American Board of Ophthalmology (ABO) Practice Exam

What are the lighted lines that become focused in a lensometer called?

1. Beams

2. Flares

3. Mires

4. Lines

The correct answer is: Mires

The lighted lines that become focused in a lensometer are referred to as mires. In the context of lensometry, mires are the distinct lines or patterns that are viewed through the instrument when the lens is being evaluated. These mires assist in determining the optical properties of the lens, such as its power and any astigmatism present. When the mires are clearly focused, it indicates that the lensometer is correctly aligned with the lens being tested. The distinct appearance of these lighted lines allows for precise measurements to be taken. This clarity is crucial for the accurate interpretation of optical prescriptions and for ensuring optimal vision correction for patients. Options like beams and flares do not have a specific definition within the context of lensometry, while lines could refer to various markings or indicators but do not accurately describe the specific function and significance of mires in the lensometer's operation. Thus, mires is the precise term that captures the essence of what is viewed and measured within a lensometer.