How does vision appear with astigmatism, and how can it be corrected?

Astigmatism is a refractive error where the curvature of the cornea—the transparent dome forming the front part of the eye—is asymmetrical rather than naturally spherical.

In some cases, it may also result from abnormalities in the crystalline lens, the natural internal lens of the eye located just behind the iris.

"Astigmatism prevents light from focusing properly on the retina, leading to blurry or distorted vision at any distance," explains Dr. Belotti.

The human eye functions like a camera: the cornea and crystalline lens refract light to project a sharp image onto the retina, which then sends signals to the brain. In a normal eye, the cornea has a regular spherical shape, similar to a soccer ball. In astigmatism, however, the cornea is shaped more like a rugby ball. This irregular shape causes light rays to focus on multiple points on the retina instead of a single point, resulting in blurred vision.

In most cases, astigmatism is genetic, meaning a person is born with it. It is classified as a "refractive error," a non-pathological alteration of vision that causes unclear and undefined images of the surrounding world.

Astigmatism can also be caused by pathological conditions such as:

• Eye injuries
• Post-surgical effects
• Corneal diseases such as keratoconus

"Refractive errors, which are usually corrected with glasses or contact lenses, include myopia, hyperopia, astigmatism, and presbyopia," Dr. Belotti specifies.

Common symptoms of astigmatism include:

• Blurry vision and difficulty distinguishing details at any distance
• Eye strain and discomfort
• Headaches

Additional symptoms may include excessive sensitivity to light, eye redness, and burning sensations if the condition is not properly corrected. Other possible signs include:

• Frequent blinking
• Squinting
• Tilting the head to the side when looking at objects

"These symptoms are particularly noticeable during activities requiring intense visual concentration, such as reading, using a computer, or driving at night," warns Dr. Belotti.

Regular eye examinations, especially in children and adolescents, are crucial for identifying and correcting visual defects in their early stages.

"The first eye exam should be performed at birth, and a child with normal development should undergo a comprehensive eye examination at the age of three, even if they show no symptoms," advises Dr. Belotti.

"Astigmatism is diagnosed through a comprehensive eye exam, which includes tests such as:

• Refraction measurement
• Retinoscopy (which measures the eye's refractive error)
• Autorefractometry (objective assessment of refractive defects)
• Cycloplegic evaluation (using eye drops that temporarily relax the internal ocular muscles)
• Corneal topography (which analyzes the shape and curvature of the cornea)," Dr. Belotti explains.

Treatment for astigmatism varies based on the severity of the condition and the patient’s needs. Options include:

• Glasses
• Contact lenses
• Laser treatments, including PRK, femtoLASIK, and SMILE, which effectively correct astigmatism

Laser Techniques and Surgery for Permanent Correction

Laser procedures such as PRK, femtoLASIK, and SMILE reshape the cornea to improve its curvature and focusing ability. These treatments are suitable for individuals who wish to eliminate dependence on glasses or contact lenses.

"For cases of high astigmatism that cannot be treated with laser surgery, intraocular toric lens implantation is a definitive correction method," explains Dr. Belotti.

"This surgical technique, a point of pride for our ophthalmology department, can also correct associated refractive errors, such as severe myopia or hyperopia, which are not treatable with laser surgery, particularly when combined with cataracts (the clouding of the natural crystalline lens).

In these cases, a single procedure can resolve both the vision defect and the cataract," concludes Dr. Belotti.