Image may be NSFW.
Clik here to view.
Human life span, especially in developed countries, has grown considerably longer. Average life span is 74 years for a man and 78 years for a woman. Cataract (the clouding of eye lens) is a leading cause of blindness in the third world countries. Because of better medical care in developing countries, cataract is operated much more early (there is no waiting for the disease to develop), so the more serious consequences of the cataract, such as blindness, secondary glaucoma or deep eye inflammations, are considerably rarer. It is mostly caused due to aging, but can also appear at any other time as a consequence of diabetes, trauma, taking of certain medicaments (corticosteroids), radiation (x-ray, ultraviolet, infrared) or can be hereditary (congenital cataract). Cataract is present in 50% of people aged from 65 and 74, and in 70% of people older than 75. The development mechanism of cataract has not been explained in entirety. The main symptoms of the cataract are the decline in visual acuity and clouded vision.
Clouding of the eye lens is a natural process. As our eye lens grows old, our metabolism is becoming slower and gradually the minor damages are accumulated which are becoming increasingly more difficult to repair. That results in the densification (aggregation) of lens proteins which causes the clouding of the lens. By aging and increasing eye lens clouding, its hardness is also increased, that is, the cataract is becoming ripe. The classification of cataracts according to ripeness is usually performed by vision acuity test and an examination by an ophthalmologist by the help of a biomicroscope. Initial cataract is when the vision acuity is still relatively intact, that is, the patient sees at about 9-10%. It can pose a huge problem in those professions that require 100% vision acuity (for example, surgeon or an architect). As the cataract becomes riper, vision acuity is decreasing. At completely developed, ripe cataract, person sees only the light and the shape of objects. People with a medium ripe cataract, besides having decreased vision acuity, have symptoms such as glare due to the improper light reflection, which is especially noticeable during the sunny weather. Because of the densification of the core (nucleus) of eye lens, shortsightedness may appear which causes the improvement of near vision. In that case the person sees better at proximity when he or she takes his or her glasses off and believes that his or her sight has improved. Sadly, this phase of diopter improvement is only temporary and does not occur in all patients. As the clouding of the lens advances, the sight grows dim and the person sees as if through fog.
Except in the advanced age, cataract can appear even earlier. Congenital cataract is manifest at birth. It is extremely important to be diagnosed immediately so a surgery could be performed in order to prevent nearsightedness in child. If congenital cataract is of such nature that it completely prevents the access of light to the back of the eye (retina) where the image of the observed object is projected, the surgery should be performed as soon as possible. However, if the surgery isn’t performed in the first two to four weeks of life, the eye will not have good vision even after the surgery, as brain won’t develop the sight center connected to that eye.
Cataract can result from an injury or radiation. Trauma to the eye and an injury with a foreign object are the most common traumatic injuries which cause the clouding of eye lens. Sometimes such clouding does not develop completely but only partially, not posing a considerable disability and can be partially developed until advanced old age. In addition, different radiations can cause premature manifestation of cataract. Those are above all ultraviolet radiation and especially UV-a specter, then x-ray and infrared (heat) radiation. That is why it is recommended for safety goggles with 100% UV filter to be worn, because then the eye lenses are protected from premature aging and clouding. To the persons exposed to these kinds of radiation (glassblowers, radiologists, etc.) detailed examinations of eye lens are required at least once a year.
Complicated cataract is the name for clouding of eye lens that appears as a result of some other eye disease. Examples include glaucoma, uveitis (inflammation of uvea), ablation of retina, retinitis pigmentosa and so forth. In most cases the complicated cataract is to be found on one eye only. Treatment of complicated cataract is more complicated than ordinary cataract which results form aging.
Cataracts in people with diabetes (diabetes mellitus) are not complicated per se, but because of the disturbances in metabolism of diabetics, clouding of the eye lens appears earlier than in persons of the same age and gender who do not have diabetes. Besides that, in people with diabetes there is a connected tendency for changes in blood vessels of retina to form, which is called by a common name of diabetic retinopathy. The main requirement for a successful diagnosis, monitoring and treatment of changes in the back of the eye is the transparency of eye mediums, and therefore of eye lens as well. When the cataract has already advanced, laser applied in stopping the advance of diabetic retinopathy can no longer penetrate the inner part of the eye to reach the back of the eye. In addition, not even the ophthalmologist that is monitoring the advancement of diabetic retinopathy, due to clouding of the lens, can clearly see whether the retinopathy has advanced. Therefore such a cataract should be operated as soon as possible.