Cornea | IOA Madrid
To treat corneal problems there are several types of surgery. Most of the corneal conditions that require surgery treatment can be encompassed within one of these techniques:
Corneal transplantation is performed when this loses its transparency or due to deformities that affect its optical characteristics (keratoconus, post-surgery ectasias, etc)
It is performed with local anaesthetic and as an outpatient surgery.
There are several types of corneal transplantation.
- Fully penetrating. Consists of the replacement of all the corneal layers.
- Lamellar. Only the damaged part is transplanted.
- Anterior, indicated for pathologies that affect the corneal stroma: Keratoconus, corneal scars, post-refractive surgery ectasisas, corneal dystrophies, etc.
- Endothelial, indicated for pathologies affecting the endothelium, the most frequent is Fuchs endothelial dystrophies or guttata cornea or the post-surgery corneal decompensation.
Frequently asked questions: :
- What is the risk of rejection? The risk of ejection in corneal transplants is low, as one of the characteristics of the cornea is that it does not have blood vessels in normal conditions, so the possibility that the body recognises the foreign tissue is very low. Likewise, it depends on the pathology that conditioned the transplant, the keratoconus being the one with less possibility of rejection.
- What symptoms does a rejection cause? The symptoms are a sharp and progressive decrease of the eyesight, redness of the eye and photophobia (sensitivity to light). In the event of any of these symptoms, you must visit the ophthalmologist.
- Can it be treated? The treatment consists of frequently applying eye drops with corticosteroids, and also often orally at high doses for short periods of time. Depending on the degree of rejection, the transplant can be recovered or not; in this last case a new transplant would be needed to recover the eyesight.
Intracorneal rings are transparent segments that are placed in the thickness of the cornea at approximately 6 mm from the visual axis. They have the aim of strengthening the corneal structure and of regularising it. With this we prevent the progression of diseases such as keratoconus and we improve the eyesight quality of patients, because as the shape of the cornea decreases astigmatisms and the high degree optical aberrations that can not be corrected with glasses or contact lenses.
Intracorneal ring surgery is performed with topical anaesthetic (drops), it lasts for 10 to 15 minutes and the patient can go home after it. Miranza IOA Madrid has a femtosecond laser to perform the tunnel where the ring is going to be inserted, which makes the risk of intraoperative complications almost null.
Surgery with intracorneal rings is a reversible surgery, so that if the refractive effect is not as desired, the rings can be removed and the cornea goes back to its initial condition.
To correct the residual prescription after surgery with intracorneal rings we can use glasses, contact lenses or intraocular lenses.
Keratoconus is the alteration of the collagen fibres that make up the stroma (the thickest part of the cornea), which are weaker than normal, so the cornea deforms forwards and adopts the shape of a cone instead of a sphere.
Outstanding among the symptoms it causes is the increase of astigmatism and a progressive loss of vision. It usually occurs in adolescence and develops over the years. To improve the vision the use of contact lenses is usually necessary, that do not stop the development of the cone, and are only an optical treatment that provide a better vision.
Keratoconus is diagnosed by performing a topography.
The treatments to stop the development depend on the stage of the pathology.
- Crosslinking. Indicated for very initial stages in which there is a progression of the cone seen by means of topographies. It consists in applying ultraviolet radiation on the cornea to harden the collagen fibres and stop the development.
- Intracorneal rings The rings are placed in the thickness of the cornea and act strengthening the weakened area. They enable shaping the cornea and improving the patient's vision quality.
- Corneal Transplantation. For very advanced stages. Today, lamellar transplants can be done to replace the diseased part of the cornea, which lowers the risk of rejection.
Phototherapeutic keratectomy (PTK) consists in “polishing” the cornea with Excimer laser.
It is indicated in pathologies that affect the most superficial part of the cornea. Scars after adenoviral conjunctivitis, recurrent episodes of corneal pain (recurrent keratalgia), either post-traumatic or in patients with basement membrane dystrophy.
The surgery is performed with local topical anaesthetic (drops) and last between 10 and 15 minutes. It is normal to feel discomforts in the immediate post-surgery yet these are usually mild. The vision may not be perfect until up to 7 and 15 days after the operation and may vary during the day. As a consequence of the treatment, the patient's prescription may change and he/she may require glasses or new surgery with a refractive purpose.
The cornea is a tissue that must be transparent to enable the passage of light to the retina. There are many reasons why the cornea may lose its transparency: congenital or acquired infections, traumatisms or corneal dystrophies.
Depending on the location and the density of the scar, this can produce loss of vision in different degrees.
The diagnosis is made by means of an ophthalmologic examination. Regarding its treatment, in the cases in which the loss of vision is scarce, nothing has to be done, only be under observation. In the case that the loss of vision is greater and affects the quality of life of the patient, the treatment will depend on the depth of the scar: If they are very superficial a "polishing" with laser can be considered (it is what is called PTK or phototherapeutic keratectomy). In cases of deeper scars, the treatment consists of transplanting the area affected.
Keratitis is an inflammation of the cornea. The causes are multiple, and include:
- Dryness. Generally produces superficial keratitis that cure without leaving after-effects. It is manifested by the feeling of a foreign object, redness and in severe cases loss of vision if it affects the visual axis. They improve with lubricants, although they can be recurrent and in some occasions may require more specific treatments (tear plugs, autologous serum, master formulas, etc,).
- Viral infections. The most frequent is the keratitis due to simple herpes, which leaves a scar and is one of the most frequent causes of corneal transplant in our means. They are recurrent and early diagnose and treatment is essential.
- Bacterial infections, by fungus or amoeba. They are more frequent in patients wearing contact lenses or in cases of traumatisms or prior erosion. They are very serious infections that require the use of fortified antibiotic eye drops and they usually leave corneal scars that limit the eyesight.
- Other causes. Due to exposure, in patients with incomplete palpebral closure due to caustics, actinic due to sun exposure (typical of skiers or welders without goggles), etc.
Fuch's endothelial dystrophy or Guttata cornea
Patients with guttata cornea have less endothelial cells than normal. Endothelial cells have the function of dehydrating the cornea to maintain its transparency, so the cornea of these patients slowly fills with water causing oedema.
The first symptoms appear in the morning with blurred vision, that improves during throughout the day. In more advanced stages the blurred vision is maintained throughout the day, as if there was fog and halos around lights. In terminal stages pain may appear due to the formation of bullae or blisters that may break when blinking.
The diagnostic is clinical, by observing the cornea. In initial stages the endothelial cells can be recounted.
The treatment is surgical, by transplanting endothelial cells.
uring the acute episode of pain, this disease can be treated with topical medication or therapeutic contact lenses. The treatment with Laser is definitive (Phototherapeutic Keratectomy or PTK). As when we have a skin wound which hasn't healed well it has to be cleaned and left to heal again, the same happens with this treatment. The laser polishes the surface of the cornea leaving it smooth; when the epithelium grows it creates new, stronger adhesions to the cornea, reducing the probability of the erosion to reappear.
The treatment is not at all painful, much less than the episodes of acute eye pain.