What is Astigmatism? Treatment and Symptoms

What is Astigmatism? Treatment and Symptoms

Astigmatism is a refractive error that occurs because the cornea or lens of the eye is not curved properly. This prevents light from focusing on the retina at a single point, causing the image to appear blurry, distorted or shadowy. It is usually congenital, but it can also develop as a result of eye trauma, surgery or corneal diseases. Astigmatism is often accompanied by myopia or hyperopia and can affect both near and distance vision. It can be easily diagnosed with regular eye examinations; It can be treated with glasses, toric contact lenses or laser eye surgery.

What is Astigmatism?

Astigmatism, in medical literature, is a refractive error that occurs due to the cornea or lens of the eye not being curved properly. Normally, the cornea and lens refract light equally as it enters the eye and direct it to a single focal point. However, in the case of astigmatism, these surfaces are irregular; Light is not concentrated at a single point on the retina, but is instead focused on multiple points. This causes the image to be perceived as blurry, distorted or shadowy. Astigmatism can often be seen together with myopia (farsightedness) or hyperopia (nearsightedness). This eye deformity is usually congenital; However, it may progress with age and may also occur after eye trauma.

What Causes Astigmatism?

The answer to the question of what causes astigmatism is mostly based on structural defects of the cornea located in the front of the eye or the lens inside the eye. The eye must refract incoming light properly and focus it exactly on the retina. However, in astigmatism, this refraction process is not smooth; The cornea or lens has an oval shape, causing light to fall on more than one point.

• Eyelid Printing — Long-term and continuous eye rubbing can cause the cornea to become deformed over time.
• After Eye Surgery — Irregular healing, especially after stitched cataract surgeries or corneal surgeries, may lead to the development of astigmatism.
• keratoconus — This progressive disease, in which the cornea thins and takes the shape of a cone, constitutes a severe form of astigmatism.
• Corneal Traumas — Cutting or penetrating injuries to the eye can damage the corneal structure and cause astigmatism.
• Genetic Predisposition — Astigmatism is mostly congenital. Having this eye defect in the family increases the risk.

What are the types of astigmatism?

• Myopic Astigmatism — Along with astigmatism, there is also myopia (inability to see clearly in the distance). The patient sees blurred objects, especially distant objects.
• Hyperopia Astigmatism — Astigmatism is accompanied by hyperopia (inability to see near clearly). The person has difficulty seeing at close distance and eye fatigue is common.
• Mixed Astigmatism — One axis of the eye is myopic and the other axis is hyperopic. There is blurriness in both near and far vision; It is the type with the lowest visual quality.
• Regular Astigmatism — Corneal curvature is symmetrical but elliptical rather than round. It is usually congenital and is easily corrected with glasses or contact lenses.
• Irregular Astigmatism — The corneal curvature is not only symmetrical but also distorted in different directions. It usually occurs after corneal trauma, keratoconus or previous eye surgeries; Special hard contact lenses or laser treatment may be required.

How Does Astigmatism See?

Astigmatism patients may see objects distorted, double or blurred. When glasses or contact lenses are not used, the image becomes distorted and clarity is lost. Difficulty in focusing, difficulty in dim light, burning and redness in the eyes, headache and eye fatigue are common complaints. These impairments in visual perception can cause a decrease in performance in people's social and professional lives.

Astigmatism Symptoms

• Blurred or Distorted Vision — There is a loss of clarity at both near and far distances. Letters and shapes may appear wavy or shadowy.
• Headache and Eyestrain — Reading a book for a long time, looking at a computer screen, or doing tasks that require attention triggers this condition.
• Night Vision Challenge — Visual quality decreases due to light scattering and reflections, especially while driving.
• Double Vision — It is possible to perceive the same object as more than one reflection, especially with one eye.
• Frequent Blinking and Rubbing — Eye reflexes may increase due to visual effort; Overuse of eye muscles causes redness and stinging sensation.
• Difficulty Focusing — The eyes make more effort to clarify the image; There is a need to constantly squint the eyes to see clearly.

How to Prevent Astigmatism?

• Eye Hygiene — Failure to comply with hygiene rules, especially in contact lens users, can lead to infection and deformity of the cornea.
• Regular Eye Examination — Visiting an ophthalmologist regularly from an early age is important in terms of monitoring the progression of astigmatism and timely intervention.
• Working in Suitable Light — Reading and writing in dark or dimly lit environments can strain the eyes, leading to headaches and eyestrain.
• Screen Distance — It is recommended to rest your eyes at regular intervals during long-term computer or phone use.
• Avoid Rubbing Your Eyes — Continuous and vigorous rubbing of the eyes can negatively affect the corneal structure; It should be monitored carefully, especially in children.
• Protection from Eye Traumas — Impacts and accidents that may damage the corneal structure should be avoided; Protective glasses should be used while doing sports.

Astigmatism Diagnosis

• Visual Acuity Test — Blurry or distorted appearance of letters on the Snellen chart may raise suspicion of astigmatism.
• Otorefraktometre — Automatically measures the focusing ability of the cornea and eye lens; It provides initial data about the presence and degree of astigmatism.
• Subjective Refraction — “Is it clearer or blurrier?” By asking different prescription lenses, the diopter that provides the best vision is determined.
• Keratometry — It measures the curvature of the cornea in horizontal and vertical planes; If the curvatures are not equal, it indicates astigmatism.
• Corneal Topography — It is an advanced imaging method that maps the corneal surface; It is especially critical before laser surgery.

Astigmatism Test

Astigmatism testing is a routine practice often performed when preparing eyeglass prescriptions. However, test cards consisting of special drawings can also be used for astigmatism testing. In these tests, the person is shown various lines and geometric shapes; If the lines are not seen with equal clarity, astigmatism is suspected. Tests performed at an early age, especially in children, are very important in preventing eye problems that may occur in the future.

Astigmatism Treatment

Astigmatism treatment is planned individually. One of the most commonly used methods is glasses with cylindrical lenses that compensate for the difference in curvature of the cornea. For those who prefer contact lenses, specially structured lenses called toric lenses are used; These lenses provide clear vision by directly correcting the irregularity in the cornea. For those looking for a permanent solution, astigmatism is corrected by reshaping the corneal surface with laser methods such as LASIK, PRK and SMILE. These surgeries are generally performed on people over the age of 18, whose eye number has not changed in the last year and whose corneal thickness is appropriate.

Eye Laser Surgery for Astigmatism Treatment

• LASIK — It is based on the principle of lifting a thin valve to the upper layer of the cornea and shaping the lower layer with a laser. It provides quick recovery and is painless.
• PRK — It involves completely peeling off the surface layer of the cornea and reshaping the underlying tissue with a laser. It is preferred in people with thin corneas; The healing process is a little longer.
• SMILE — The refractive error is corrected by removing tissue from the inside of the cornea in a minimally invasive manner. The risk of dry eyes is lower and the healing process is faster.

Frequently Asked Questions