Causes, Types, Symptoms & Treatment

Astigmatism is a typical imaginative and prescient drawback brought on by an error within the form of the cornea. With astigmatism, the lens of the attention or the cornea, which is the entrance floor of the attention, has an irregular curve. This will change the way in which gentle passes, or refracts, to your retina, inflicting blurry, fuzzy, or distorted imaginative and prescient.

Farsightedness and nearsightedness are two different varieties of issues with the way in which gentle passes to your retina. Farsightedness is known as hyperopia. Nearsightedness is known as myopia.

On this article, we delve deeper into astigmatism, together with varieties, who’s in danger for it, and the way it’s identified and handled.

The 2 essential varieties of astigmatism are corneal and lenticular. A corneal astigmatism occurs when there’s a defect or distortion within the cornea. A lenticular astigmatism occurs when there’s a distortion within the lens.

Astigmatisms are typically additionally described as common or irregular. A daily astigmatism happens when the attention isn’t fully curved. So as a substitute of being spherical like a basketball, it’d take the form of a soccer. This usually results in blurry, distorted imaginative and prescient.

An irregular astigmatism, which is much less widespread, additionally happens when the attention isn’t fully spherical. However not like an everyday astigmatism, the place the attention is evenly misshaped, an irregular astigmatism has an uneven curvature. This defect additionally causes distorted imaginative and prescient and blurriness.

Illustration showing normal eye vs. astigmatismShare on Pinterest
Astigmatism is brought on by uncommon curvature within the eye’s lens or cornea that stops gentle from being centered into the point of interest of the retina. This leads to decreased imaginative and prescient or blurry imaginative and prescient. Illustration by Alyssa Kiefer

It’s not identified what causes astigmatism, however genetics is an enormous issue. It’s usually current at delivery, however it could develop later in life. It might additionally happen because of an damage to the attention or after eye surgical procedure. Astigmatism usually happens with nearsightedness or farsightedness.

Typically, although, a uncommon situation referred to as keratoconus causes astigmatism. This eye illness impacts the cornea, inflicting the clear tissue on the cornea to skinny and bulge out. This results in cloudy or blurry imaginative and prescient, and sensitivity to vibrant lights. The reason for keratoconus can also be unknown, nevertheless it’s believed to be hereditary, too.

Needless to say whereas studying with low or dim lights could make it more durable for eyes to focus, it doesn’t hurt imaginative and prescient or trigger astigmatism. Nonetheless, if you have already got a watch with astigmatism, and also you learn in low gentle, you would possibly discover elevated blurriness.

Astigmatism is a kind of refractive error. These are widespread eye issues that make it tough to see clearly. The form of the attention is unable to bend gentle accurately, and in consequence, imaginative and prescient can turn out to be hazy, blurry, or doubled.


Nearsightedness (myopia) is a kind of refractive error that makes distant objects seem blurry or distorted. Different signs can embody complications, eye pressure, and squinting. Nearsightedness occurs when the eyeball is just too lengthy, or when the cornea curves an excessive amount of.


However, farsightedness (hyperopia) is an incapability to deal with objects up shut — however you’re in a position to see distant objects clearly. This imaginative and prescient drawback occurs when your eyeball is just too quick, or when the cornea doesn’t curve sufficient.

Astigmatism can happen in youngsters and adults. Your danger of growing astigmatism could also be greater when you’ve got any of the next:

  • a household historical past of astigmatism or different eye issues, similar to keratoconus (degeneration of the cornea)
  • scarring or thinning of your cornea
  • extreme nearsightedness, which creates blurry imaginative and prescient at a distance
  • extreme farsightedness, which creates blurry close-up imaginative and prescient
  • a historical past of sure varieties of eye surgical procedure, similar to cataract surgical procedure (surgical elimination of a clouded lens)

The signs of astigmatism might differ in every particular person. Some individuals don’t have any signs in any respect. The first signs of astigmatism embody:

  • blurry, distorted, or fuzzy imaginative and prescient in any respect distances (up shut and much away)
  • problem seeing at night time
  • eyestrain
  • squinting
  • eye irritation
  • complications

See a physician when you’ve got signs of astigmatism. Some signs can also be attributable to different well being or imaginative and prescient issues.

