The brightness distribution in the blur patch of a point source seen under myopic viewing conditions with a dilated pupil gives an indication of the retinal directional sensitivity (Stiles-Crawford effect). In ten subjects with uncomplicated moderate myopia, approximately one half showed an asymmetrical Stiles-Crawford effect, the foveal receptors pointing towards the nasal edge of the pupil. In the one subject investigated in detail this was combined with an increased myopia in the temporal visual field. This is interpreted as an indication that the back of the eyeball slopes in a nasoposterior direction. These findings may be of significance in progressive myopia.
Westheimer G. Entoptic Visualization of Stiles-Crawford EffectAn Indicator of Eyeball Shape. Arch Ophthalmol. 1968;79(5):584-588. doi:10.1001/archopht.1968.03850040586018