If we don't change direction soon, we'll end up where we're going: a description of the SSY Engine.

Data presented during the first two decades of this millennium has shed valuable light on how the intraocular pressure (IOP) is linked to glaucomatous progression. Large prospective controlled trials have confirmed that there is a correlation between the change in intraocular pressure (IOP) and the risk for visual field progression. The magnitude of the effect, as indicated by these studies, is a 10-15% decrease in risk for a 1 mmHg drop in IOP. The risk is correlated with the rate at which patients develops field loss, that is the Rate of Progression or RoP, which in turn makes future projections of a patient's progression over time at a given IOP level a reasonable possibility. This led to the creation of the SSY (Save Sight Years) concept and later the SSY engine, which is a practical application of this model in the form of a web application. This article describes the thinking behind this system, how it works, the caveats and where we think it can benefit clinical practice.