Causes for Vision Loss Essay Paper

Causes for Vision Loss Essay Paper

People from childhood learn the world through vision, thanks to vision a person perceives surroundings. That is why it is very important to preserve vision in good condition and take care of it all life long. However, there are situations when it may be impaired.Causes for Vision Loss Essay Paper

The main causes of visual impairment include spinal problems, contamination of the body, psychological factors and various diseases (Subramanian, 2014). Diseases cause violations in various systems of the body, one of the possible stages is blurred vision. Most dangerous eye diseases are of infectious venereal nature. Bacteria and viruses primarily influence nervous system. Impaired vision is a direct consequence of the problems in visual nerve centers.

This research paper examines the five causes of vision loss: Cataracts, Glaucoma, Diabetic Retinopathy, Refractive Error, and Age related macular degeneration.

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Cataract

Cataract is one of the most common eye diseases among the elderly. Cataract is an ophthalmic disease associated with clouding of the eye’s lens and causing different degrees of visual disturbances up to the total loss of vision.

In some cases, the disease can develop under the influence of external factors, such as under the influence of radiation or as a result of certain diseases, particularly diabetes. The majority of cataracts is a natural result of aging. Physically, clouding of the lens is caused by the denaturation of the protein, which is part of the organ.

Cataracts occur at any age. There are different types of cataract: congenital cataract, traumatic, complicated, radiation, cataracts caused by common diseases of the organism. But the most common is age (senile) cataract, which occurs in people over 50 years old. Senile cataract exceeds 90 % of all cases. At the age of 52-62 years 5% of people, and 75-85 years 92% have the initial stage of cataract (Hildreth, 2009).Causes for Vision Loss Essay Paper

According to the World Health Organization, cataract affects about 17 million people, mostly after the age of 60 years. In 70-80 years, cataract is present in 260 men and 460 women in 1000, and after 80 years – almost everyone. Statistics show that cataract has become a cause of blindness in 20 million people in the world (Bethune, 2013).

Causes of Cataract

Factors contributing to the development of cataracts include:

• genetic predisposition;
• eye injury (chemical, mechanical, contusion injury);
• various eye diseases (including glaucoma, high myopia);
• endocrine disorders (metabolic disorder, diabetes, vitamin deficiency);
• radiation, microwave and ultraviolet radiation;
• long-term use of certain drugs;
• increased radiation;
• unfavorable environmental conditions;
• toxic poisoning (naphthalene, thallium, mercury, ergot);
• smoking (Allen, 2005).

Treatment of cataract

Treatment of the initial stages of age-related cataracts is sometimes based on the use of various drugs, mainly in the form of eye drops. It is known that the use of these drugs doesn’t lead to resorption of already formed haze, but can only slow progression. The only effective cure for cataracts is surgery with removal of the opaque lens and replacing it with an artificial intraocular lens.

The most modern and least traumatic way to remove cataracts today is ultrasonic phacoemulsification with implantation of an artificial intraocular lens. Such an operation is to replace the muddy afflicted cataract lens with artificial intraocular lens. Local drip anesthesia used during surgery is easily tolerated by patients of all ages and doesn’t put a strain on the cardiovascular system. This procedure is characterized by a small incision and a “gold” standard in cataract eye surgery. Improved vision is observed in 95 % of patients. Besides, it does not require the full maturation of cataract and can be applied during the initial stages of its development. Phacoemulsification has no age restrictions, it can be used both in infancy and in the elderly (Bethune, 2013).

Phacoemulsification is so safe that it can be operated as an outpatient. The effectiveness of this method is confirmed by the fact that the vision of the patient due to the implantation of an artificial lens is starting to recover already on the operating table.

Glaucoma

There are eye diseases that develop imperceptibly, but eventually lead to a complete loss of vision. Classic example is glaucoma. Glaucoma is a large group of eye diseases characterized by continuous or periodic increase in intraocular pressure and subsequent development of typical defects of visual field, reduced vision and optic atrophy.Causes for Vision Loss Essay Paper

If the eye pressure is not reduced to normal in the right time, optic nerve dies, which leads to irreversible blindness. There are two main forms of glaucoma: open-angle and angle-closure. In addition, there are congenital glaucoma, juvenile, and various forms of secondary glaucoma, including those related to developmental abnormalities of the eye.

According to statistics, 14-15 % of all blind people around the globe have lost their vision for glaucoma. In general, people over 40 years old suffer from glaucoma, however, young people can have youth glaucoma, and even infants – congenital glaucoma (Angunawela, 2013). Also according to the World Health Organization, glaucoma is the main disease that, in the absence of timely treatment, causes irreversible blindness. More than 5 million people are blind from glaucoma, which is 13.5% of all blind people in the world (James, 2014).

