In which meridian will a spherical RGP lens touch if fitted to a patient with high oblique astigmatism?

A patient with high oblique astigmatism has a corneal curvature that causes the light to refract differently based on the axis of the astigmatism. In this condition, the steep and flat meridians of the cornea might not align with the standard horizontal and vertical alignment.

When fitting a spherical rigid gas permeable (RGP) lens, the lens is designed to address the refractive errors of the eye. In cases of high oblique astigmatism, the RGP lens typically aligns itself along the axis where the cornea is steep and makes contact primarily in a diagonal meridian. This ensures that the lens can correct the visual acuity by providing a proper refractive surface over the cornea that corresponds effectively with the varying curvatures present.

Touching along the diagonal meridian is crucial, as it accommodates the uneven steepness of the cornea and provides the appropriate correction needed for the patient. This alignment helps maintain adequate lens stability and optimal visual performance, making it the preferable outcome in these cases.