Looking into clinical studies ‐ Pros and cons of vascular involvemnt in glaucoma

Purpose To assess the strength of the evidence for ocular blood flow involvement in glaucoma. Methods Because of lack of a large number of randomized trials, the assessment of the question must rely on case series and observational studies, and on the replicability of these studies. Results Currently, evidence that measurement of blood flow can diagnose glaucoma or detect progression of glaucomatous disease is lacking, but several aspects are considered consensual, including low blood pressure association with preponderance and progression of POAG, altered OBF parameters, increased variability of OBF, and insufficient vascular autoregulatory response in glaucoma. It is unclear how much these features are independent from each other. Potential pathogenic keys are endothelial dysregulation and conditions with intermittent hypoxia such a sleep apnea. Conclusion Designing a proper study may still be failing because of the difficulties in defining the pathogenesis and exact nature of OBF alteration in glaucoma. Nevertheless, the cumulative information makes it unlikely that blood flow has no role in glaucoma. Although evidence that measurement of blood flow supports a specific treatment recommendation for patients with glaucoma is lacking, it is of interest that some antiglaucoma drugs have a potential to protect blood flow in ocular tissues relating to glaucoma, while the effect of surgery remains unclear.