Astigmatism is a common condition where the eye’s front surface is shaped more like a rugby ball than a perfectly round sphere, causing light to focus unevenly and resulting in blurred or distorted vision. Toric contact lenses are specifically designed to correct this irregularity by having different focusing powers along two perpendicular axes. For these lenses to work, they must maintain a precise orientation on the eye. Blurry vision is often a sign that something is disrupting this delicate balance, but this fluctuation in clarity is usually fixable.
Lens Orientation and Rotational Stability
The most frequent cause of fluctuating blurriness with toric lenses is rotational instability. Unlike standard contact lenses, a toric lens has a weighted design, often called ballasting, which ensures the lens settles and remains in the correct axial position on the eye. If the lens rotates out of this intended position, even by a small amount, the vision correction is misaligned, immediately causing blur.
The precise fit of the lens on the cornea is a major factor in maintaining this stability. If the lens’s base curve is too flat, the lens may move excessively or rotate too freely with every blink, leading to variable clarity. Conversely, a base curve that is too steep can cause the lens to fit too tightly, locking it into an incorrect, constantly blurred position. The lens may also slip if the material or stabilization design is incompatible with the individual’s eyelid anatomy or blinking pattern.
Another common user-related issue is inserting the lens inside-out, which prevents the weighted design from functioning correctly. Swapping the right and left lenses, if they have different prescriptions, will also result in significant blurriness. These factors disrupt the necessary alignment, transforming the lens from a vision corrector into a source of distortion.
Surface Quality and Lens Damage
Blurry vision can also stem from issues directly on the lens surface, affecting its optical clarity. Lenses naturally accumulate deposits from the tear film, including proteins, lipids, and calcium. If the lenses are not cleaned properly or are worn past their replacement schedule, this buildup can cloud vision.
Dryness is another common culprit, as the lens material can become dehydrated, particularly after prolonged screen use or in low-humidity environments. When the lens loses hydration, its shape can distort slightly, reducing visual quality and often exaggerating rotational movement. Physical damage, such as a microscopic tear or scratch caused by improper handling, can also interfere with the path of light, resulting in persistent blur.
Changes in Eye Health or Prescription
Sometimes, the blurriness is not a problem with the lens itself, but rather a change in the eye’s underlying physiology. The astigmatism’s power and precise axial location, on which the original toric prescription is based, can change over time. A shift in the astigmatism axis, even a minor one, can render the current lens ineffective since its corrective cylinder is no longer aligned with the eye’s need.
The overall refractive error may also progress, meaning the eye’s nearsightedness or farsightedness component requires an updated power. Furthermore, the development of other ocular conditions can introduce blur that the toric lens is not designed to correct. Conditions like cataracts or the onset of ocular surface disease, such as severe dry eye, can compromise visual clarity regardless of the contact lens correction.
When to Consult Your Eye Doctor
If vision remains blurry despite cleaning the lenses thoroughly and ensuring they are inserted correctly, professional assessment is necessary. Persistent blurriness after blinking, noticeable discomfort, pain, or redness are clear signals to schedule an appointment. Only an eye care professional can properly evaluate the exact rotational position of the lens on the eye using specialized equipment.
The doctor can determine if the lens is rotating due to an improper base curve fit or if a slight adjustment to the cylinder axis is required. They will also perform a comprehensive examination to rule out underlying physiological changes, such as a prescription change or the development of a new eye health condition. This assessment ensures the root cause is identified and properly addressed, whether it requires a change in lens brand, fit, or prescription.