What Causes Astigmatism to Worsen?

The cornea and the crystalline lens inside the eye both contribute to astigmatism. As you age, the cornea can gradually shift from a with-the-rule orientation (steeper vertically) to an against-the-rule pattern (steeper horizontally). The internal lens also changes shape over time, which can add to or partially offset corneal astigmatism. These natural shifts explain why many adults notice their astigmatism changing even without any underlying eye disease.

Keratoconus is a progressive condition in which the cornea thins and bulges into a cone-like shape. This structural change causes irregular astigmatism that typically worsens during the teenage years and into the twenties. If your astigmatism is increasing rapidly, especially in one eye, our eye doctors may evaluate you for progressive corneal changes that could indicate keratoconus.

Habitual or vigorous eye rubbing places repetitive mechanical stress on the cornea. Over time, this can weaken the corneal tissue and accelerate thinning, contributing to worsening astigmatism. This risk factor is especially significant in patients who already have early keratoconus or a genetic predisposition to corneal thinning.

Previous eye surgeries, including cataract removal, corneal transplantation, or even certain refractive procedures, can alter the corneal curvature and introduce or increase astigmatism. Similarly, an injury to the eye or eyelid that distorts the corneal surface may lead to new or worsening astigmatism that requires updated correction.

A chalazion (a firm bump on the eyelid), ptosis (a drooping upper lid), or other eyelid masses can press against the cornea and temporarily change its shape. In some cases, ongoing or recurrent eyelid pressure leads to measurable increases in astigmatism that resolve once the underlying lid condition is treated.

Pregnancy, uncontrolled diabetes, and certain hormonal changes can affect the shape and hydration of the cornea. These shifts are often temporary, but they may cause noticeable fluctuations in your astigmatism measurement. If your prescription seems to swing between exams, systemic health factors are worth discussing with your eye doctor.

Yes. Conditions such as early cataracts, dry eye disease, and corneal surface irregularities can all produce blurred vision, glare, and visual distortion that mimic increasing astigmatism. A thorough eye exam helps distinguish between a true change in astigmatism and other treatable causes of blurry vision. If you are noticing changes, an updated evaluation can clarify which factor is responsible.

While astigmatism usually changes gradually, sudden worsening can occur after eye trauma, during an acute episode of keratoconus progression, or if an eyelid mass begins pressing on the cornea. Sudden visual changes should always be evaluated quickly to rule out conditions that benefit from early treatment.

Keeping your glasses or contact lens prescription current is the single most effective step. Reducing prolonged screen time, using proper lighting while reading, and following the 20-20-20 rule (looking at something 20 feet away for 20 seconds every 20 minutes) can reduce the eye strain that often accompanies uncorrected astigmatism. Avoiding eye rubbing is also important, particularly if you are at risk for corneal thinning.

You should see an eye doctor if you notice increasing blur, new visual distortion, worsening night vision, or frequent headaches. Patients with a known history of astigmatism should have comprehensive exams at least once a year, or more frequently if their prescription has been changing. Young patients with progressive astigmatism may benefit from exams every six months to monitor for conditions like keratoconus.

Updated glasses and toric soft contact lenses correct mild to moderate astigmatism effectively. For irregular astigmatism or cases that do not respond well to standard lenses, rigid gas-permeable or scleral contact lenses can provide sharper vision. If keratoconus is the underlying cause, corneal collagen cross-linking can stabilize the cornea. Refractive surgery options such as LASIK or PRK may also be appropriate for stable astigmatism in eligible candidates. Our eye doctors will recommend the approach that best fits your diagnosis and visual goals.

You cannot prevent age-related changes in corneal and lens curvature, but you can reduce modifiable risk factors. Avoiding habitual eye rubbing, managing allergies that trigger the urge to rub, wearing protective eyewear during sports or work, and attending regular eye exams all help protect corneal health. For children and teens with progressing astigmatism, early monitoring allows timely intervention before significant visual impact occurs.