Many people wonder if their glasses prescription might be too strong, causing discomfort or visual disturbances. This article provides general information on signs of an overly strong prescription and what steps to consider, but it is not a substitute for professional medical advice.
Understanding Prescription Strength
A glasses prescription measures the optical power needed to correct refractive errors, in units called diopters. These numbers show how much a lens must bend light to focus it onto the retina. A negative sign (-) indicates nearsightedness (myopia), where distant objects appear blurry. A positive sign (+) indicates farsightedness (hyperopia), causing near objects to be out of focus.
A “too strong” prescription means the lenses provide more correction than the eyes require. For nearsightedness, this involves a negative number that is too high, causing light to converge too sharply. For farsightedness, an excessively high positive number would overcorrect the eye’s natural focusing ability. This overcorrection makes the visual system work harder, leading to discomfort.
Recognizing the Signs
Persistent blurry vision, especially when focusing on objects at various distances, is a primary indicator of an overly strong prescription. The lenses refract light in a way that prevents a clear image from forming on the retina. The eyes might struggle to find a comfortable focal point, making objects appear fuzzy or lacking sharp edges.
Headaches and eye strain are also common symptoms. When eyes continuously over-compensate for an incorrect prescription, the surrounding muscles can become fatigued. This leads to tension headaches, often felt around the temples or behind the eyes. This strain is particularly noticeable during prolonged visual tasks like reading or using digital screens.
An incorrect prescription can also cause dizziness, nausea, or disorientation. The altered way light enters the eyes can affect spatial awareness and balance, sometimes causing motion sickness or feeling off-balance. Individuals might also experience difficulty with depth perception, misjudging distances, or feeling unsteady while walking.
Common Reasons for an Incorrect Prescription
Several factors can contribute to a glasses prescription feeling too strong. Vision naturally changes over time due to refractive errors like myopia or presbyopia (age-related loss of near focusing ability). An updated prescription might feel different simply because it reflects these changes, and eyes require an adjustment period.
In some instances, the initial eye examination measurement might have been slightly inaccurate. While errors are uncommon, factors like eye fatigue during the exam or minor clerical mistakes can lead to an unsuitable prescription. Additionally, issues during lens fitting, such as an incorrect pupillary distance (PD), can cause discomfort even with an otherwise correct prescription.
Sometimes, the sensation of an overly strong prescription is part of a normal adaptation period to new glasses. This is especially true with a significant change in prescription strength or when transitioning to different lens types, such as progressive lenses. The brain needs time to adjust to the new visual input, and temporary symptoms are expected during this phase.
What to Do Next
If you suspect your glasses prescription is too strong, consult an eye care professional, such as an optometrist or ophthalmologist. It is not advisable to self-diagnose or attempt to “get used to” severe or persistent discomfort. An eye doctor can perform a comprehensive eye exam to assess your vision and determine if your current prescription is causing your symptoms.
When you visit your eye doctor, describe your symptoms in detail, including when they occur and how long they have been present. This information is valuable for the professional to understand the nature of your discomfort. They can then re-evaluate your prescription and, if necessary, make adjustments to ensure optimal vision and comfort.
Regular eye examinations are important for maintaining good eye health and ensuring your prescription remains appropriate for your current vision needs. While an adjustment period of a few days to two weeks is normal for new glasses, persistent issues beyond this timeframe suggest that a re-evaluation is warranted. Your eye care professional can verify the prescription and check for any manufacturing errors or fitting issues that might be contributing to your discomfort.