Refractive and presbyopia surgery

The eye can suffer from different pathologies and one type of them is called ametropia, which causes a defect in the focus of the image on the retina, which prevents the images from being processed and perceived properly, resulting in a decrease in visual acuity.

The main ametropias are:

• Myopia, when the eyeball is very long or the cornea is very curved and the image is formed in front of the retina.
• Hyperopia, when the eyeball is very short or the cornea is slightly curved and the image is formed behind the retina.
• Astigmatism, when the cornea is not homogeneously curved and the image is blurred or distorted.

In general, these types of defects are corrected with or contact lenses, but today there are various surgical techniques that allow these alterations to be corrected in both eyes in the same intervention. Obviously, like any surgical intervention, it has its risks, but in general the results are usually excellent. Before the intervention, a study is carried out to assess the corneal surface and thickness, as well as the integrity of the retina. In case of myopia, the ideal is to have surgery before the age of forty, while in hyperopia it is advisable to wait until that age because presbyopia or tired eyesight can modify the visual capacity of patients over that age.

Lasik

One of the most used techniques is laser surgery called LASIK. It is a technique that intervenes on the eye with local anesthesia and consists of raising a small window in the cornea by means of a cut and applying the laser in the depth of the cornea to mold it and correct the defect. In the case of myopia, its curvature is reduced, in hyperopia said curvature is increased and in astigmatism the surface is molded to make it all regular and homogeneous. After applying the laser, the corneal window is closed again and it heals on its own in a matter of a few minutes without the need for stitches.

During the intervention, which lasts between 30 and 60 seconds per eye, pressure is felt on the eyeball and nothing is seen, but no pain should be felt. In more than 90% of cases, a perfect vision is achieved, but this always depends on the degree of the pathology: the higher the number of diopters, the more difficult a complete resolution is, and can be corrected up to about 15 diopters, which can be that the patient also requires the use of glasses or contact lenses after the intervention. Sometimes a second corrective intervention may be necessary if the degree of ametropia is very high.

The LASIK technique allows a quick recovery, in about 24 hours, it does not cause healing problems by acting on the deep planes of the cornea, since it is the superficial layers that can become opaque. After the intervention, drops will be needed for a few days to prevent infections and counteract dry eyes, as well as sleep with a protective patch to prevent the patient from unconsciously touching the eye.

The side effects of the intervention can be blurred vision, itching, dryness, decreased night vision, flashes, sensitivity to light or redness of the eye, but they are all temporary. During the first months, there may be an overcorrection of visual defects, with which the patient does not see correctly, but this effect usually disappears in 3-6 months. In severe cases, 1% of patients may have a loss of vision compared to the previous one, which most of the time recovers in about 7 months.

Other surgical methods

Beyond the LASIK technique there are other surgical methods, some based on different laser applications and others through the use of intraocular lenses (IOL).

Photorefractive keratectomy (PRK) is a technique similar to LASIK, but unlike LASIK, it is applied to the surface of the cornea. Under local anesthesia, an upper layer of the cornea is opened before applying the laser and after closing without sutures, an external soft lens is placed for 4 days, allowing the lesion to heal. This technique is a better option if the cornea is thin or if the patient has previously undergone LASIK.

LASEK or laser-assisted epithelial keratectomy is a method that, using a trephine, makes an opening in an extremely superficial layer of the cornea and then laser is applied to the surface of the cornea, as in PRK, after which a close again and a protective lens is also placed for 4 days. It is an ideal method if the cornea is very thin or has many asymmetries. As in the PRK technique, when acting on the surface, the eyeball is less weakened and the results of the intervention are more stable, but on the contrary, there is a greater risk of alterations in healing (1-3% of cases) when acting on superficial layers of the cornea and the postoperative period is more complex, since there may be pain, recovery can take between 2 and 4 weeks and the use of eye drops is required for about four months.

The EpiLASIK technique consists of applying the PRK after lifting a very thin layer of the corneal surface after which it is placed back in place or simply removed, so a protective lens must be placed again for about 4 days after the intervention.

Conductive keratoplasty is based on the use of radiofrequency, which consists of applying heat to the periphery of the cornea in such a way that the peripheral size is reduced and the central curvature is increased, which is a good technique to correct hyperopia. It is applied only to the non-dominant eye, so that the other eye allows a better vision from a distance.

IOLs are useful in patients with many diopters. The lenses can be placed either in front of the lens or it can be replaced by a new lens, as is done in cataract procedures. It is a good option in severe hyperopia or if there is a beginning of cataracts.

The aforementioned presbyopia or eyestrain consists of an aging of the crystalline lens, the intraocular lens, which by losing flexibility causes the ability to focus closely to decrease. It is a condition that usually develops between 40 and 45 years of age and is generally corrected with progressive or multifocal glasses.

And for presbyopia ...

Likewise, as for ametropia, presbyopia can be intervened using various techniques such as those previously described. PrebiLASIK is a laser treatment that shapes the cornea so that the center can be seen well up close while the periphery allows good vision in the medium and long distance. The intervention lasts about 5 minutes, the postoperative period is somewhat annoying but good vision is obtained in about 48 hours.

Other techniques to correct presbyopia are the INTRACOR technique using femtosecond laser, with a painless postoperative period of less than 24 hours, the conductive keratoplasty described above and a postoperative procedure similar to that of INTRACOR, or the implantation of an IOL, either on the lens. or replacing it.

The decision to undergo surgery must be made by the patient, always guided and advised by the ophthalmologist and with realistic expectations of the level of correction of visual capacity in each case. Obviously, if the patient is not bothered by wearing glasses or contact lenses, it is not necessary at all to go through an operating room unnecessarily, but in people with many diopters these interventions can greatly improve their quality of life.

With MAPFRE Health Insurance we offer you, at special prices, laser techniques for the correction of myopia, hyperopia, astigmatism and presbyopia. It includes the consultation, the means of diagnosis and surgery. If you want more information

WHAT YOU SHOULD KNOW

• Myopia, hyperopia and astigmatism are usually corrected with glasses or contact lenses, but also with various surgical techniques.
• They have very good results in general and one of the most used is LASIK.
• In these cases, it is advisable to operate before the age of 40, but in presbyopia it is better to do it afterwards as it can modify the visual capacity at that age.

For more information about MAPFRE health insurance