99±0.18 |
0.27±0.14 |
0.75±1.37 |
0.97±0.23 |
0.32±0.14 |
0.82±0.92 |
1The
data for this reference were extracted from their tables and calculated
according to the principles of data processing, and entries labeled CNBA (could
not be assessed) were excluded; 2The data for this reference were from B
group and D group; -: No
available data.
Table 4 Main
complications of the included randomized controlled trials
Study |
Capture (evented eyes/total eyes) |
No capture (evented eyes/total eyes) |
||||
|
Deposits |
Decentration |
Synechia |
Deposits |
Decentration |
|
Vasavada
and Trivedi[7] |
10/14 |
14/14 |
0/14 |
9/26 |
16/26 |
19/26 |
Müllner-Eidenböck
et al[9] |
- |
2/8 |
0/8 |
- |
0/12 |
2/12 |
Raina
et al[11] |
- |
9/16 |
- |
- |
10/18 |
- |
Raina
et al[13] |
0/6 |
5/6 |
- |
1/7 |
4/7 |
- |
Faramarzi
and Javadi[14] |
0/14 |
3/14 |
0/14 |
1/14 |
3/14 |
3/14 |
-: No
available data.
Secondary
Posterior Capsular Opacification Figure
2 presents the forest plot of 5 RCTs involving 150 eyes that assessed the
effect of preventing posterior capsular opacification (PCO) by comparing optic
capture with no-optic capture. A fixed effects model was adopted because the I2 was less than 50%. The
incidence rates of PCO between the two groups were significantly different (RR:
0.12; 95% CI: 0.02 to 0.85; P=0.03) with no evidence of heterogeneity (I2=0%, P=0.36). We
studied 1 cohort and 4 case control studies together with 5 RCTs. The incidence
rates of PCO between the two groups were significantly different (RR: 0.44; 95%
CI: 0.22 to 0.88; P=0.02) with no evidence of heterogeneity (I2=37%, P=0.16). No
significant difference between subgroups was found (I2=63.2%, P=0.10).
Figure 2 Forest
plots for RRs of posterior capsular opacification comparing optic capture to
no-optic capture.
Best Corrected
Visual Acuity Figure 3 illustrates a forest plot of 3
RCTs involving 75 eyes showing the effect of mean BCVA after surgery between
the two groups. Because the outcome of the heterogeneity test was not
significant (I2=0%, P=0.63),
a fixed effects model was adopted. The pooled result indicates that the mean
BCVAs were not significantly different between the two groups (WMD: -0.01; 95%
CI: -0.07 to 0.05; P=0.75). Furthermore, mean BCVAs of patients whose
ages are less than 4 or equal to 4 were not significantly different between the
two groups (t=0.708; P=0.489).
Figure 3 Forest
plot for WMD of mean BCVA comparing optic capture to no-optic capture.
Geometric
Decentration of IOL Figure 4 presents a forest plot of 3 RCTs
involving 88 eyes assessing the effect of preventing geometric decentration
after surgery between the two groups. Because the outcome of the heterogeneity
test was not significant (I2=0%,
P=0.62), a fixed effects model was adopted. The pooled result indicates
that the incidence rates of geometric decentration were significantly different
between the two groups (RR: 0.09; 95% CI: 0.02 to 0.46; P=0.004).
Figure 4 Forest
plot for RR of geometric decentration comparing optic capture to no-optic
capture.
Adverse Events The
main adverse events after pediatric cataracts in the two groups were PCO,
geometric decentration, posterior synechia and deposits on the anterior IOL.
Other rare adverse events include proliferating cells on the posterior
capsulorhexis margin, glistening on the IOL and suture granuloma[14]. The available data
regarding posterior synechia, deposits in the anterior IOL and geometric
decentration in RCTs are presented in Table 4.
We analyzed 3 RCTs involving 81 eyes assessing the
incidence rates of posterior synechia after surgery for the two groups. Because
the outcome of the heterogeneity test was not significant (I2=25%, P=0.27), a fixed effects model was
adopted. The pooled result indicates that the incidence rates of posterior
synechia were not significantly different between the two groups (RR: 1.53; 95%
CI: 0.84 to 2.77; P=0.17).
Figure 5 presents forest plots of 5 RCTs involving
135 eyes assessing the incidence rates of deposits on the anterior IOL surface
early after the surgery and at the last follow-up between the two groups.
