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In order for systematic reviews to make accurate inferences concerning clinical therapy, the primary studies that constitute the review must provide valid results. The Cochrane Handbook for Systematic Reviews states that assessment of validity is an “essential component” of a review that “should influence the analysis, interpretation, and conclusions of the review.” The internal validity of a review’s primary studies must be considered to ensure that bias has not compromised the results, leading to inaccurate estimates of summary effect sizes.   In ophthalmology, there is a need for closer examination of the validity of primary studies comprising a review. As an illustrative example, Gupta Chakrabarti  et al. (2013) compared anti-vascular endothelial growth factor (VEGF) to laser treatment al (2012) discuss emerging ophthalmic treatments  for proliferative and nonproliferative  diabetic retinopathy. commonly referred to as methodological quality, and risk of bias assessment practices in systematic reviews. Many systematic reviews in this specialty do not perform a measure of quality or risk of bias assessment (MQ/ROB), and, oftentimes, those that do continue to include studies with a high risk of bias or low quality. For example, in an article by Gupta et al (2013), In the article,  the author writes states  that anti-VEGF agents consistently receive  the use of anti-vascular endothelial growth factor most interest as possible alternative treatments  forproliferative  diabetic retinopathy is safer than laser treatment. Furthermore, they state retinopathy. The article provides that guidelines set by SIGN and AAO merely mention  that anti-VEGFis becoming the primary  treatment is useful as an adjunct to laser  for diabetic retinopathy. treatment of PDR, however, the Malaysian guidelines indicate that these same agents were to be considered in combination with intraocular steroids and vitrectomy. Most extensively, the NHMRC guidelines recommend anit-VEGF as an adjunct to laser and prior to vitrectomy (2012).  Eldaly et al (2014) conducted a systematic review of this anti-VEGF treatment for diabetic retinopathy. In this review, 18 randomized controlled trials were included in the final assessment. Of these 18 RCTs, seven were at high risk of bias while the rest were unclear in one or more domains (2014). The author goes on to conclude that, “there as very low or low quality evidence from RCTs for the efficacy and safety of anti-VEGF agents when used to treat PDR over and above current standard treatments. However, the results suggest that anti-VEGFs can reduce the risk of intraocular bleeding in people with PDR.” Validity and quality have been very heavily researched areas, particularly in recent years. Validity has been described as the ability of the instrument to measure what it is believed it is measuring (Moher 1995). Researchers have used many different methods to attempt to evaluate the validity and quality of primary studies. Initially, checklists and scales were developed to evaluate whether particular quality items, such as randomization, blinding, allocation concealment, etc., were addressed in the study. Although these are effective at evaluating specific components of study validity, they are often denounced for falsely elevating quality scores. Many of these scales and checklists include items that have no bearing on a study’s actual quality, such as whether there was informed consent or whether there was ethical approval (1995). Furthermore, it was suggested that the choice of scale or checklist could alter the results of systematic reviews (Jüni 1999), and because of this, two main tools emerged as the most accurate: the Jadad scale (Jadad 1996) and the Downs and Black checklist (Downs 1998). Reporting guidelines developed by the predominant review board at this time, QUORUM, necessitated the evaluation of methodological quality of the primary studies in systematic reviews. The Cochrane Collaboration decided there was a need for a new tool, and in 2008 it developed the Cochrane Risk of Bias Tool. Its development was based on a combination of empirical and theoretical considerations, leading to a focus on risk of bias rather than study 'quality' and a division of assessments into six bias domains (Stern 2013). The risk of bias was then ranked as low, high, or unclear with no score calculation. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), which provides the updated reporting guidelines, now calls for the evaluation of bias in all systematic reviews (Moher 2009).   There have only been a small number of meta-epidemiological studies evaluating risk of bias and quality. One group of researchers performed a cross sectional review of risk of bias assessments, and found that most systematic reviews conducted a risk of bias assessment (Hopewell 2013). However, their review was restricted to studies from the Cochrane Database and non-Cochrane reviews from the Database of Abstracts of Reviews of Effects (DARE). Both of these sources are renowned for high methodological quality, and because of this, their results may not be an accurate reflection of primary studies as a whole. Therefore, another group conducted a study that examined how often the risk of bias and quality was assessed in systematic reviews published in the Cochrane Library and in top rated medical journals (Katikireddi 2015). In their study, 59 systematic reviews were examined and only 6 (90\%) of these did not conduct a quality assessment. Nearly half of the reviews they examined reported risk of bias in an obscure manner that did not allow readers to determine which studies included in a review were most robust. Of the 59 reviews examined, 20 did not include their assessment in their analysis. Again, this study examined reviews from high-quality journals across many areas of health research, therefore, article selection was not random, and this may have skewed the results. In another study performed by Johnson et al. (2015), 200 meta-analyses in health promotions from domains in HIV prevention, mental health, and exercise and blood pressure were examined (Johnson 2015). They concluded that quality assessments were conducted frequently, and were often presented as scales. Again, however, the quality assessment results were only occasionally present in the analyses.  As previous studies have shown, quality and risk of bias assessments are often conducted in high-quality systematic reviews. Yet, there are still many unanswered questions on how systematic reviews in clinical specialties appraise quality and risk of bias. We specifically investigated ophthalmology journals to examine the degree to which quality and risk of bias assessments are conducted. We then explored what method was used in their evaluation, what quality components made up these assessments, and how each systematic review integrated primary studies with low quality and high risk of bias into their results.  
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