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Retina (DMAE)

La retina, la capa más interna del globo ocular,es una membrana transparente compuesta de numerosas células fotosensibles encargadas de recibir los estímulos luminosos y transmitirlos a través de sus terminales nerviosas al cerebro. Existen 2 tipos de células fotoreceptoras: los conos y los bastones.

Los conos funcionan mejor con luz diurna y están especializados en la visión de los colores. Los bastones son más numerosos y funcionan con la luz nocturna o la oscuridad. Los conos son más abundantes en el centro de la retina, llamada también mácula o fóvea. Los bastones se encuentran en la periferia. Cuando conos y bastones son estimulados por la luz, se generan impulsos que son transmitidos a través de las fibras nerviosas de los mismos y que confluyen para formar el nervio óptico.

La retina se nutre por vasos arteriales retinianos y por capilares de la coroides, que es la capa vascularizada más externa de la retina.

  • The vitreous

    The vitreous is a transparent, gelatinous substance which occupies the inner part of the eye, providing support to the retina. It has no nutritive vessels, since it would lose its transparency. Over the years, the vitreous may lose its consistency and separate from the retina, causing deposits which are perceived as threads or spots that move with the eyes; these are more visible in bright light or when looking at light-colored walls or objects. These deposits are referred to as myodesopsia, "floaters", or "mouches volantes". Usually they do not indicate any kind of disease, nor do they represent any risk to one's vision; however, if they are perceived, one must rule out the presence of any coexisting pathology in the retina or vitreous.

  • What are the main problems of the retina?

    The retina can be affected by:

    • Many general diseases, such as diabetes or ocular hypertension (high eye pressure)
    • Inflammations or infections
    • Vascular irregularities such as thrombosis or embolisms
    • detachments which produce loss of vision in one part of the field of vision, or in its entirety
    • Degeneration, its most frequent and important instance being age-related macular degeneration
  • How to diagnose these diseases?

    Diagnosis of all these diseases is important in order to provide early treatment. For this purpose we have many techniques and instruments at our disposal, most notably: retinoscopy (observation of the retina and vitreous with or without dilating the pupil), fluorescein angiography, computerized campimetry, and for some time now, optical coherence tomography – a very high-precision, latest-generation instrument for studying the retina.

  • Irregularities in the layers of the retina which nourish and provide oxygen to the pigment epithelium are the cause of age-related macular degeneration (AMD). This can be either dry or wet (exudative) AMD, the latter being characterized by the appearance of blood vessels, which can give rise to hemorrhaging and accumulation of liquid between layers of the retina.

    With AMD, the patient will report irregularity in the central vision of the affected eye, image distortion or deformity.In such cases, the Amsler test offers a simple method for monitoring symptoms.

    Recent years have brought to light the so-called antiangiogenic substances. When injected into the inner eye, they often make it possible to control loss of vision or even to improve it, in some cases of exudative (wet) age-related macular degeneration.

    With the help of the latest technology in ophthalmological exploration, we are able to detect retinopathies in the earliest stages of macular degeneration, when the patient may not report any kind of symptoms. This is the case with Optical Coherence Tomography (OCT).

  • RetinaRetina

    This technique examines retinal layers through images, visualizing a cross-section of the desired area of the retina. The slightest irregularity among the layers (as in cases of AMD) is projected, measured, compared and monitored, thanks to the different visual perspectives offered by the software. Even 3-D imaging of the retina can be obtained.

    A database of population studies is incorporated, giving us automatic comparisons of the thickness of retinal ganglion fibers which lead to the optic nerve, and in this way assess their normality. This is especially useful in the case of patients with glaucoma, both as a support to diagnosis as well as in monitoring its development over time.

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