Causes of glaucoma

A healthy eye has a constantly maintained certain pressure (18-22 mm Hg. Tbsp.) due to a balance of inflow and outflow of liquid. Patients with glaucoma have impaired circulation of liquid. Fluid accumulates and the intraocular pressure starts to rise. The optic nerve and other structures of the eye are experiencing increased stress, disrupting the blood supply of the eye. As a result of optic nerve atrophy, visual signals stop coming to the brain. Patients begin to see worse, peripheral vision is disturbed, resulting in limited visibility range; and eventually blindness can occur.

Intraocular pressure increases in the cases where the intraocular fluid excretion is disturbed. There are three main types of glaucoma: primary, secondary and congenital. The most frequent type is primary glaucoma. It appears in earlier seemingly healthy eyes for no apparent reason, as a rule, in people over 40 years (Angunawela, 2013).

There are risk factors that influence the onset and progression of glaucomatous process. Local factor is myopic refraction (myopia) and common factors are: age over 60-65 years, heredity, diabetes, hypotension, diseases of thyroid and plywood system, etc.

Congenital glaucoma may be due to abnormal embryonic development of the eye – dysgenesis of the angle of the anterior chamber, as well as a consequence of other eye diseases (tumors, inflammation, trauma) before or during birth.

Secondary glaucoma is a consequence of the concrete preceding eye diseases. Its causes may be:

• inflammatory diseases of the eye: keratitis, uveitis, scleritis;
• dislocation (shift) of the lens;
• cataracts;
• degenerative eye disease: progressive atrophy of the iris, consequences of hemophthalmia, etc.;
• contusions, burns, eye injuries;
• surgery on the eyes;
• swelling of the eye (Ali, 2012).

Glaucoma is an irreversible disease. Therefore, it is very important to begin treatment in time. Ophthalmologists pay attention to the possibility sudden loss of vision as a result of an acute attack of glaucoma.

Glaucoma treatment

Nerve damage and vision loss in glaucoma can not be stopped, but there are treatments that can slow or stop the progression of the disease. Treatment can make the normal intraocular pressure, and prevent or arrest further development of nerve damage and blindness.

In glaucoma patients require a systematic and long-term care, always under a doctor’s supervision. Typically, treatment begins with drug use: eye drops reduce intraocular pressure; pills improve nutrition of the optic nerve and retina. Medications are mainly aimed at reducing intraocular pressure. But it is important to remember that the drops do not restore fluid balance in the eye, but only artificially support it. Drug treatment rarely produces the desired result, so often surgical treatment is used.

Another method of treatment is a laser surgery. The operation consists in creating a new path for the outflow of intraocular fluid to reduce intraocular pressure. It should be made as early as possible, it will provide persistence of vision in patients with glaucoma. This technique of surgery is called non-penetrating deep sclerectomy. Major advantage of surgery is that it is carried out without opening the eyeball. This eliminates the possibility of infection, significantly reduces the risk of complications during surgery.Causes for Vision Loss Essay Paper

One of the new treatments for glaucoma is the treatment of cannabis. Since glaucoma leads to an increase in intraocular pressure and may cause the loss of vision, the patient is prescribed with drugs that lower intraocular pressure. Ophthalmologic research has shown that medical marijuana reduces tearing and reduces pressure inside the eye. Experiments, conducted by the University of California, have confirmed the beneficial effects of cannabis for the treatment of this disease.

Diabetic retinopathy 

Diabetic retinopathy is one of the most serious complications of diabetes, manifestation of diabetic microangiopathy, which affects the blood vessels to the retina of the eyeball, observed in 90% of patients with diabetes mellitus. Term diabetic retinopathy indicates pathological changes of the retina and its vessels, arising as a consequence of the general vascular lesions in diabetes. Capillaries of the retina get the main damage. The lesion may be manifested by the emergence of little bumps on the small blood vessels of the retina (microaneurysms), minor bleeding in the retina.

It is well known that diabetes is one of the most common diseases. According to recent statistics, this pathology was detected in 5% of world population, and diabetic retinopathy ranks first among the causes of blindness and low vision. Age of onset of diabetes and its duration influence the development of diabetic retinopathy. In patients with diabetes detected before 30 years, retinopathy frequency increases from 50% after 10-12 years of the onset of diabetes, to 75% or more after 20 years. If diabetes is diagnosed at a later age, retinopathy can develop much faster and is observed in 75-80% of cases within 7-8 years (Drakatos, 2012).

Damaged blood vessels can leak blood. Swelling (edema) is formed in the retina. Later there may occur increased formation of new blood vessels (neovascularization) and multiplication of connective tissue, and this condition can result in total blindness. Blindness in patients with diabetes occurs 25 times more often than among those who do not suffer from this disease (Cheung, 2010).

Causes of visual loss in diabetic retinopathy lie in the fact that newly formed vessels are very fragile. They have thin walls, consisting of a single layer of cells that grow rapidly, different turbulent plasma extravasation, increased fragility. This fragility leads to bleeding inside the eye of varying severity. Not extensive hemorrhage into the vitreous or retina resolve spontaneously, and massive processes in the eye cavity (hemophthalmus) lead to the development of irreversible fibrotic proliferation (proliferation of tissue) in the vitreous, leading to complete blindness.

