Receiving new prescription eyewear often comes with uncertainty regarding whether the vision correction is correct. Many people feel mild discomfort or visual strangeness, which can lead to anxiety about a potential error in the lenses. This article aims to help individuals discern the difference between the typical, temporary adjustment period and genuine, persistent signs that the prescription may be incorrect.
Normal Adjustment Versus Prescription Error
The human visual system requires a brief period to adapt to any change in lens power or design. When transitioning to new glasses, it is common to experience minor symptoms like slight eye strain, a temporary feeling of mild dizziness, or a little blurriness, particularly in the periphery of the lenses. These effects occur as the brain re-learns how to process the images being refracted through the new lens curvature.
A slight distortion or a temporary misjudgment of depth perception is also considered normal, especially with a significant change in prescription strength or a switch to multifocal lenses like progressives. For most people, this adjustment takes only a few days, typically two to three. However, for first-time wearers or those with a major change in prescription, the period can extend up to two weeks. If symptoms are mild and diminish daily, the eyes and brain are likely adapting successfully.
Definitive Signs the Prescription is Incorrect
Symptoms that persist well beyond the normal two-week adjustment window are strong indicators that an error exists in the prescription or the lens manufacturing. One of the most common red flags is persistent, severe headaches that continue daily after wearing the glasses for extended periods. This pain often stems from the ocular muscles constantly straining to compensate for an incorrect optical focus.
Another serious sign is persistent double vision, known as diplopia, or a constant “swimming” or wavy sensation in the peripheral vision that does not subside. If vision is noticeably clearer when the glasses are removed compared to when they are worn, the prescription is likely too strong or contains a substantial error. Furthermore, if the glasses cause persistent nausea or vertigo, this suggests a significant misalignment of the optical center or a prescription that induces unwanted prismatic effects.
Next Steps When You Suspect an Error
If you experience severe or persistent symptoms beyond the expected adjustment period, the first action should be to contact the eye care provider immediately. You should request a re-examination, or at minimum, ask the optician to verify the lenses against the original prescription. The problem could be a simple manufacturing error where the wrong power was placed in the frame.
It is particularly helpful to confirm that two specific measurements were correctly applied to the lenses: the pupillary distance (PD) and the optical center. The PD, measured in millimeters between the centers of your pupils, determines where the optical center of the lens should be placed. If the optical center is misaligned with the pupil, even a correct prescription power will cause visual distortion, eye strain, and headaches.
An incorrect PD causes the wearer to look through a sub-optimal portion of the lens, which is especially noticeable with stronger prescriptions or multifocal designs. Most optical labs and providers offer a free remake or adjustment policy, typically ranging from 30 to 90 days, to address these issues.