A meta-analysis on the clinical efficacy and safety of optic capture in pediatric cataract surgery

Methodological quality of the review: Medium confidence

Author: Zhou HW, Zhou F.

Region: United States of America (USA), Canada, India, Austria, Iran and Japan.

Sector: Cataract

Type of cataract: Pediatric cataract

Sub-sector: Surgery

Equity focus: None specified

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background:

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. The accuracy of optic capture after surgery 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.

Research objectives:

To evaluate the clinical efficacy and safety of optic capture in pediatric surgery.

Main findings:

Authors included a total of five randomized-controlled trails and five cohort studies in the review. Of the 10 included studies, four were conducted in India, two were conducted in the USA and one each were conducted in Canada, Iran and Japan. Authors reported attributing low risk of bias of included RCTs.

Authors meta-analysis showed that the application of optic capture significantly reduced both opacification of the visual axis (RR: 0.12; 95% Confidence Interval (CI): 0.02 to 0.85; =0.03) and occurrence of geometric decentration (RR: 0.09; 95% CI: 0.02 to 0.46; =0.004). However, authors note that it did not significantly affect best corrected visual acuity (BCVA) (WMD: -0.01; 95% CI: -0.07 to 0.05; =0.75) and influence the occurrence of posterior synechia (RR: 1.53; 95% CI: 0.84 to 2.77; =0.17). Authors reported that 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; =0.02) and at the last follow-up (RR: 2.30; 95% CI: 1.08 to 4.92; =0.03).

Authors reported that after removing one study from the meta-analysis, the outcome changed significantly.

Based on these findings, authors concluded that “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”

Methodology:

Inclusion criteria consisted of 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.

Authors conducted a search on the following databases: 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”.

Two authors independently extracted data of included studies and conducted the quality assessment of each study using GRADE. To evaluate the efficacy and safety between the optic capture and no-optic group for the treatment of pediatric cataract, authors assessed the overall effect from the data of included studies and used the pooled weighted mean differences and risk ratios with 95% confidence intervals as the metric of choice for all the outcomes. Between studies heterogeneity was evaluated by Q-statistics and quantified by the I2 statistic. In addition, authors assessed in between-study heterogeneity by dividing studies in sub-groups or excluding one study at a time. Authors also conducted a sensitivity analysis by excluding one study at a time.

Applicability/external validity:

Authors did not discuss the generalizability of the results.

Geographic focus:

Although authors included studies from low- and middle- income settings, they did not discuss the applicability of the results.

Quality assessment:

Overall, there is medium confidence in the conclusions of this study as important limitations were identified. Authors did not conduct a thorough search of the literature to ensure that all relevant studies were included in the review. In addition, authors did not search for unpublished studies and did not review references of included studies as part of the search strategy. It is also not clear if authors avoided selection bias within the review.