Astigmatism

Medical content revised by - Last revision 25/10/2017
Astigmatism

What is astigmatism?

Astigmatism is a defect in the curvature of the cornea (the dome-like transparent structure which covers the iris and the pupil) or in the shape of the eye lens.

Normally, the cornea and the lens are regular and are curved in the same shape throughout. This helps to focus light clearly onto the retina at the back of the eye. Nevertheless, if the cornea or the lens are not smooth or do not have a regular curve, the rays of light do not refract correctly, which causes a refraction problem.

 

astigmatismo

In a normal eye, the cornea and the lens focus the light onto the retina.

astigmatismo

In an astigmatic eye, the images get focused either in front of or behind the retina, which means that the images appear blurred.


Astigmatism of the cornea and the lens

Corneal astigmatism is when the cornea has an irregular shape. This is the more frequent type.

Nevertheless, there is also astigmatism of the lens in which case it is the lens that is deformed. Both cause near and far objects to appear blurred and distorted.


Regular and irregular astigmatism

  • Regular astigmatism. The principal meridians are perpendicular to each other and form a 90º angle. Most astigmatisms are regular and are of the cornea.
  • Irregular astigmatism. The principal meridians are not perpendicular. It may be the consequence of an injury or surgery that has caused the scarring of the cornea. In addition, it may be caused by a keratoconus, an eye problem which causes the thinning and deformity of the cornea.

Simple and compound astigmatisms

Simple astigmatism

  • Simple myopic astigmatism. One of the two principal meridians of the eye focuses light rays in front of the retina. The other focuses correctly onto the retina.
  • Simple hypermetropic astigmatism. One of the two principal meridians focuses rays of light behind the retina. The other focuses correctly onto the retina.

Compound astigmatism

  • Compound myopic astigmatism. The two main meridians of the eye focus light rays in front of the retina.
  • Compound hypermetropic astigmatism. The two principle meridians focus light rays behind the retina.
  • Mixed astigmatism. One principle meridian focuses the light in front of the retina and the other behind.

 

 


Symptoms

Some people are born with this defect. In fact, the majority have a certain degree of astigmatism that may be combined with other refraction defects, such as myopia or hypermetropia.

Adults with a high degree of astigmatism may realize that something is wrong with their vision due to blurred or distorted vision, visual fatigue, headaches, the need to squint to focus better or other visual problems which, although not necessarily indicating the presence of this refraction defect, do indicate the need to visit the ophthalmologist for a check-up.

In the case of children, they may not realize that they are suffering from this refractive defect, and may not complain of blurred or distorted vision. Nevertheless, if it goes uncorrected, it may affect the child’s performance at school. This is why it is essential that they see the ophthalmologist.


Correction of astigmatism

Normally, low to medium prescriptions can be corrected with glasses or contact lenses (soft or hard). In cases of higher prescriptions, glasses or hard contact lenses are normally more suitable, but this will depend on each specific case.

On the other hand, for some with this refractive defect, various surgical techniques may be an option for correcting their vision.

 

 

Related articles

Vision correction surgery

What is vision correction surgery? Vision correction surgery, or refractive surgery, is a type of ophthalmology dedicated to the study and treatment of myopia, hyperopia, astigmatism and presbyopia. The main objective is to improve your eyesight in order to avoid being dependent spectacles or contact lenses. Different surgical techniques have evolved to correct ocular refraction […]

Phakic intraocular lenses (PIOL)

Intraocular lenses are implanted in the eye to correct, generally, high myopia and hyperopia. They provide an excellent quality of vision and are especially indicated in cases of amblyopia or “lazy eye”. Recently, we have started to use state-of-the-art lenses that can also correct astigmatism efficiently. These lenses respect the ocular anatomy of the eye […]

Do you have any questions?

Contact us or request an appointment with one of our specialists.

Visit us at:

ICR Ganduxer Headquarters

c/Ganduxer,117
08022 Barcelona See map

ICR Pau Alcover

C. Pau Alcover 67
08017 Barcelona See map

ICR Terrassa

77, Del Nord St.
08221 Terrassa See map

Clínica Bonanova Surgical Center

Passeig Bonanova, 22
08022 Barcelona See map

Clinica Bonanova Tests and Treatments

c/ Mandri, 63
08022 Barcelona See map

ICR Service at Clínica Ntra. Sra. del Remei

c/ de l'Escorial,148
08024 Barcelona See map

ICR Ganduxer Headquarters

Telephone number 93 254 79 20
Emergencies phone number: 93 418 72 27

Opening hours:
Monday to Friday 8 a.m. to 8 p.m.
Saturdays 9 a.m. to 2 p.m.

How to get there More information

ICR Pau Alcover

Telephone number (+34) 93 378 23 19

Opening hours:
Monday to Friday from 8 am to 8 pm. Saturday from 8 am to 2 pm.

How to get there More information

ICR Terrassa

Telephone number +34 93 736 34 40

Opening hours:
Monday to Friday from 8:30 a.m. to 2 p.m. and 3 p.m. to 8 p.m.

How to get there More information

Clínica Bonanova Surgical Center

Telephone number 934 34 09 25

Opening hours:
Monday to Friday from 7:30 a.m. to 8:30 p.m.

How to get there More information

Clinica Bonanova Tests and Treatments

How to get there More information

ICR Service at Clínica Ntra. Sra. del Remei

Telephone number 902 10 10 50

Opening hours:
Every day from 3 p.m. to 8 p.m. and Friday mornings from 10 a.m. to 2 p.m.

How to get there More information

This website uses cookies in order to collect statistical information regarding navigation. If you keep on surfing this website, it shall be deemed to have acknowledged its use. More information.