Astigmatism - Treatment of Astigmatism

Astigmatism is also commonly referred to as “astigmatism” or “spindle-shaped vision.” These terms are not entirely accurate, as astigmatism can also have other causes. Nevertheless, corneal astigmatism is the most common cause of spindle-shaped vision.

In astigmatism, the cornea of the eye is distorted. As a result, incoming light does not focus as a single point on the retina but is scattered across it. This leads to blurred vision. Astigmatism usually becomes noticeable only when it is more severe.

For example, through:

• Blurred vision at both near and far distances (unlike nearsightedness or farsightedness, where only one distance is affected)
• Headaches
• Eye pain
• Possible decline in visual acuity in children

Astigmatism is usually congenital. However, it can sometimes develop in adulthood. This can have various causes:

• Scars or ulcers on the cornea (for example, due to injuries or infections)
• Keratoconus: a change in the cornea that typically first appears during puberty or early adulthood.
• Eye surgery (for example, surgery for glaucoma)

There are various ways to treat astigmatism:

1. Vision aids: Such as glasses with a special cylindrical prescription, soft and toric contact lenses (which automatically align themselves on the curved cornea), and rigid gas-permeable contact lenses that restore the cornea’s proper curvature.
2. Surgery: Surgical options for astigmatism include laser surgery, artificial lens replacement, or corneal transplantation.

Discuss with your ophthalmologist which procedure is right for you.

It is now possible to have astigmatism corrected with laser surgery. To ensure the patient feels no pain during the procedure, the doctor numbs the patient’s eye with special eye drops. 

There are several methods that an ophthalmologist can now use:

• Photorefractive keratectomy (PRK)

In photorefractive keratectomy, the laser removes the inner layer of the corneal surface to smooth out irregularities and correct the refractive error.

• Laser Epithelial Keratomileusis (LASEK)

Laser epithelial keratomileusis is a further development of PRK. The doctor first wets the surface of the cornea with 20-percent alcohol and then pushes it aside as an intact layer of cells. After the laser treatment, the surface slides back into its original position.

• Laser in situ keratomileusis (LASIK)

In laser in situ keratomileusis, the doctor separates the upper layer of the cornea with a thin scalpel and folds it upward. The LASIK laser then reshapes the inner surface of the cornea to correct the refractive error. Finally, the doctors flip the corneal flap back into place.

After the surgery, vision will fluctuate for about four to six weeks. After that, it stabilizes. Immediately after the procedure, the eye will water more than usual. The surgery itself is painless.

Refractive lens exchange (RLE) is suitable for very severe vision defects that cannot be treated with LASIK. Several preliminary examinations are required for RLE to determine the appropriate lens.

The cornea itself remains unchanged during the procedure. An ultrasound device breaks up the natural lens and replaces it with an artificial one (intraocular lens). Finally, doctors suction out the natural lens.

The shape of the lens is selected to correct the astigmatism. RLE is a routine procedure and painless. Follow-up corrections can be easily performed. The hospital stay for RLE lasts a maximum of one week. Shortly after the procedure, you must refrain from sports and avoid wearing makeup.

Doctors perform a corneal transplant when corrective lenses or laser surgery have been unsuccessful. During a corneal transplant, the patient receives a cornea from a donor. Experts also refer to this procedure as keratoplasty.

In penetrating keratoplasty, doctors transplant the entire central portion of the cornea @ Nastya Trel /AdobeStock

Before the patient receives the donor cornea, doctors carefully screen it for communicable diseases.

Doctors then remove the old cornea with a cutting instrument and suture the new, custom-fitted donor cornea in place using threads as fine as a strand of hair. The sutures are removed after about a year. 

As long as the sutures remain in the eye, the patient cannot achieve their final visual acuity. The actual outcome of the surgery is therefore not apparent until about a year later. 

The following complications may occur during a corneal transplant:

• The body rejects the donor cornea. The cornea becomes cloudy. 
• The original condition spreads to the new cornea. 

However, in most cases, it is possible to perform a repeat corneal transplant. The surgery is performed under general or local anesthesia.