Both hyperopia and myopia, together with astigmatism, are what are called refractive errors. There are basically two surgical techniques to eliminate them:
Both techniques are completely safe and very fast. So much so that the same day of the intervention the patient can go home on his own feet, and the next day he will be able to start leading a practically normal life, without the need to wear glasses or contact lenses of any kind. The choice of one surgery or another depends mainly on the anatomical characteristics of the eye, which will be determined through a battery of diagnostic tests in our consultation.
Collagen lenses for the correction of refractive errors have been around for more than 20 years. It is one of the fastest, most reliable and safe techniques. In our center we are pioneers in the implantation of this type of lens; It was not in vain that Fernando Castanera MD was the first surgeon to implant collamer lenses in the country.
We could say that it is a kind of contact lens but that, instead of being placed on the cornea, it is permanently implanted inside the eye.
One of its main characteristics is that it is very flexible. This allows it to be folded, or rather rolled up, so that it can be inserted into the eye through a minimal incision. In addition, it is capable of correcting very high graduations, making it a great choice for patients with very high refractive errors.
The main advantage of the collagen lens is that it is a totally reversible technique, that is, during its implantation no structure is affected, so if it were necessary to remove or replace it, the eye would remain intact.
A whole battery of diagnostic tests are carried out to find out the patient's graduation and to know exactly what type of lens and what power it should have. It must be taken into account that this type of lens, in most cases, is ordered and manufactured specifically for each particular patient.
But among all the tests one of the most important is biometry. It is a test in which we can measure exactly the space between the iris and the lens. This measurement is extremely important because it will be decisive in determining whether or not the space is sufficient to house the collamer lens that will be located in this space.
A possible alternative could be laser intervention (LASIK or PRK) or continuing to wear glasses or contact lenses. In any case, in these cases it is always better to know the opinion of the ophthalmologist, who will surely be able to offer you the best alternative.
As we have said, the lens can be folded on itself. This allows it to be introduced into the eye through a minimal incision (2.2mm) and unfold inside.
The lens is positioned behind the iris and is held by the four haptics located on the edges.
The intervention does not last more than 10 minutes per eye since it is not necessary to alter any internal structure of the eye, simply the lens must be properly positioned behind the iris.
No, you will not feel any pain. The surgery is performed under local anesthesia and light sedation that allow the patient to be completely relaxed, in a kind of doze, and the eye completely anesthetized.
It is not possible, or rather it is not recommended, to perform the intervention with the patient completely asleep. This is because some collaboration is needed from the patient who has to look at a light. This will allow the eye to be fixed looking at one point in order to center and position the lens comfortably and quickly. Otherwise, the surgery could take longer than expected and the lens could be poorly positioned.
This is one of the best parts of undergoing surgery using this surgical technique and that is that patients begin to see in a more than acceptable way as soon as the intervention is finished. Many of them, still in the same operating room, are already surprised at how well they see without glasses.
In any case, keep in mind that full recovery may take a few days, not more than a week.
The suitability to be able to operate or not using this technique responds solely and exclusively to medical criteria. These will be based on the results obtained in the diagnostic tests that are carried out during the preoperative period.
Multiple tests are carried out, ranging from, obviously, knowing the exact graduation to be corrected, to the micrometric calculation of the thickness of the cornea. This calculation is precisely one of the most decisive factors when it comes to knowing if you are a good candidate or not to undergo the intervention. It must be taken into account that, as we will explain below, the action of the laser on the cornea implies the subtraction of part of the corneal tissue and that the higher the graduation, the more corneal tissue must be subtracted. Therefore, it is essential to know if our cornea is thick enough to support this subtraction. It should be noted that, if the tests indicate that we can go ahead with the intervention, the safety margin is always high enough to ensure that the cornea will withstand it perfectly.
In any case, these are non-invasive and rapid tests in which, mainly, the patient only has to look at a light and remain for a few seconds with the eye open.
If the thickness of the cornea is not enough to support the subtraction of tissue that our prescription requires, we only have two alternatives: continue using glasses or contact lenses or opt for collamer lens implantation surgery.
This technique consists of altering the anatomical characteristics of the cornea by modifying its curvature, and therefore its dioptric power, permanently. Remodeling is done in a very precise and controlled manner by vaporizing the corneal tissue. Some laser pulses polish the surface of the cornea with great accuracy until the refractive error is eliminated.
The intervention lasts no more than 10 minutes per eye and its effects are permanent and effective from the first moment, although vision may be altered during the first days due to the regeneration processes of the treated tissue.
No. Before the intervention, the patient is given a relaxant sublingually to provide a relaxed state. In addition, drops of anesthetic eye drops are instilled in the eye so that it is completely asleep before being manipulated.
The difference between the two is that in LASIK a fine lamella (150 microns) of the cornea is carved in order to apply the laser to the resulting surface. In the case of PRK, on the other hand, a very thin first layer (50 microns) is removed from the cornea called the epithelium and the laser is then applied.
The choice between one or another technique responds only to medical criteria.
This is precisely another of the differences between these two techniques: while recovery with LASIK is more immediate (the next day a more than acceptable vision is achieved), with PRK it takes between 7 and 15 days to stabilize vision. . This is because the epithelium must completely regenerate and during this time vision can fluctuate until it reaches its optimal state.
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