For an Rx of +12.50 OU, what is the recommended seg height?

In the context of an Rx of +12.50 diopters for both eyes, the recommended segment height being as high as the wearer will tolerate is based on several important considerations related to the optical and ergonomic needs of a high plus prescription.

For individuals with such a high plus prescription, the optical center of the lenses will be positioned significantly higher than it would be for a lower power lens. Placing the seg height higher ensures that the wearer can comfortably look through the bifocal or multifocal segment without needing to excessively tilt their head or strain their neck. This positioning helps to improve the line of sight through the segment when the wearer is looking downward for tasks such as reading or other close-up activities.

Additionally, a higher segment height can help reduce the distortion that can sometimes occur when looking through the upper portion of a high plus lens. If the segment height were set lower, the wearer might struggle with vision quality and comfort, leading to less effective use of their eyewear.

The other positioning options, such as placing the segment height low or at the lower limbus, do not consider the unique requirements of a high plus prescription and could lead to discomfort or inadequate visual access to the near portion of the lens. Thus, recommending a height that can