In the medical context refers to the total financial impact that a disease or health condition imposes on individuals, households, healthcare systems, and society. This burden is typically divided into direct costs (such as expenditures for medical care, hospitalizations, medications, diagnostic tests, and preventive actions) and indirect costs (including lost productivity, absenteeism, presenteeism, loss of income, and premature death).

The ability of an intervention to produce the intended effect under controlled study conditions.

A predefined variable or outcome used to evaluate the effect, safety, or other impact of a treatment or intervention. For example, the primary efficacy endpoint in PROSPER is the change from baseline to Week 52 on the PSP Rating Scale (PSPRS).

Refers to heritable changes that do not affect the DNA sequence but influence gene expression (e.g., chemical modifications).

Located or occurring outside the cell.

Inability to voluntarily open the eyelids after they have been closed for a period of time.