Effect of transcorneal pressure on small-angle light scattering from rabbit cornea

Small-angle light scattering (SALS) measurements from the central region of the rabbit cornea are presented. These measurements are unique since a transcorneal pressure is applied. The variation of the SALS patterns with pressure suggests that a new explanation of their origin should be considered. I₊ scattering changes markedly with the application of pressure and slight changes are also noted in I_II scattering. At less than 1 mmHg pressure ('zero' pressure), the I₊ pattern is a five-lobed cloverleaf, with one lobe at 0° scattering angle, and the others oriented along the polarization directions with intensity maxima at 1.8° scattering angle. The intensity of this pattern decreases dramatically as the pressure increases and a second cloverleaf pattern, aligned at 45° to the polarization direction becomes apparent. It is suggested that the waviness of the corneal stroma lamellae, noted in electron micrographs of tissue fixed in the absence of pressure, be considered as the morphological feature responsible for the 'zero' pressure pattern. The second cloverleaf pattern may be associated with stromal cells.