Astigmatism Overview:

An inadequacy in the cornea’s curvature is called astigmatism. Normally, the cornea is smooth and curved equally along the dimensions. Even the lens has the same features. When any of these are not smoothly curved, the refraction of light rays does not happen properly. This can lead to refractive error. When the problem is with the irregular shape, then it is called corneal astigmatism, and it is called lenticular astigmatism when the problem is with the shape of the lens. When affected by astigmatism, the vision is not clear and objects look blurred. One can see the images as in a funhouse mirror. The images are thin and long, or thick and short. Astigmatism can also be present since birth, and it is seen that most of them have some sort of this condition by birth. Unfortunately, children are not aware of this condition, as in adults, who can identify that something is wrong with their vision.

There are 3 types into which the condition is categorized:

1.       Myopic astigmatism:

This is a condition where the meridians, maybe one of them or both the principal meridians, are nearsighted. When both the meridians are nearsighted, then they myopia is seen with different degrees.

2.       Hyperopic astigmatism:

In this condition, the principal meridians are farsighted. Again, this can be either one of them or both. If both are farsighted, then the degree of hyperopia differs.

3.       Mixed astigmatism:

Here, one of the principal meridians is farsighted and the other is nearsighted.

The condition of astigmatism is also classified into two, as regular and irregular astigmatism. This happens when the principal meridians are 90 degrees apart. In other words, they are perpendicular to each other. In the majority of people, it is regular and corneal astigmatism. This means the front eye surface gets an oval shape. When there is a scarring in the cornea, caused due to an eye injury, the condition is called irregular astigmatism.

Astigmatism Symptoms:

-  Blurred vision : this is the most common symptom of astigmatism. In case of a doubled or blurred vision, many people rule out the same claiming to be eye strain or overworking. In many people, a slight blurriness is not going to cause any damage or defect. So, they tend not to notice it. Only in advanced stages of the most significant astigmatism, the sufferer sees that the vision is really blurred. In fact, in kids, this is never realized by them. So, the best thing to do is to schedule eye tests for the kids from the early ages.

-  Blurring of small print : While many tend to overlook blurriness when they find it hard to read the small prints, and find difficulty in reading, understand that their ophthalmologist has to intervene.

-  Double vision : Unless one is too worn out, or hung over, double vision is not something common. Double vision indicates that astigmatism needs medical attention immediately.

-  Squinting : Though squinting can be seen as a common sign in many, the people suffering from astigmatism would not be able to see the things that are both close and far off, without squinting.

In children, there can be other symptoms as well.

- Difficulty in reading: Reading the prints can be a difficult task for kids. They would not be able to read the lines. This can have a negative impact on their studies.

- Eye strain: Due to overworking as they cannot read lines and sentences, eye strain is common in children suffering from astigmatism.

- Headaches: With eye strains, headaches cannot be ruled out.

- Astigmatism is a refractive error. When the cornea or lens are not matched in the shapes, this results in a blurry image. This condition is caused when the light rays cannot bend properly.

- When the cornea or lens is more steeply curved, in one direction compared with another direction.

- The blurred vision can be more in one direction, horizontally, diagonally or vertically.

- This condition can exist from birth to many. In a few, this can be because of an injury.

- At times, astigmatism can be caused after an eye surgery

- Keratoconus, a rare condition can also lead to astigmatism in many cases. The cornea becomes very thin or turns into the shape of a cone gradually. This leads to poor vision, and eyeglasses are not the solution here. Contact lenses only can be used, and the patients might need a corneal transplant.

Diagnosis of Astigmatism

A range of eye tests is conducted by the doctor to find out about the condition.

Vision test:

One has to read the letters on a chart that is 20 feet away, and if the vision is 20/20, it means as a normal person, one can read the letters from 20 feet. If the vision is 20/80, one has to be in the distance of 20 feet, while a normal person can read the letter from the distance of 80 feet.

Refraction:

A phoropter is swung in front of the affected individual’s eyes. The affected needs to help the doctor, to find which lens offers the best vision. A retinoscope can also be used at times. Based on the results, the doctor prescribes glasses.

Keratometry:

The bend in the centre of the cornea is measured using this device. The steepest and flattest curves are measured. The shape of the cornea and its focus are determined by the doctor, and this can help in determining the right contact lenses.

Corneal topography:

The shape of the cornea is accurately given by this advanced technology. A specific object has to be looked at by the patient. Colossal amounts of tiny measurements are collected during this. The data is transferred to a computer which comes up with a colour map of the cornea. Based on the results, the doctor can find which the best-suited treatment for the condition is. The keratoconus, a disease that causes astigmatism can be also diagnosed with this test.

Astigmatism Prevention:

Unfortunately, no prevention can work for astigmatism. But, it is always possible to keep the condition from worsening. Here are some ways by which you can do the same:

- Preventing ocular strain is the most important stuff. Using a computer and television for a long time can lead to this condition. Using them after periods of intervals will not cause much damage.

