. 2019 Apr 18;13:649–669. doi: 10.2147/OPTH.S198401
© 2019 Cabahug et al. This work is published and licensed by Dove Medical Press Limited
The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed.
Figure 2.
Risk of bias summary: (+) low risk, (?) unclear risk, (−) high risk.