An eye prescription details the lens power required to correct a refractive error, such as nearsightedness, farsightedness, or astigmatism. It specifies the exact strength, axis, and sometimes the prism needed to focus light correctly onto the retina. While modern optometry uses advanced technology, errors can still occur during the examination, transcription, or manufacturing of the lenses. When glasses do not match the eyes’ needs, the result is discomfort and suboptimal vision, suggesting the prescription is incorrect.
Symptoms Indicating a Mismatch
A mismatch between your eyes and new lenses often manifests through physical and visual disturbances. Persistent headaches, frequently localized to the frontal or temporal regions, are a common sign indicating eye muscles are straining to compensate. The eyes may also feel tired or strained, especially after short periods of reading or computer use, as they attempt to focus through the wrong lens power.
Visual signs extend beyond simple blurriness and can involve profound distortions of the visual field. You may experience a phenomenon known as the “fishbowl effect,” where straight lines appear curved or the edges of your vision seem bent or warped. This distortion is particularly noticeable when the prescription for astigmatism (CYL and Axis values) is significantly off or when the lens centers (pupillary distance) are misaligned.
An incorrect prescription can interfere with the brain’s ability to process spatial information, leading to difficulty with depth perception. This can cause objects to appear closer or farther away than they truly are, which may induce dizziness, unsteadiness, or slight nausea. Double vision or increased light sensitivity also suggest the prescribed lens power is either too strong or too weak.
Distinguishing Error from Adaptation
Prescription errors must be distinguished from the normal, temporary adjustment period that accompanies new eyewear. When wearing new glasses, the brain must adapt to the altered visual input, especially if the prescription change was significant or if you switched to progressive lenses. This adaptation process typically causes mild, temporary symptoms like slight eye fatigue, minor distortion, or occasional headaches.
The adjustment period resolves within a few days, though it can extend up to two weeks, especially with a first pair of glasses or a major prescription change. Wear the new glasses consistently during this time to allow the visual system to acclimate. If the discomfort is severe, involves worsening vision, or includes intense nausea or debilitating headaches, the issue is likely an error rather than simple adjustment.
Symptoms that persist beyond the two-week mark or actively intensify over time indicate an error. Normal adaptation symptoms lessen with consistent wear, but an incorrect lens power continues to force the eyes to strain, preventing the brain from accepting the new visual input. This enduring, uncomfortable vision suggests a problem with the prescribed power, astigmatism correction, or physical parameters like optical center placement.
Resolving the Prescription Issue
Contact the prescribing optometrist or ophthalmologist immediately. Do not attempt to self-diagnose or wait, as prolonged wear of incorrect lenses causes unnecessary strain. The eye care professional will schedule a follow-up visit to re-evaluate your vision and examine the glasses themselves.
During this re-examination, the doctor will re-check your visual acuity and perform a second refraction test to confirm the necessary power. They will also use a lensometer to verify the finished lenses, ensuring the power, cylinder, and axis values match the written prescription. Errors can occur in the optical lab if the lenses were incorrectly ground or improperly mounted in the frame.
If the prescription is incorrect or the physical lens parameters are wrong, the doctor will issue an amended prescription or recommend a lens remake. Most reputable optical providers offer a warranty or guarantee, often covering one prescription change or lens remake within a defined period, typically 30 to 90 days. Working directly with the original prescriber and dispenser streamlines this process, ensuring all parties are aligned on the required correction.