  The shear triplet statistics is a geometric method to measure cosmological
parameters with observations in the weak gravitational lensing regime towards
massive haloes. Here, this proposal is considered to probe the dark energy
equation of state and its time derivative in view of future wide-field galaxy
surveys. A survey with a median redshift of nearly 0.7 and a total area of
nearly 10000 square degrees would be pretty effective in determining the dark
matter cosmological density and in putting useful constraints on the dark
energy properties.
