What irregular astigmatism is and how it is treated

02/12/2025

Astigmatism is a common visual problem that occurs when the cornea (the transparent layer that covers the eye) does not have a perfectly round shape. Instead of having a uniform curvature like a soccer ball, it has a shape more similar to a rugby ball, which, depending on its severity, causes blurry or distorted vision.

When this irregularity in the shape of the cornea is uniform and predictable, it is called regular astigmatism, and it is usually corrected easily with glasses or soft contact lenses. However, when the surface of the cornea presents deformities or scars that make the curvature vary unpredictably at different points, irregular astigmatism occurs. Its correction is much more complex because even with glasses it is not possible to achieve good vision, which can compromise quality of life.

The most common causes of irregular astigmatism include:

• Keratoconus: a progressive disease in which the cornea thins and deforms, taking on a cone shape.
• Corneal scars from infections, trauma, or previous surgeries.
• Corneal degenerations or complications after corneal laser refractive surgery, such as LASIK.

People with irregular astigmatism may notice these symptoms:

• Blurry or distorted vision, both at distance and near, that does not improve with glasses.
• Difficulty seeing at night.
• Light sensitivity.
• Headaches or visual fatigue.

The treatment will depend on the cause and severity. Some options include:

• Rigid or scleral contact lenses: they compensate for corneal irregularities and significantly improve vision.
• Intracorneal rings: implanted in the cornea to regularize its shape and improve vision with glasses.
• Corneal crosslinking: in cases of progressive irregular astigmatism, it allows the progression of corneal deformation to be stopped.
• Corneal transplant: in more advanced cases.

It is important to consult an ophthalmologist if you have poor vision that does not improve with glasses, or a progressive increase in astigmatism. Early diagnosis can make a difference in preserving vision and quality of life.

Dr. Paola Sauvageot, ophthalmologist at the Barraquer Ophthalmology Centre