Irregular astigmatism Astigmatism is one of the most common refractive errors that causes blurred vision and may affect people of any age. This disease occurs when the front surface of the eye (cornea) has an inappropriate curvature. Astigmatism is not only limited to the cornea and can also be due to improper curvature of the intraocular lens. To better understand this problem, you can imagine the surface of the natural cornea as a round ball. An eye with regular astigmatism is oval in shape and its curvature is not the same in all directions. In irregular astigmatism, the cornea is like a squashed ball whose surface is uneven and asymmetrical, and its curvature is not the same in all directions and does not change regularly. In a healthy eye, the light rays after hitting the cornea and lens are properly focused on the retina and a clear image is created. But in irregular astigmatism, due to the asymmetric curvature, the light rays are irregularly focused on the retina and finally a clear image is not created. Irregular astigmatism is less common than regular astigmatism. You can find out the type of astigmatism of your eyes by visiting an eye doctor and performing detailed examinations. In this article, we are going to provide more information about irregular astigmatism. **Read more: Astigmatism eye LASIK operation** Symptoms of irregular astigmatism The symptoms of this disease may vary from person to person. By knowing the symptoms of irregular astigmatism, it can be diagnosed faster so that appropriate treatment measures can be taken. Its important and main symptoms are: - ### blurred vision: Blurred vision is one of the important and main symptoms of astigmatism, and the images are of lower quality and are seen without details. - ### double vision: Due to the irregular curvature of the cornea or lens, light rays are concentrated in several points of the retina and cause double vision. - ### Headache and dizziness: Prolonged focus on objects or visual activities causes extra strain on the eyes and causes frequent headaches. - ### Fatigue and eye pain: Tiredness, pressure and pain in the eyes are among the symptoms of irregular astigmatism that occur after long visual activities such as reading, working with a computer or mobile phone. - ### Vision problem at night: At night and in very low light, due to the expansion of the pupil, more light enters the eye and as a result, halos and dazzling lights are seen. Causes of irregular astigmatism In general, people suffer from genetic or acquired irregular astigmatism. Any factor that causes disorder in the cornea and irregular changes and finally changes the shape and deviation of the cornea is considered to be one of the causes of irregular astigmatism. The most common cause of irregular astigmatism is keratoconus, which causes thinning and deformation of the cornea. Corneal infections or inflammations cause this type of astigmatism by causing wounds and scars on the cornea. Also, damage or physical trauma to the eye, such as hitting the cornea and cutting it, can cause irregular shape changes and corneal deviation. In addition to the mentioned cases, in some eye surgeries such as corneal transplant, the curvature of the cornea may not completely return to its original state, thus causing irregular astigmatism. Diagnosis of irregular astigmatism It is very important to have regular eye examinations by an ophthalmologist. If you see any of the symptoms, be sure to see an eye doctor to determine the cause. Irregular astigmatism can be diagnosed by performing detailed and complete eye examinations. These examinations include vision test, measurement of refractive error, keratometry and examination of corneal convexity with corneal topography. The vision test is one of the primary tests that determine the clarity of a person's vision at different distances. Refraction measurement is done using a tool called retinoscope, which determines the type and amount of refractive errors by shining light into the eye and checking its reflection from the retina. Keratometry, by measuring the curvature of the cornea, plays an important role in diagnosing and evaluating astigmatism. A more accurate diagnosis of this disease requires more specialized methods such as corneal topography. Corneal topography provides a more accurate picture of the surface of the cornea and its irregularities and helps the ophthalmologist to diagnose irregular astigmatism and diseases such as keratoconus. **Read more:** **Astigmatism eye laser procedure** Prevention and treatment of irregular astigmatism In general, there is no definitive prevention for this disease, but regular and accurate eye examinations and early diagnosis play an important role in preventing the development of this disease. A patient with astigmatism must be examined by an ophthalmologist and according to the specific conditions of each person's eyes and the severity of astigmatism, the appropriate treatment option should be chosen for that person. In general and in summary, the ways to treat this disease are: - ### Glasses: Prescribing corrective glasses is one of the ways of treatment in mild cases. - ### contact lenses: Using contact lenses is one of the most common ways of treatment. Rigid contact lenses (RGP) and scleral lenses compensate for the irregular curvature of the cornea and create a smooth and uniform surface on the cornea; As a result, they provide a clearer view. - ### Surgery: In mild cases, laser surgeries such as PTK or PRK can be used to even out the irregular curvature of the cornea. But in very severe cases of irregular astigmatism, especially if it is caused by keratoconus, it may be necessary to perform a cornea transplant. **Conclusion** Irregular astigmatism is one of the common vision disorders caused by the irregular curvature of the cornea and lens, which can be well controlled if diagnosed and treated in time. If you see symptoms such as blurred vision, frequent headaches, or eye fatigue, be sure to see an eye doctor for timely diagnosis and correct treatment, according to the condition of the eyes and the severity of irregular astigmatism.