Because the outcome of the heterogeneity test was not significant (I2=0%, P=0.53; Figure
5A), a fixed effects model was adopted. The overall results from 5 RCTs
indicate that the incidence rate of deposits in the anterior IOL of the optic
capture group was significantly higher compared with the no-optic capture group
early after the surgery (RR: 1.40; 95% CI: 1.05 to 1.86; P=0.02; Figure
5A). Because the outcome of the heterogeneity test was not significant (I2=0%, P=0.38; Figure
5B), a fixed effects model was adopted. The overall results from 5 RCTs
indicate that the incidence rate of deposits on the anterior IOL in the optic
capture group remained significantly higher compared with the no-optic capture
group at the last follow-up (RR: 2.30; 95% CI: 1.08 to 4.92; P=0.03;
Figure 5B).
Figure 5 Forest
plots for RRs of deposits in anterior IOL comparing optic capture to no-optic
capture A: Deposits in the anterior IOL early
after surgery; B: Deposits in the anterior IOL at the last follow-up.
In response to
anti-inflammation treatments, the deposits on the anterior IOL early after
surgery can gradually disappear[11,13-14].
Among the studies, 2 studies specified the use of steroids[11,13].
Publication Bias To
analyze the publication bias, we created funnel plots. For the available data,
no publication bias existed in any of the previously mentioned Meta-analyses.
Heterogeneity
and Sensitivity Analysis The
Meta-analyses of the effects of optic capture on the incidence rates of PCO,
BCVA after surgery, posterior synechia, geometric decentration and deposits in
the anterior IOL early after surgery and at the last follow-up exhibited no
heterogeneity given that the I2
values in these Meta-analyses were all less than 50%.
A sensitivity analysis for the Meta-analysis of the
effect of optic capture on preventing PCO after surgery was accomplished as
follows. After excluding the study of Raina et
al[11], the outcome
of the Meta-analysis significantly altered. We further studied the data of the
paper. In optic capture group, study has 4 patients operated at ≤4y. Follow-up
of these 4 patients varies from 8 to 14.5mo. In no-optic capture group, 6
patients are ≤4 years old. Follow-up of these 6 patients ranges from 12 to 26mo
and 5/6 required PCO surgery, and the interval between surgery and PCO≥2+ formation
ranges from 6 to 12mo. Thus the two sets of data are consistent, and the
sensitivity could be merely due to the fact that the study[11] accounted for 37.9% of the weight. The outcome of
the sensitivity analysis for the Meta-analysis of the effect of optic capture
on the incidence rate of deposits in anterior IOL early after surgery found
that 2 studies[7,9]
significantly affected the outcome of the Meta-analysis. The outcome of the
sensitivity analysis of the Meta-analysis of the effect of optic capture on the
incidence rate of geometric decentration found that 1 study[7] significantly affected the outcome of the
Meta-analysis. No sensitivity existed in the other Meta-analyses.
Risk of Bias and
Quality Assessment We created a risk of bias table for the 5
included RCTs, and no high risk of bias was found. One study[11] specified that the
postoperative outcome was assessed by a third party doctor. With regard to the
use of random methods, 1 study[11]
employed a random digits table, and 1 study[7]
adopted the envelope method. Furthermore, 4 studies[9,11,13-14] specified that the operator was a single
person. With regard to the method of blinding, we can not get any details.
The quality of evidence from each Meta-analysis was
assessed to be high using GRADE recommended by Word Health Organization.
DISCUSSION
This analysis indicates that the application of
optic capture in pediatric cataract surgery significantly reduced PCO (P=0.02)
and geometric decentration after surgery (P=0.004) but did not significantly
affect BCVA after surgery (P=0.75). The application of optic capture in
pediatric cataract surgery did not significantly affect the incidence rate of
posterior synechia after surgery (P=0.17) and significantly increased
the incidence rates of deposits in the anterior IOL early after surgery (P=0.02)
and at the last follow-up (P=0.03). Though the incidence rate of
deposits in the anterior IOL early after surgery was significantly higher in
the optic capture group compared with the no-optic capture group, the
application of optic capture did not seriously increase the incidence rate (RR:
1.40). And several studies [11,13-14,16]
have indicated that the incidence rate of deposits in the anterior IOL
dramatically decreased at the last follow-up after anti-inflammatory therapy.
In the included studies, the total incidence rates of deposits in the anterior
IOL decreased from 33/58 to 10/58 in the optic capture group and from 33/77 to
7/77 in the no-optic capture group. Based on the available data, this analysis
found that optic capture is a helpful surgical method in preventing PCO and
geometric decentration after pediatric cataract surgery with robust efficacy
and a high degree of safety.
