The Sighting Center

Positions of the horizontal and vertical centre of rotation in eyes with different refractive errors

“…As refractive errors are primarily determined by axial length, 15 it is reasonable to assume that the COR position may change with refractive error. It was also reported that the COR varies linearly with refractive error by 0.166 mm/D, 3 or alternatively 0.14 and 0.18 mm for the horizontal and vertical COR, respectively 2 …”

“…Eye movements can be divided into gaze‐stabilising and gaze‐shifting movements 1 . All movements or rotations of the eyeball are performed around a centre of rotation (COR) that is located inside the globe, behind the posterior pole of the lens and close to the posterior nodal distance 2 . Since the globe is not perfectly spherical, the exact location of the COR is somewhat controversial.…”

“…3 Empirical studies suggested that the COR, on average, is located 13-15 mm behind the corneal vertex of the eye. [2][3][4] Because the emmetropic eye is assumed to be close to spherical, the COR during eye movements should coincide with the centre of curvature of the posterior globe. 5 However, when eye shape and axial length change due to the presence of axial refractive errors, this may change.…”

Sphero‐cylindrical error for oblique gaze as a function of the position of the centre of rotation of the eye

“…In Figure it can be seen that both spheres are centred on the CRE. As a consequence, our model for dynamic vision assumes that the visual axis is always passing through the CRE and that the CRE position corresponds with the position usually measured in the clinical environment, the sighting centre position…”

Spectacle Lens Design – Development and Present State

“…The main disadvantage of high index lenses is their low constringence (V = [30][31][32][33][34][35][36][37][38][39][40]. For a given lens power, transverse chromatic aberration is much greater with high index glass lenses than with ophthalmic crown and CR39 lenses.…”