Seeing ADD different in each eye on a prescription should trigger verification, not automatic correction. Unequal additions can be intentionally prescribed, but they can also result from comparing different dates, reading the wrong row, losing an OD/OS label, or mistaking a complete near sphere for an ADD. The order must preserve what the prescriber issued while making sure both numbers belong to the same instruction.
Unequal ADD values are possible, but they are not a casual edit
ADD represents additional plus power used for a nearer viewing range in a multifocal or related design. Many prescriptions show the same addition for both eyes, which can make an unequal pair look suspicious. Frequency is not a validity test. A prescriber may intentionally write different values based on the patient’s visual system and task.
Do not average the values, copy the higher or lower number to both eyes, or choose the only value accepted by a form. Each action replaces a documented instruction with a customer-created one. Even a small numerical change can alter how the near portion is produced or how a finished pair is evaluated.
The correct first statement is limited: “The document appears to show unequal ADD values.” The issuing office or reviewing optical lab must determine whether that appearance is intentional and orderable.
Make sure the values belong to the same exam and row
Mixed records are a common source of false differences. A portal can display an old distance prescription beside a newer reading prescription. A PDF may put contact-lens and spectacle data on adjacent pages. A handwritten note may list an occupational add separately from a general near add.
Reconstruct the source before comparing numbers:
- confirm patient name and examination date on every page;
- identify OD and OS rather than assuming top and bottom rows;
- locate the column labeled ADD, Near ADD, Reading Add, or an office-specific equivalent;
- check for separate distance, near, computer, or occupational sections;
- verify that a number is not visual acuity, prism, or a fitting measurement;
- retain plus signs and decimal places exactly as issued.
If the source combines multiple dates or purposes, request one current spectacle-prescription document. Do not assemble a “complete” order from the most convenient field on each page.
Check whether the prescription uses a ditto mark or a single ADD centered between the eye rows. That layout can mean the same addition applies to both eyes, but the issuing office should confirm its convention if the scan is unclear. Conversely, two separately written values should not be collapsed merely because a previous document used one shared entry.
Portal formatting can also repeat one value visually while storing two fields. Save the original signed page as the authority and treat the portal view as a secondary transcription unless the practice identifies it as the issued prescription.
Reading, progressive, and occupational orders use ADD differently
An ADD value does not select a finished lens design by itself. A progressive lens uses the prescription and fitting data to distribute distance, intermediate, and near zones. A lined bifocal places a distinct near segment. A dedicated reading pair may instead be written as a complete near prescription. An occupational design may limit its far range to a room or workstation.
That distinction matters because a complete near sphere can already include the near addition. Copying it into SPH and then entering ADD again may apply near power twice. The reading-versus-distance prescription guide explains that document-format problem without expanding this page into a general lens-design comparison.
When requesting clarification, name the planned lens use. “Is this unequal ADD intentional for a progressive order?” is more precise than “Which number is right?” The answer may depend on whether the prescription was written for full-time multifocals, a near-only pair, or a defined occupational distance.
Order forms that accept only one ADD need human review
A form that presents one shared ADD field has made a workflow assumption. It has not invalidated the prescription. Do not force unequal values into that interface by choosing one, averaging them, or writing a second value in an unrelated notes box without confirmation.
Send the complete document to optical support and ask four operational questions:
- Can the selected lens design be produced with separate OD and OS ADD values?
- Where should each value be recorded so it reaches the lab as structured data?
- Does the selected frame meet the design’s fitting and minimum-height requirements?
- Will the confirmation display both additions before production approval?
If the retailer or lab cannot support the exact instruction, stop. A different order route, lens design, or provider may be required. Selecting a frame does not justify simplifying the prescription.
Preserve the original notation when asking for confirmation
Use a request that carries the ambiguity and the source together:
“The current spectacle prescription dated [date] shows ADD [value] for OD and [value] for OS. Please confirm whether the unequal additions are intentional for [planned lens type/task] and provide the correct order-entry format.”
Do not ask the support agent to diagnose why the values differ. The practical objective is faithful manufacturing and a traceable record. Save the response with the prescription and compare the final order summary eye by eye.
Recheck the delivered order without self-adjusting power
When the glasses arrive, confirm that the paperwork still shows the intended OD and OS additions and that the frame sits at the fitted height. Evaluate the pair only for the prescribed task and follow the dispenser’s adaptation guidance. A stable frame that slides later can change access to multifocal zones even when the powers were manufactured correctly.
Report a problem with observable details: which eye or viewing direction seems affected, the target distance, how long the pair was worn, whether clarity changes when the frame is repositioned, and whether symptoms persist. Do not “test” a lower or averaged ADD by ordering another pair. The prescriber and lab need the original values, measurements, and delivered-lens verification to separate power, fitting, and design issues.
The Manlykicks prescription-entry guide can help identify standard fields, while order-specific limitations belong with the Help Center. Explore prescription glasses only after support confirms that the selected lens route can preserve both additions.
Unequal ADD values deserve attention precisely because they may be legitimate. Verification protects an intentional asymmetry from being “corrected” into the wrong order.