I was reading this abstract and trying to conceptualize the curvature measurement.
They list the discrimination threshold at $~0.59/m$ -- Is this $degrees/meter$? Would that make the circumference $360^{\circ}/0.59$ meters? and then the diameter $(360^{\circ}/0.59)/\pi$?
The curvature of a circle is the inverse of the radius, so it has units of inverse length. A curvature of $0.59 \text{ m}^{-1}$ (which is how I would write it) corresponds to a radius of $\frac 1{0.59}$ meter.