Certified Paraoptometric (CPO) Practice Exam 2025

Which type of lens generally provides sharper vision?

1. Soft

2. Rigid

3. Fitted

4. Orthokeratology

The correct answer is: Rigid

Rigid lenses, also known as Rigid Gas Permeable (RGP) lenses, are known for providing sharper vision compared to soft lenses. This is largely due to their ability to maintain their shape on the eye, which allows for more precise focusing and better correction of refractive errors. The rigid material creates a smoother surface that can enhance visual clarity, particularly for individuals with astigmatism. In contrast, soft lenses are typically more flexible and can mold to the shape of the eye, which may slightly compromise the optical quality compared to rigid lenses. Fitted lenses and orthokeratology lenses serve specific purposes but do not necessarily provide the general sharpness of vision that rigid lenses do. Fitted lenses could refer to a range of options that aren't specified, while orthokeratology is a method that temporarily reshapes the cornea overnight, primarily for daytime vision correction, and its effectiveness can vary individually. Thus, the choice of rigid lenses is the best option for generally sharper vision.