Methods

We conducted a PubMed search of MEDLINE for systematic reviews and/or meta-analyses published in the American Journal of Ophthalmology, British Journal of Ophthalmology, Investigative Ophthalmology and Visual Science, The Journal of the American Medical Association- Ophthalmology, Ocular Surface, Ophthalmology, and Progress in Retinal and Eye Research from 2005 to 2015. We used the following search string: (((((((((“Progress in retinal and eye research”[Journal])) OR “Archives of ophthalmology”[Journal]) OR “Ophthalmology”[Journal]) OR “The ocular surface”[Journal]) OR “American journal of ophthalmology”[Journal])) OR “Investigative ophthalmology & visual science”[Journal])) OR “The British journal of ophthalmology”[Journal]AND ((((meta-analysis[Title/Abstract]) OR meta-analysis[MeSH Terms]) OR systematic review[Title/Abstract]) OR systematic review[MeSH Terms]) OR meta-analysis[Publication Type]. This search strategy was a modification of Montori et al., \cite{Montori_2005} which has shown to be sensitive to identifying systematic reviews and meta-analyses. The search was conducted on January 30, 2015. Prior to screen and data abstraction, an abstraction manual was developed to standardize coding practices. This manual was pilot tested using a subset of 25 systematic reviews. Revisions were made as necessary. Following the pilot test, we held a training session for coders based on the manual using a subset of 5 systematic reviews. Results were discussed between coders and any discrepancies were resolved by consensus. Rater agreement was also calculated on a randomly selected subset of 10 systematic reviews and found to be 99.09%. After training, all full-text articles were retrieved and screened during the coding process. The types of excluded articles are detailed in Figure 1. We coded the following elements: (a) name of first author; (b) year of publication; (c) name of journal; (d) whether author addressed quality/risk of bias; (e) what tool was used for quality/risk of bias assessment; (f) whether author used custom measures for quality/risk of bias assessment; (g) whether primary articles in review were graded; (f) what scale was used for grading; (h) whether quality/risk of bias was found; (i) whether quality/risk of bias was included in review; (j) whether a follow up analysis was conducted (subgroup, meta-regression, sensitivity analysis).