Final answer:
The total Seg Inset is calculated using the formula: Total Seg Inset = (Frame PD) - (2 x Mono PD). This is used in optometry to determine the correct positioning of lenses in glasses frames for proper optical alignment.
Step-by-step explanation:
The formula to calculate total Seg Inset using Mono PD (monocular pupillary distance) is given by:
Total Seg Inset = (Frame PD) − (2 × Mono PD)
This calculation is commonly used in optometry to determine the proper placement of the optical centers of glasses lenses. The Frame PD is the distance between the centers of the two lenses in a pair of glasses, and the Mono PD is the distance from the center of a single lens to the center of the pupil of one eye. By doubling the Mono PD, we get the combined PD for both eyes and then can determine how much inset (or outset) is needed in the lens placement to achieve proper optical alignment.