Final answer:
The claim that near Pupillary Distance (PD) measurement utilizes only one side of the pupils or limbus is false. Accurate PD measurements require using both the right and left sides for the most precise fitting of eyewear, which is significant for visual comfort and efficacy. PD is related to ensuring that corrective lenses align properly with the visual axis of each eye.
Step-by-step explanation:
The statement that when taking a near Pupillary Distance (PD) you use only the right or only the left edges of the pupils or limbus as reference points is false. When measuring near PD, both the right and the left edges of the pupils or limbus are important reference points. The reason for this is that PD measurements need to accurately reflect the distance between the centers of the pupils when the eyes are focused on a close object, a position which is generally closer together than when the eyes are looking at a distance. To ensure preciseness in fitting for eyeglasses, especially for near tasks such as reading, a correct measurement of PD is crucial. This accuracy in measurement is significant as it can influence visual comfort and efficacy of the eyewear.
To address the unrelated physics questions, when the limit to the eye's acuity is mentioned, it refers to the fact that our eye's ability to distinguish two separate points as distinct is limited by the diffraction of light through the pupil. When light passes through a small opening like the pupil, it tends to spread, which can cause points of light that are very close together to blur into a single spot. Moreover, the action potentials generated through the Edinger-Westphal nuclei affecting pupil constriction are relevant to describe the complicated neural mechanisms involved in the pupillary reflexes, both direct and consensual, which are part of the eye's response to light exposure.
The discussion about lenses is related to the optics principle that converging lenses focus light, creating a real, inverted image at the focal point, whereas diverging lenses cause light rays to spread out. The bright spot that can burn a paper when using a converging lens under sunlight is indeed a focused image of the sun.