Certified Paraoptometric (CPO) Practice Exam 2025

What is measured by the term "eyesize"?

1. The overall height of the frame

2. The widest horizontal dimension of the lens opening

3. The distance between the lenses

4. The length of the temples

The correct answer is: The widest horizontal dimension of the lens opening

The term "eyesize" specifically refers to the widest horizontal dimension of the lens opening. This measurement is crucial in optical practice, as it helps determine the size of the lenses that will fit into a particular frame. Understanding eyesize is essential for ensuring that lenses are appropriately sized to match the frames, which affects both the cosmetic appearance and the functional aspects of the eyewear, such as providing optimal vision correction and protection. The other choices, while relevant to overall frame dimensions, do not specifically define the term "eyesize". The overall height of the frame (which relates to how tall the frame is) and the length of the temples (which pertains to how far the glasses extend behind the ears) are important metrics, but they do not align with the definition of eyesize. The distance between the lenses pertains to the spacing of lenses in relation to each other, which again is a different concept compared to the width of the lens opening itself. Therefore, the correct understanding of "eyesize" is as the horizontal measure across the lens area.