Myopia: an easily solved problem
One of the most common sight disorders is myopia or the inability to see distant objects because the light they emit focuses in front of the retina instead of inside it. The most common symptom is blurry vision, although those who suffer from myopia tend to half close their eyes to focus better, which can lead to headaches.

There are different types of myopia, which is partly hereditary and more frequent in women. It can appear at any time, yet up to 20% of 15 year-olds suffers from it. The most common way of correcting it is with glasses or contact lenses, the latter providing better all-round vision of the myopia is high because of the little distance between the eye and the correcting lens.

A radical manner of correcting the problem is surgery. A laser can remove part of the cornea�s tissue, thus modifying its curvature and significantly improving the sight. However, the patient�s myopia must have stabilised, otherwise it could return after surgery. Another technique is to place fixed lenses to flatten the cornea, comined with the use of glasses.

Lenses for tired vision
Tired vision or long-sightedness, meanwhile, is natural and inevitable deterioration of the eyes caused by aging and which consists of the loss of flexibility of the ocular lens. It usually appears at around 45 years of age and is associated with disorders such as anaemia and diabetes and habits such as having forced one�s near vision for too long a time. The most clear manifestation is the inability to focus one�s near vision and the need to keep books, etc, at a distance in order to see the letters clearly.

Bifocal lenses which enable you to alternate between near and far vision have traditionally been the most common treatment for long-sightedness. Progressive lenses are currently used, and these offer good intermediate vision but not so good lateral vision; they also require some time before users are comfortable with them. Long-sightedness can also be corrected with monovision and multifocal lenses and by surgically implanting intraocular lenses, an operation which is carried out under local anaesthetic. The problem is that the disorder will reappear after four or five years.

Surgery to remove cataracts
Another common problem associated with age is the appearance of cataracts, which make the eye�s crystalline lens lose its transparency. This can be corrected with glasses at first but the problem will gradually worsen until vision is completely lost. Cataracts are caused not only by aging, but also by the consumption of corticoids, diabetes or extreme myopia. The symptoms are blurry vision, problems seeing in intense light and the loss of colour perception. The only efficient treatment of the problem, which is degenerative, is surgery, which replaces the opaque crystalline lens with a clear one. The operation lasts about 15 minutes and is carried out under local anaesthetic.

Revisions to detect glaucoma
More serious and with less efficient treatment are glaucoma and age-related macular degeneration of the eye. The latter affects the centre of the retina, which is where the macula is found and usually appears in those aged 60 or over. The disease comes in two varieties: the so-called dry variety, which causes loss of central vision, and the wet variety, which is more acute and causes curved vision. To diagnose the disorder, in addition to sight tests, the back of the eye is examined and an angiogram is often carried out using fluorescein to ascertain the condition of the ocular blood vessels. Macular degeneration is difficult to prevent and treat. Vitamin and zinc supplements are usually employed and although loss of vision can be considerable over time,  y de zinc, total blindness is unlikely.

Glaucoma, meanwhile, is due to the increase of intraocular pressure, which irreversibly damages the fibres of the optical nerve. There are various types of glaucoma: chronic, which is the most frequent, acute and congenital. In general, the aged are the most susceptible, alongside diabetics, those with cardiovascular problems, and those with a family history of glaucoma. One of the inconveniences of the disorder is that it is completely asymptomatic until it takes hold, in that only periodical revisions of the back of the eye and of intraocular pressure can warn you whether it is likely to develop. Treatment is via eye drops that reduce intraocular pressure to prevent the condition from worsening or else laser intervention.