What is astigmatism? Causes, Symptoms, and Eyes Care Tips

What is astigmatism?

The refractive power of the eyeball on each meridian is uneven. After the parallel light enters the eyeball, it cannot focus on the retina. This is due to the eyeball's different refractive power on each meridian. It forms some scattered focal points instead.

What causes astigmatism?

Astigmatism is a refractive error. It happens when the cornea, the eye's clear outer layer, is irregularly shaped. This causes light to focus unevenly on the retina. Kids are more likely to have astigmatism if one or both parents have it. Poor eye habits, such as reading in poor lighting or squinting, can also cause astigmatism.

Through optometry, the visual effects of astigmatism in patients are identified. Astigmatism is an optical issue. It happens when the eye's cornea or lens is irregularly shaped. This prevents light from focusing properly on the retina. The irregular curvature causes light to scatter. This creates multiple focal points, leading to blurred or distorted vision. This condition can affect vision at all distances. It often occurs with other refractive errors, like myopia (nearsightedness) or hyperopia (farsightedness).

Astigmatism vs. normal vision

Astigmatism can't form a clear image. Adjusting focus or moving the target makes no difference. The lines look blurry. People with astigmatism may have poor vision compared to those with normal vision. This can be a problem, especially when driving at night.

What is a prescription for astigmatism?

An optometrist or ophthalmologist usually tests for astigmatism after a refraction test. An astigmatism prescription specifies the type and power of lenses to fix an irregularly curved cornea or lens. The key pieces of information are as follows:

Sphere (SPH): This indicates nearsightedness (myopia) or farsightedness (hyperopia) in diopters. Negative values ​​indicate nearsightedness and positive values ​​indicate farsightedness.

Cylinder (CYL): This measures the amount of astigmatism in diopters. It shows how much correction is needed to compensate for the irregular curvature of the cornea or lens.

Axis: This indicates the direction of the astigmatism in degrees, ranging from 0 to 180. It tells the direction to apply the cylinder correction to fix the astigmatism.

A complete vision prescription will also include other info, like OD, OS, and PD. Learning to read a vision prescription will help you understand your vision status.

Astigmatism Can Be Roughly Divided Into:

1. Regular astigmatism, irregular astigmatism;

2. Astigmatism along the rule, against the rule astigmatism, oblique axis astigmatism;

3. Simple myopia with astigmatism. Simple hyperopia with astigmatism. Compound myopia with astigmatism. Compound hyperopia with astigmatism. Mixed astigmatism.

4. Corneal astigmatism, crystal astigmatism, etc.

What are the hazards of astigmatism?

Astigmatism can cause headaches and blurred vision. Astigmatism prevents the eyeball from focusing parallel light rays on the retina. This can blur or double vision. People with astigmatic vision often squint to see clearly. This leads to fatigue and worsens their vision. Astigmatism makes your eyes work harder to focus. The eye muscles tense up, causing headaches over time.

What causes to astigmatism getting worse?

Astigmatism usually develops in childhood and stays stable for life. However, several factors may worsen it:

• Eye damage: Even minor eye damage can change the shape of the cornea, potentially increasing the severity of astigmatism.
• Keratoconus: This disease thins and bulges the cornea. It can cause severe astigmatism.
• Certain eye surgeries: LASIK and similar procedures usually fix astigmatism. But, they can sometimes change the cornea's shape and worsen it.
• Age: Although uncommon, some people may experience worsening astigmatism as they age due to changes in eye shape.
• Eye diseases: Some eye diseases, such as cataracts or dry eye, can cause astigmatism to worsen.
• Medications: Some, like antihistamines and decongestants, can cause dry eye syndrome. This can worsen astigmatism.
• Wearing Contact Lenses: Incorrectly fitted contact lenses can change the cornea's shape. This may worsen astigmatism.
• Excessive eye rubbing: Long-term eye rubbing can fatigue the cornea and lead to increased astigmatism.

Protect Your Eyes, Vooglam Recommends:

1. It is best to have regular eye examinations, 1 to 2 times a year. Develop good hygiene habits and do not touch your eyes with your hands or other objects to avoid spreading eye diseases.

2. The reading posture should be correct, keep a distance of 30cm~40cm, and the fonts should be clear and not too small when choosing reading materials.

3. Do not rub your eyes. Protect your eyes and avoid eye trauma. This is the way to prevent pathological astigmatism.

4. For patients with astigmatism, wearing prescription glasses promptly is important. The right prescription will reduce astigmatism symptoms. It will prevent eye fatigue when working and studying.