Which measurement is essential for ensuring proper lens fitting?

Pupil Distance (PD) is crucial for achieving a proper lens fitting because it determines the appropriate positioning of the optical centers of the lenses in relation to the wearer's eyes. Accurate measurement of PD ensures that the lenses are aligned with the visual axis, which promotes optimal visual performance and comfort. If the optical centers are misaligned, the wearer may experience various issues such as blurred vision, discomfort, and even eye strain.

While ocular dominance can play a role in visual comfort and function, it does not directly influence the physical fitting of the lenses. Corneal thickness is important for assessing other factors such as the suitability for contact lenses or surgical procedures but is not critical for lens fitting itself. Visual acuity, while necessary for understanding a patient's sight level, does not affect how lenses are positioned or fitted on the face. Thus, PD stands out as the essential measurement for ensuring the precision of lens placement and overall eyewear satisfaction.