As the
anterior vitrectomy increases the incidence rate of vitreous incarceration in
the wound as well as the risk for retinal detachment[1-2] and CME[3].
Some authors attempted to identify a substitute for anterior vitrectomy. Koch and
Kohnen[8] in a case
control study which was conducted on a small scale and did not adopt random
methods found that anterior vitrectomy was the only effective method for
preventing or delaying secondary cataract formation in infants and children,
but in fact optic capture does not contradict anterior vitrectomy. Optic
capture plus anterior vitrectomy should be a preferable surgical method based
on all the findings. Nowadays IOL with 4 haptics is popular; however, IOL with
4 haptics is not suitable for pediatric surgery in certain situations. For
example, a C-loop IOL may serve as a better choice than an IOL with 4 haptics
in a capsular which is too small or is partly fibrotic. Optic capture is
especially suitable for C-loop IOL, thus optic capture is helpful in the
aforementioned situation. Some special IOLs, for example the bag-in-the-lens
which contains a circular concavity on its edge that permits the margins of the
posterior capsular hole to be embedded in it, can facilitate the application of
optic capture[4]. In
addition, optic capture is the method of choice in cases of tear formation in
anterior continuous curvilinear capsularhexis (ACCC)[17]. Optic capture is easy to perform,
as many authors have shown.
Optic capture of the IOL through the PCCC hole
provides a complete fusion of the anterior capsule leaflets, posterior capsule
leaflets and the IOL surface. Thus, the capsular space is closed, and the
migration of LEC to the center of visual axis is more difficult. The pediatric
capsular space is smaller than the adult eye. Implantation of an adult-sized
IOL in an infant capsular bag causes ovalization of the PCCC hole and stretches
the capsular bag[18].
These effects result in posterior capsule folds and striae. The LEC can migrate
toward the center through the capsular folds, leading to PCO. Optic capture
closes the capsular space, thereby preventing capsule stretching and PCO.
Faramarzi and Javadi[14]
found that the incidence rate of geometric decentration in the optic capture
group was less than that in the no-optic capture group, although the difference
was not significant. Vasavada and Trivedi[7]
and Müllner-Eidenböck et al[9] reported similar
findings. These 3 RCTs are small in scale but were well designed. A
Meta-analysis of these 3 RCTs leads to the clear conclusion that optic capture
significantly reduces the incidence rate of geometric decentration. Continuous
capsular margins lock the IOL optic and potentially prevent it from
decentering, whereas in-the-bag implantation may cause IOL decentration given
asymmetric contraction of the capsular space[17]. Optic capture could prevent asymmetric
contraction, thus preventing the IOL optic from decentering. Although Vasavada and
Trivedi[7] reported that
posterior synechia formation was significantly increased in the optic capture
group, 2 additional RCTs[13-14]
found that the posterior synechia was reduced in the optic capture group
compared with the no-optic capture group. This study found that the incidence
rate of posterior synechia was reduced in the optic capture group compared with
the no-optic capture group; however, the difference was not significant. Thus,
whether optic capture increases or decreases the incidence rate of posterior
synechia remains controversial. On one hand, optic capture alters the
anatomical structure of the posterior capsule. Thus, optic capture may reduce
the inflammation, thereby increasing the incidence rate of posterior synechia
and deposits on the anterior IOL surface. On the other hand, the optic was
captured through the PCCC hole, and thus, optic capture may reduce chaffing and
rubbing on the posterior surface of the iris. The IOL implantation site may be
another factor that affects the incidence rates of posterior synechia and
deposits in the anterior IOL. When the IOL is placed in the sulcus,
postsurgical inflammation may be more serious than when the IOL is placed in
the bag.
This research only included studies with data
available in English abstract or full text; therefore, some language bias may
exist. As we only aimed to study the effects of the procedure of optic capture,
we did not divide the data into subgroups according to the performance of
anterior vitrectomy. Although no heterogeneity existed on all the
meta-analyses, the included studies have some heterogeneity in terms of study
location, population, basal condition and surgical techniques. Though Doctor of
Statistics solved difficult data problems, relevant data were relatively
complex. A delay between the literature search and publication was inevitable.
Large-scale, multicenter, randomized controlled
clinical trials aimed at studying infants less than 1.5y in age should have
additional effects. Specific IOLs for pediatric cataract should be developed to
work with optic capture. All of these will induce resurgent studies on optic
capture and improve the outcome of pediatric cataract surgery.
ACKNOWLEDGEMENTS
Conflicts of
Interest: Zhou
HW, None; Zhou F, None.
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