ASTIGMATISM - Fernández-Vega Ophthalmological Institute
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Another of the defects of refraction is astigmatism. In normal vision, the cornea has a similar curvature across its surface, that is, symmetrical. What differentiates it from other defects such as hyperopia is the alteration of the curvature and therefore, if there is any alteration or unevenness in its curvature, we are faced with an astigmatic defect.


In a cornea with astigmatism, the meridians are different; one is more curved and the other is flatter.  Astigmatism may be isolated or associated with myopia or hyperopia.

Patients have blurred and distorted vision both from far and near. The way to correct it is by toric lenses or with laser refractive surgery.

What is the level of astigmatism in the Spanish population?

The prevalence of significant astigmatism (equal to or greater than 1.5 dioptres) in Spain is around 25% of the population, making it the third most common visual problem among Spaniards behind myopia and presbyopia, also known as eyestrain.


And among people who undergo cataract surgery?

40% have a dioptre or more of astigmatism and 20% one and half dioptre or more, an amount that, as we have said, begins to be clinically significant and needs to be corrected.


How does astigmatism affect vision? Why is it important to correct it?

This defect of testing depends fundamentally on the cornea and affects both near and far sightedness.  It is for this reason that it is important to correct it and thus improve visual quality in every way.


It is currently possible to correct astigmatism during cataract surgery. What are the advantages?

Indeed, thanks to new technologies, the correction of astigmatism during cataract surgery is possible today. This translates into a clear benefit for patients, since in a single surgical procedure we can improve their quantity and quality of vision, as well as diminish or eliminate their dependence on glasses.


What is the operation like?

Astigmatism is determined by the morphology of the cornea, which may be more curved in one meridian than in another. The problem can be corrected by corneal incisions in order to modify its curvature, or by the use of the so-called toric intraocular lenses. On the other hand, the digital systems of intraoperative evaluation of astigmatism, recently added to our operating rooms, are helping us to improve our results.


What role do intraocular lenses play here?

A fundamental role, since in addition to correcting the decrease in vision caused by the cataract, they can be given the appropriate graduation to correct myopia, hyperopia, astigmatism and presbyopia. Lenses are customized to solve the individual problem of each patient Toric lenses, which specifically correct astigmatism, save us the need to act on the cornea with the laser, thus preserving its integrity.


Does the patient fully regain vision?

In general, the entire testing is normally corrected and vision completely recovered if there is no other associated eye problem.


How is it done? What technologies and materials come into play?

Astigmatism is determined by the morphology of the cornea, which may be more curved in one meridian than in another, causing the images to focus on the retina in a distorted way, affecting near and farsighted vision. This can be corrected by performing corneal incisions capable of modifying this curvature or by the use of toric intraocular lenses which include the correction of astigmatism.


What have the latest technologies contributed to this type of interventions?

The latest technologies have helped us to be more effective and accurate in the diagnosis and treatment of these graduation defects. We can practically correct any degree of astigmatism with a high success rate.


What is the situation of astigmatism in the Spanish population? And among those affected by cataracts?

The incidence of significant astigmatism (equal to or greater than 1.5 dioptres) in Spain is around 25% of the population, making it one of the most common ocular complaints along with myopia and presbyopia. Since it is not a disease that progresses over time, its prevalence does not differ in those patients with cataracts.

Is it a complicated operation for the patient?

Not at all – the correction of astigmatism does not imply a greater surgical risk for the patient.

Is it possible to correct astigmatism during a cataract operation?

Like other graduation defects such as myopia and hyperopia, astigmatism can be corrected effectively during cataract surgery.

Is it usual for patients to ask about this type of correction of refractive defects?

It is a common issue, as patients are becoming more aware of their eye problems and are interested in the origin of astigmatism and how to correct it.