The retina is the innermost layer of the eyeball and its mission is to capture the images initially focused by the cornea and lens. Once images are captured by a number of specialized cells to it, called photoreceptors, are sent through nerve fibers to the optic nerve, which contains about one million of them, and finally to brain areas for managing the vision .
Due to its characteristics, the retina can be considered as part of the brain, and thus participates in a number of neurological diseases of all types: congenital, degenerative, metabolic, etc..
We will focus on perhaps the most common diseases that typically affect the retina.
The most common type is the one produced by the appearance of a tear in the peripheral retina, through which fluid can penetrate and take off a bag of retina, which can progress to affect the richest area in photoreceptors, called the macula, or even cause detachment of the retina.
The origin of these tears can be traumatic, for traction in the “collapse” of the vitreous, (common from the 50 to the emergence of so-called “floaters”) or from debilitating retinal degenerations , more generally in myopic three diopters.
Retinal detachment may or may not be preceded by the display flashes and / or “floaters”, finally taking an area without vision (vision curtain) which can be getting bigger.
The treatment is a relative urgency and broadly consists in causing the tear seal, the fluid drain and a number of methods to apply the detached retina to the underlying layers.
It is important if you notice flashes or floaters flare, go to the ophthalmologist, because if the tear is detected before producing the release, you can “weld” and avoid laser. In high myopic is also very important to the periodic review of the peripheral retina even when asymptomatic.
In the development of diabetes, both type 1 as2, are a series of changes in the vessels of the body. This deterioration in the vessels of the retina, can seriously damage the visual function if not diagnosed early and appropriate treatment instituted.
The so-called diabetic retinopathy, usually initiated, depending on the patient’s metabolic control, after approximately 10 years of onset of the disease, and involves the loss of cells (pericytes) that stabilize the structure of the capillaries. Thus, phenomena occur initially “herniated” referred to in the capillary microaneurysms, and increased permeability of these salts with accumulation of cholesterol in appearance and bright yellowish white (hard exudates). Breakage of microaneurysms may also produce microhemorrhages from a number of different shapes and sizes. This stage is called Background Diabetic Retinopathy.
In the course of the disease, occlusion occur capillary phenomena, true microinfarcts, whose representation is the appearance of the retina in less bright white spots that the above described known soft exudates. This stage is called the Pre-Proliferative Diabetic Retinopathy.
Microinfarcts presage these further complications because they produce no perfusion areas in the retina, which stimulate the formation of humoral factors known as VEGF, which aims to stimulate new vessel formation (neovascularization) that provide blood flow to ischemic areas. This attempt, far from improving the situation, the worse, as these new vessels are fragile and easily bleed profusely or retract and fibrosed causing bleeding, which can fill the back of the eye cavity blood and prevent vision for months, and even detached retinal shrinkage. This stage is called proliferative diabetic retinopathy, the proliferation of these vessels.
As for the diagnosis of diabetic retinopathy, is vital early diagnosis, so we suggest an annual assessment of the fundus to detect early lesions. If injuries occur and it is useful to a test called fluorescein angiography, which involves observing the behavior of a dye injected into a vein, performing a series of serial photography, we indicate areas of leakage or poorly perfused retinal areas ( ischemic).
The treatment consists in initially applying laser heal we vanishing points (microaneurysm) and / or eliminate us sacrifice ischemic areas to prevent secretion of vascular proliferative factors and the occurrence of the devastating neovessels. There are also complex surgical techniques to treat major complications such as bleeding in the vitreous and tractional retinal detachments. (Vitrectomy).
Age-Related (AMD): In a significant percentage of the population over 60 years, there are degenerative changes in the central area of the retina. This area, called the macula, (“spot” for the accumulation of yellow pigments) is responsible for 90% of the vision that we used (central), and the color vision, by the presence of the “cone” specialized photoreceptors in color vision.
The origin of AMD is multifactorial, in addition to age, affecting factors such as poor diet and antioxidant carotenoids, snuff, sun exposure, etc..
Lesions are seen are of two types, basically: Areas of atrophy characterizing the most common type of AMD, called “dry AMD”. There is a slow and progressive loss of central vision. Such degeneration is not, at present, treatment, but may slow the progression of antioxidant supplementation.
Another type is the so called wet ARMD, which consists in forming globular whitish lesions and composite materials “waste” from the retina, called “drusen”. These lesions eventually produce sometimes rupture of a layer of the retina, which stimulates the formation of a neovascular membranes ascending from the lower layers (choroid), toward the retina. As in diabetic retinopathy, these neovessels may ooze or bleed, causing sudden visual loss, with the presence of distortion of objects (metamorphopsia) that reproduce the “bumps” of the retina swollen or black spots in the visual field called scotomas.
In terms of diagnosis, we also used fluorescein angiography and, in recent years called optical coherence tomography, which offers a sectional images of the retina similar to a scanner.
Treatment involves repeated injection into the eyeball of substances which inhibit the VEGF causes, such as diabetes, neovascular formations.