- Reading in poor lighting too can cause ocular strain.

- Occupational hazards like involving too much fine detailed works can lead to ocular strain and can worsen the condition.

- Lack of nutrition to support the eyes’ health is another reason for the strain in the eyes

- Follow the 10-10-10 rule. When working on a computer, every 10 minutes look at an object that is 10 feet away for 10 seconds. Gazing at trees can offer care and relaxation to the eyes

- Blinking frequently helps in preventing dry eyes, and takes off the stress from the eyes

- Use proper lighting in the working space. LED bulbs are good alternatives when natural light is not present.

- Stress and irritation to the eyes can be taken off when a humidifier is used at home

- Green vegetables, egg yolks, orange pepper, black currants, blueberries, and Alaskan salmon are good choices of foods that can keep eyes healthy.

- Frequent visit to the ophthalmologist can help in early detection of the condition and help in preventing it from worsening.

Astigmatism Treatment:

Eyeglass lenses:

These lenses are curved to respond the curved nature of the cornea. This can prevent the blurred vision.  The correction, however, is not going to help 100%. This is because wearing glasses can help only when looking straight.   The walls and floor can look tilted, if much correction is needed. But, getting used to them can help in keeping this off after a few weeks. In case of severe astigmatism, it takes a couple of weeks. When the sight is not getting any better, consulting the doctor again is significant.

Contact lenses:

Like glasses, these can help a lot too. But there are soft lenses called toric lenses. Only these can be used for astigmatism. When contact lenses are used, they keep rotating when blinked. These special lenses are designed to get back to the same spot after rotating.

Lasik:

This laser eye surgery helps in reforming the cornea’s shape. This helps in the better focus of the light rays. A sterile mechanical device is used after the eyes are numbed. A thin flap of the camera is created on the cornea. The central layers are exposed when the thin flap is pulled out. Then the laser is used to sculpt the cornea. The flap again gets back to the original position. Then the doctor gives anti-inflammatory eye drops and covers the eyes with transparent sheets. This is an expensive procedure, and not all insurance companies cover this. While it works for the majority of the people, there are a few pitfalls too. A follow-up surgery is required, as the procedure can over-correct or under correct the vision. The glaze can be present, which means seeing lights at night is not comfortable. The dryness in the eyes tends to increase after the Lasik surgery. Reading glasses are required for people who are over 40. But, when the monovision technique is used, glasses can be seldom required. This means, one eye is used for nearby objects and the other for far-off objects.

Laser-assisted subepithelial keratectomy (LASEK):

This is the same laser technology with some modification. Here, no tiny flap is created. The cornea has a thin protective cover called epithelium, and it is done with a special alcohol. This is loosened by the surgeon during this surgery. The cornea’s curvature is changed using the excimer laser, and then the protective layer which is loosened is repositioned.

Photorefractive keratectomy (PRK):

This is similar to the previous procedure LASEK. The only change is that the surgeon removes the epithelium in this procedure. The epithelium can always grow back, and the good news is that it confirms the new shape of the cornea. However, wearing a bandage and contact lens after the surgery is mandatory for a few days.

Epi-LASEK:

This is another version of LASEK too. Instead of special alcohol, a blunt blade is used by the surgeon. The thin sheet of epithelium is separated by this blunt blade. The excimer laser is used to reshape the cornea. Again, the epithelium is repositioned after this procedure.

Many other refractive surgeries are also coming in these days. This includes the use of extractable and implantable contact lenses. The surgeon is the best person to decide what best fits the patient.

Astigmatic keratotomy:

This is called a limbal relaxing incision. The steepest curves of the cornea get tiny cuts. This means that the light is getting focused on the retina more precisely. But this is not going to work for the severe cases. A laser surgery is often required.

Astigmatism Complications :

When left untreated, this can lead to severe vision problems. It can also lead to the condition called amblyopia, also known as the lazy eye. The brain tends to go in favour of the healthy eye if the blurry vision occurs only in one eye. The vision of the affected eye can go underdeveloped, as it never gets proper attention from the brain. This again leads to permanent vision issues, and poor depth perception is also on the cards. Getting to know the risk factors for this condition can help stay in the best place.

- When there is a family history of astigmatism, one can find the risk factor high

- Thinning or scarring of the cornea

- The blurry vision of objects at a distance or too much of nearsightedness can also end up in astigmatism. The same is the case with the excessive farsightedness.

- Surgical removal of the clouded lens and cataract surgery can result in astigmatism.

As aforementioned, astigmatism can never be prevented, and it can be existing from birth. Children, unfortunately, cannot detect the same, and end up with serious vision complications. The only way out is to consult an ophthalmologist when the symptoms are seen. Also, it is important to schedule a visit to the eye doctor at least once a year.

Last updated on : 21-09-2018

Disclaimer : Docprime doesn’t endorse or take any guarantee of the accuracy or completeness of information provided under this article and these are the views strictly of the writer. Docprime shall not be held responsible for any aspect of healthcare services administered with the information provided on this article.

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