Astigmatism
The cornea is a bulging disk-shaped membrane that allows light from outside to penetrate the eye structure to be projected onto the retina. For the cornea to function properly, it must be completely transparent and have the correct curvature.
El astigmatism occurs when the curvature of the cornea is not uniform, projecting the light that enters the eye at different points and providing blurred vision at all distances.
There are three types of astigmatisms and all can be corrected through a refractive surgery.
Astigmatism
The cornea is a bulging disk-shaped membrane that allows light from outside to penetrate the eye structure to be projected onto the retina. For the cornea to function properly, it must be completely transparent and have the correct curvature.
El astigmatism occurs when the curvature of the cornea is not uniform, projecting the light that enters the eye at different points and providing blurred vision at all distances.
There are three types of astigmatisms and all can be corrected through a refractive surgery.
What is astigmatism?
El astigmatism is a refractive error It causes blurred vision and distortion of images at short and long distance. Astigmatism originates when the cornea does not have the same curvature in all its parts and therefore adopts a elliptical or oval shape. The irregular curvature of the cornea causes the light entering from outside projects to different points on the retina, causing blurred vision or distorted
In most cases, astigmatism is an abnormality hereditary, that is, people are born with the defect and, as the years go by, the symptoms appear. astigmatism is usually accompanied by other refractive problems such as myopia and farsightedness.
Types of astigmatism
Astigmatism is classified according to the angle of their axes and according to the focal lines. In this way we have the following types of astigmatism:
Regular and irregular astigmatism
- At regular astigmatism, the two axes are located at right angles. This type of astigmatism is the most common and can be corrected using contact lenses or surgery.
- At irregular astigmatism, the two axes are not at right angles to each other. This type of astigmatism is usually caused by keratoconus.
Simple and compound astigmatism
El simple astigmatism it is one in which one of the focal lines is located on the retina and the other behind or in front of it. This type of astigmatism can be:
- Simple myopic: one of the two axes is myopic, that is, focuses in front of the retina and the other focuses on the retina.
- Simple hypermetropic: one of the two axes is hyperopic, that is, focuses behind the retina and the other focuses on the retina.
Simple myopic astigmatism
simple hyperopic astigmatism
El compound astigmatism it occurs when none of the focal lines rests on the retina and no axis is emmetropic, that is, without graduation. This astigmatism can be:
- Myopic compound: when the two axes are myopic, that is, they focus in front of the retina.
- Hypermetropic compound: when both eyes are hyperopic, that is, they focus behind the retina.
- Mixed: when one axis is myopic and the other hyperopic, that is, one axis focuses in front of the retina and the other behind.
Compound myopic astigmatism
compound hyperopic astigmatism
Mixed astigmatism
Causes of astigmatism
The irregular curvature of the cornea may be determined by the genetics of the person or hereditary factor, which considerably increases the probability of suffering from astigmatism, for corneal injuries, traumatisms in the eye or as a consequence of eye surgeriesand cornea transplant or a operation Cataracts.
What are the symptoms?
The astigmatism symptoms may vary according to type of astigmatism, the patient's age and graduation.
El main symptom of this refractive error is the distorted view of images at all distances, and the higher the graduation, the more severe the distortion. Apart from blurred vision, patients with astigmatism usually do not have any other symptoms. People with a high graduation of this refractive error usually perceive only small details at all distances, due to the effort that the eye makes to focus.
If astigmatism is accompanied by farsightedness, the patient can experience headache, visual fatigue, difficulty changing distance to near vision, itching y redness of the eye. Why does astigmatism have no symptoms? This is due to the accommodating power of the lens of the eye that tries to attenuate the defect in vision making changes and movements that allow you to better focus the images.
Astigmatism treatment
Astigmatism is a defect that can be temporarily corrected by wearing glasses or contact lenses, especially indicated in those with very high rankings o aversion to the operating room.
If we want definitively eliminate the use of glasses or contact lenses we make a astigmatism operation through refractive surgery.
Patients with keratoconus may consider the option of undergoing a symmetric mini radial keratotomyfor that avoid the cornea transplant and try both keratoconus and astigmatism that produces.
Astigmatism operation
There are various surgical options that allow us to eliminate astigmatism permanently. Among the techniques to correct astigmatism we have the laser techniques (FemtoLasik, LASIK y PRK) or the toric intraocular lens implant.
Additionally, eye surgery to eliminate astigmatism allows us to simultaneously correct myopia, hyperopia and presbyopia in the same intervention.
FemtoLasik
laser eye surgery FemtoLasikis the surgical technique for correct astigmatism most modern that exists today.
This technique is characterized by being a all-laser eye intervention to correct the astigmatimo. The main difference with Lasik is that the cut in the cornea (flap) has evolved and instead of being done by means of a blade (microkeratome) performed with a femtosecond laser.
This advance in combining the two lasers makes astigmatism intervention Safer y more predictable and we have greater control.
LASIK
La lasik surgery is technique most used today to operate with laser refractive defects such as myopia, hyperopia and astigmatism. The operation consists in making a very small incision in the superficial tissue of the cornea, to then apply the excimer laser scheduled by the specialist doctor.
The excimer laser helps mold imperfections of the curvature of the cornea to correct astigmatism and any other defect. The hard procedure 10 minutesit's ambulatory and is done under the influence of anesthetic eye drops.
PRK
La PRK surgery is carried out separating the corneal epithelium with a special alcoholic substance. Once the epithelium has been separated, the doctor will apply the excimer laser, previously programmed, to correct the defects that cause graduation. When it finishes correct astigmatism, the surgeon puts the epithelium back in its place and put some contact lenses that the patient must bring to protect the operated eye.
Like Lasik surgery, the PRK operation for astigmatism is ambulatory, hard 15 minutes and is done under the influence of anesthesia applied in drops.
Toric intraocular lens
Another alternative to correct astigmatism is the implantation of an intraocular lens, a highly recommended option for patients who are not candidates for laser surgeries such as FemtoLASIK, Lasik, or PRK.
All the toric intraocular lenses are designed for treat astigmatism permanently, since they allow correcting the asymmetry of the eye and significantly improve distance and near vision.
These lenses are manufactured with a custom curvature, according to the characteristics of the patient's eye, and provide great visual clarity. The placement of these intraocular lenses for astigmatism must be performed very rigorously for proper implantation.
