Ophthalmology of high specialty
Presbyopia occurs naturally as the eyes age and the structure of the crystalline responsible for focusing the images changes. This produces images that are focused behind the retina instead of being focused on it.
Myopia occurs in eyes in which images are focused incorrectly in front of the retina instead of directly on it. The retina is the light-sensitive tissue in the back of the eye that is responsible for processing images.
Astigmatism occurs when the cornea (the outer transparent layer of the eye) does not have the same curvature in all areas. The light coming from objects that enters the eye is focused on more than one spot on the retina, causing blurred and distorted vision.
Farsightedness (poor close up vision) is a refractive error, which means that the eye does not refract or bend light properly and images are not clearly focused. With farsightedness, distant objects are usually seen clearly, but those that are near are blurred.
People experience farsightedness in different ways. Some people may not have any problem with their vision, especially when they are children. Other people with considerable farsightedness may have blurred vision at any distance, near or far.
Keratoconus is a disease of the cornea which causes poor vision gradually. During the evolution of keratoconus our cornea takes on an irregular conical shape due to the alteration of its internal structure.
The internal structure of the cornea contains collagen fibers. Collagen is a protein of elongated shape, and the alteration of this protein in the interior of our cornea is the main cause of the development of keratoconus.
This is a lesion that starts on the ocular conjunctiva in the form of a small growth of fleshy tissue that is called pterygium if it moves over the cornea. It starts with small grayish opacities on the cornea near the nasal limbus. The lesion grows over the opacities and covers the cornea in a triangular shape, causing diminished vision.
The uvea contains many blood vessels (veins, arteries and capillaries) that carry blood to the inside and outside of the eye. Because the uvea nourishes many important parts of the eye (such as the retina), an inflammation of the uvea can damage your vision.
There are various kinds of uveitis, which are defined according to the parts of the eye where they occur.
Glaucoma is a degenerative disease caused by increased pressure within the eye (ocular tension). The eye contains a fluid similar to water in its interior which is continually renewed, but if the drainage system fails, intraocular pressure increases which can damage the optic nerve.