Ophthalmic Dispensing Equipment at a Glance
PD Rulers PD Rulers are used to measure the pupillary distance which is the distance, typically taken in millimeters to ensure accuracy, between the centers of the pupils of each eye. This measurement is critical to the proper fitting of prescription eyeglasses. PD Rulers can be made of plastic, wood or metal and many are customized to ensure proper measurement.
Lens Clock The lens clock is another critical measurement tool in the creation of prescription eyeglasses. The lens clock allows an optician, optometrist or ophthalmologist to measure the diopter curve of the spherical lens surface. This ophthalmic instrument has three pins, one of which is spring loaded. This means you can insert the lens and the spring loaded pin can measure the convex and concave sides of a lens which then offers the correct base curve.
Frame Warmers In order for optician, optometrist or ophthalmologist to ensure that your plastic frame glasses properly fit your face, they must sometimes customize the frames and frame warmers are the tools most frequently used for this. The frames are warmed until they can be adjusted to fit properly. There are two main types of frame warmers; Salt Pan and Hot Air. The Salt Pan Frame Warmer, although the more commonly used tool, does not allow for the same precision as the Hot Air Frame Warmer with more specific temperature controls.
PD Meter The PD Meter, or PDM, is used to measure the interpupillary distance, or the distance between the pupils and the left to right pupil to nose distance. This is another critical measurement tool for helping vision healthcare practitioners to create eyeglasses that fit properly.
Pupilometer Pupilometers are used for a number of reasons. A basic pupilometer measures the size of the pupil. For an optician, optometrist or ophthalmologist a corneal pupilometer can actually be used to measure the reaction of the pupil under various lighting conditions. This information is important for evaluating the effect of troublesome glare and halo effects for refractive surgery patients. Newer more sophisticated model even can digitally capture and image of the pupil size for archival purposes.