An arcuate stain on the cornea in a GP wearer may be due to which factor?

An arcuate stain on the cornea in a gas permeable (GP) lens wearer is typically associated with poorly blended secondary curves. When the design of the lens does not have a smooth transition between the primary and secondary curves, it can create a distinct area where the lens does not align properly with the cornea. This misalignment can lead to localized pressure points and reduced tear exchange beneath the lens, resulting in staining of the epithelium shaped like an arc.

The formation of an arcuate stain suggests that there have been repeated points of contact causing localized trauma or irritation, which is characteristic of poor curve blending. By ensuring that the secondary curves of the lens are well-blended, the lens can achieve better alignment with the corneal surface, reducing the likelihood of such staining.

Understanding the importance of lens design and curvature is crucial for fitters to avoid these potential issues and to promote corneal health in GP wearers.