Axis uses a circular orientation convention represented on a 180-degree scale. Geometrically the boundary at 0 and 180 describes the same meridian, yet order systems and laboratory workflows may require a specific written range. That distinction explains the form error …
The exception is a checkout that asks for progressive fitting height when the shopper has only a prescription and has not been measured in the selected, adjusted frame. Ordinary data entry cannot safely resolve that gap. Fitting height is not …
“Unreadable” should be converted into a precise defect report. Name the eye, column, and uncertain character—for example, “the sign before OS cylinder is hidden by the ruled line.” That gives the prescriber a question that can be answered without asking …
ADD is not a universal requirement on every glasses prescription. It is associated with a near addition used in multifocal or certain task-specific designs. A distance single-vision order may have no ADD at all, while a progressive order generally cannot …
Plano is meaningful because it records an intentional zero-power state in a particular field. A blank cell, by contrast, may mean unused, not applicable, omitted, or simply cropped from the image. Treating blank and plano as synonyms can create data …
DS is useful only in context. It commonly signals a spherical-power entry without a separate cylinder component, but handwriting, clinic conventions, and checkout design can vary. The abbreviation should remain beside its sphere value and eye row until the seller …
The exception is a checkout labeled only “PD” when the source record contains both near and distance values, or a source number whose viewing condition is missing. Do not choose the smaller value because near PD is often smaller, and …
A fictional source row reads OD SPH −2.25, CYL −0.75, AXIS 090. A checkout menu shows +2.25 directly above −2.25. The digits match, but the values do not. A plus or minus sign is part of the prescription …
Night reflections can come from several surfaces at once: the lens, a smear, the windshield, dashboard light, streetlights, and reflections behind the lens. Before blaming the prescription or buying another coating, reproduce the problem in a controlled order and note …
Single PD and dual PD are two recording formats for pupillary distance, not two competing prescriptions. A single—or binocular—PD is one total value across the pupils. A dual—or monocular—PD records a value for each eye relative to a center reference. …