An optometrist or ophthalmologist diagnoses astigmatism by a complete eye examination.

  • An optometrist is a physician who diagnoses imaginative and prescient issues and eye ailments.
  • An ophthalmologist is a physician who gives medical and surgical therapy of imaginative and prescient issues and eye ailments.

There are a number of exams optometrists and ophthalmologists might use throughout your eye examination to diagnose astigmatism.

Visible acuity evaluation check

Throughout a visible acuity evaluation check, your physician will ask you to learn letters from a chart at a selected distance to find out how properly you’ll be able to see the letters.

Refraction check

A refraction check makes use of a machine referred to as an optical refractor. The machine has a number of corrective glass lenses of various strengths. Your physician will ask you to learn a chart whereas trying by lenses which might be completely different strengths on the optical refractor. They’ll finally discover a lens that appropriately corrects your imaginative and prescient.


Keratometry is a approach in your physician to measure the curvature of your cornea. They’ll do that by taking a look at your eye by a keratometer.

Astigmatism is measured in diopters, which is the optical energy of a lens. In case your eye doesn’t have astigmatism, you’ve got a diopter of 0. When you have one, although, you’ll possible have a diopter higher than 0.5. Remedy isn’t often obligatory for a slight astigmatism, however you would possibly want contacts or glasses for a diopter measurement of 1.5 or greater.

The one a part of an optical prescription related to astigmatism are the cylinder and axis. The cylinder a part of the prescription measures the diploma or extent of the irregularity. Docs use the axis measurements to find out the placement of a watch astigmatism on the cornea.

Gentle instances of astigmatism might not require therapy. Your physician might deal with astigmatism that causes imaginative and prescient issues through the use of one of many following strategies.

Corrective lenses

Corrective eyeglasses and get in touch with lenses prescribed by a physician are the commonest and least invasive remedies for astigmatism.

Orthokeratology (Ortho-Ok)

Orthokeratology (Ortho-Ok) is a therapy that makes use of inflexible contact lenses to briefly appropriate the irregular curvature of your cornea. You’ll put on inflexible contact lenses for restricted durations of time. Chances are you’ll put on them throughout sleep after which take away them in the course of the day.

Some individuals have clear imaginative and prescient in the course of the day with out corrective lenses when present process Ortho-Ok. The advantages of Ortho-Ok are solely current when utilizing it. Your imaginative and prescient will return to its earlier state after stopping Ortho-Ok.

Refractive surgical procedure

Your physician might advocate refractive surgical procedure when you’ve got a extreme case. Any such surgical procedure entails utilizing lasers or small knives to reshape your cornea. This may completely appropriate your astigmatism.

Widespread surgical procedures for astigmatism are:

All surgical procedures carry some dangers. Discuss to your physician in regards to the dangers and advantages earlier than getting surgical procedure for astigmatism.

If left untreated, astigmatism may cause issues. For instance, a lazy eye (amblyopia) can happen when an individual has astigmatism in just one eye, or the astigmatism in a single eye is worse than the opposite, and the situation isn’t corrected. Moreover, astigmatism can typically trigger eye pressure and complications.

Surgical procedure to deal with astigmatism additionally has dangers. Unwanted side effects of surgical procedure are sometimes short-term and enhance inside just a few weeks. These embody dry eyes, sensitivity to gentle, and night time imaginative and prescient issues.

However different (and extra everlasting) issues can happen, too, similar to imaginative and prescient loss or imaginative and prescient reverting to pre-surgery state.

The precise reason behind astigmatism isn’t identified, and therapy could be obligatory relying on the extent of this eye situation.

Carrying contact lenses or glasses can enhance imaginative and prescient, or your eye physician would possibly recommend surgical procedure. Remedy not solely helps imaginative and prescient, it could actually cut back the chance of issues like a lazy eye, eye pressure, and complications.

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