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Yoga research citations from 1948 to 2020 in PubMed were filtered and sorted in 10-year intervals to explore the occurrence and time frame of change in (1) the focus of research; (2) the number of randomized controlled trials (RCTs), systematic reviews (SRs), and meta-analyses (MAs); (3) health conditions researched for yoga as therapy; (4) journals with yoga research; and (5) the research on yoga from different countries. Publications on yoga between 1948 and 1970 (1.25%) focused on exceptional abilities of experienced yoga practitioners, apparently related to the spiritual goal of yoga; from 1971 to 2000 (6.87%), the focus was on yoga in health and therapy; and from 2001 to 2020 (91.88%), research publications on yoga increased and continued to focus on health and therapy, with fewer RCTs relative to the SRs and MAs on yoga in PubMed. Publications on yoga reported the following health conditions most often: from 1981 to 1990, (1) asthma, (2) stress, and (3) diabetes; from 1991 to 2000, (1) stress followed by (2) asthma, anxiety, and pain (all three with equal percentages); from 2001 to 2010, (1) depression, (2) stress, and (3) anxiety; and from 2011 to 2020, (1) stress, (2) depression, and (3) pain. The journals publishing research on yoga in PubMed have changed between 1971 and 2020 as follows: highly clinically relevant, broad-interest medical journals (1971 to 1990); journals relevant to mind-body interventions (1991 to 2000); and specialized journals for complementary and alternative medicine, particular branches of medicine, or research study designs (2001 to 2020). The highest yoga research output from 1971 to 1980 came from the United Kingdom (RCTs); from 1981 to 1990 the most research came from the United States (RCTs); from 1991 to 2000 the most research came from India (RCTs) and the United Kingdom (SRs); from 2001 to 2010 the most research came from the United States (RCTs, SRs) and the United Kingdom (MAs); and from 2011 to 2020 the most research came from the United States (RCTs, SRs, MAs). The trends in yoga research from this analysis reflect increased research related to yoga and health while suggesting areas for future research based on the strengths and gaps that have emerged.

Glaucoma is the second leading cause of blindness in the world, with an estimated 57.5 million people suffering from glaucoma globally. Treatment of glaucoma focuses on lowering intra-ocular pressure to prevent progression of visual field defects, which is the only proven method for treating this disease. Yoga practices are believed to lower intra-ocular pressure in the eyes and prevent further damage in patients with glaucoma. Therefore, this systematic review was planned to explore the available scientific studies on yoga and intra-ocular pressure in glaucoma patients. PubMed, Cochrane Library, and Google Scholar were the basis for the investigation of the literature. The Jadad Scale was used to assess the quality of included clinical trials, and the JBI Critical Appraisal Checklist was used to assess the quality of included case studies. Based on the quality assessment and eligibility, six studies on yoga and intra-ocular pressure in glaucoma patients carried out between 2007 and 2021 were included in the final review. The results showed a reduction in intra-ocular pressure in patients with glaucoma through Jyoti-trataka (gazing steadily on a point or candle flame) and some other slow yogic breathing techniques, whereas studies on inversion Asanas (yoga postures) showed a rapid increase in intra-ocular pressure soon after starting. The three high-quality RCTs included in the meta-analysis showed a greater improvement in intra-ocular pressure in the yoga groups in both eyes than in the control groups; however, there were some limitations related to a small sample size, study quality, a long-term follow-up period, and variations in the yoga practices. Therefore, further studies with larger sample sizes and long-term follow-up are needed to overcome the limitations for a better understanding.