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Treatment of diabetic retinopathy

The most widely used method for the treatment of diabetic retinopathy and macular edema is a laser therapy made on an outpatient basis. The essence of this method is the following:

• destroy hypoxic zone of the retina, which is the source of growth of newly formed vessels;
• increase the direct supply of oxygen to the retina of the choroid;
• implement thermal coagulation of newly formed vessels.

For the treatment of proliferative or preproliferative DR, laser coagulates are applied throughout the retina, except central departments (panretinal photocoagulation). This way, newly formed vessels are subjected to focal laser irradiation. This surgical technique is particularly effective in the early stages of the disease, preventing blindness in almost 100% of cases. In advanced cases, its effectiveness is greatly reduced. In diabetic macular edema, laser action is subjected to central parts of the retina. The duration of therapeutic effect is largely dependent on the system status of the patient (Rao, 2012).Causes for Vision Loss Essay Paper

Vitrectomy – surgery is indicated for extensive intraocular hemorrhage or advanced stage of proliferative retinopathy. Its essence lies in the surgical removal of the eye cavity, blood clots, opaque parts of the vitreous fibrovascular strands from the surface of the retina. They remove (if possible) back hyaloid membrane located between the vitreous and the retina, which plays a role in the progression of proliferative retinopathy.

Drug therapy and DR hemophthalmia is probably the most controversial part of modern ophthalmology. Medications include various antioxidants and means of reducing the permeability of blood vessels, improving metabolic processes in the tissues of the eye.

When expressed hemorrhages, patients may use intraocular administration of enzyme preparations. However, at the moment there are no drugs able to cope with the advanced stages of diabetic retinopathy.

Refractive Error (Ametropia)

The most common cause of visual impairment among the world’s population now is ametropia – refractive error of the eye. These are: nearsightedness, farsightedness, astigmatism, anisometropia and often accompanying – amblyopia and strabismus. World Health Organization included it to the Program for the elimination of avoidable blindness and low vision “Vision 2020” as the most common cause of visual impairment in the world along with such serious problems of blindness, as cataract, childhood blindness and others (Naidoo, 2012).

Ametropia is a change of refractive power of the human eye, the result of which is that rear eye focus misses retina while relaxing accommodative muscles. Human eye is a complex optic system. With a clear vision, light rays reflected from objects pass through the cornea and lens and focus on the retina. Refraction in this case is proportional, i.e. emmetropic. Elasticity of the lens can change its curvature surfaces, always changing the refractive power of the eye, the light rays are focused on the retina (Stambolian, 2013). Refractive power of eye is measured in Diopters (D). Ametropia includes:

1) nearsightedness (myopia);

2) farsightedness (hyperopia);

3) astigmatism as well as “age” farsightedness (presbyopia).

Treatment of refractive error

Refractive disorders of eye structure are an irreversible process. It is impossible to increase or reduce eye to normal size. This means that all degrees of refractive error can not be treated. They can only be corrected. Of course, there are exceptions where you can get rid of defective vision surgically.

Types of refractive error correction:

1. Spectacle correction
2. Contact correction
3. Surgical correction.

Selection of correction type depends on individual correction tolerance and symptoms of maladjustment, and on the willingness of the patient and professional requirements. Often, when ametropia begins to rapidly grow, on-time operation will stop the disease process, such as curbing the growth of the eyeball in progressive myopia, or scleroplasty, or the use of laser photocoagulation (observed with rupture of retina) (Tahhan, 2013).Causes for Vision Loss Essay Paper

Age related macular degeneration

Age related macular degeneration (AMD) is a disease that affects the central section of the retina – the macula, and impairs central vision Chakravarthy, 2010). This is a common cause of reduced vision in people over 60 years. Since only the central vision is affected, people rarely go blind from the disease. However, patients with AMD have difficulties to read, drive or do other work that requires good vision.

The majority of patients (approximately 90% of cases) have a so-called dry form of AMD (Cheung, 2013). Its cause is unknown. There is a slow destruction of light-sensitive cells in the macula. Decreasing number of working cells deteriorates central vision. The wet form of AMD occurs in approximately 10% of patients with macular degeneration. It arises when newly formed vessels begin to grow under the retina. These vessels are fragile, leaking blood and fluid. This results in rapid damage to the macula, which can lead to rapid loss of central vision.

AMD risk increases with age. In aged over 75 years, the risk rises to almost 30%. Other risk factors are smoking, high blood cholesterol, family history (Lim, 2012).

 Treatment of Age related macular degeneration

In most cases, dry macular degeneration does not need treatment. Sometimes, there can be used a threshold or low intensity laser therapy, the essence of which is to go through the course of treatment with moderate doses of laser radiation to remove the drusen (yellowish sediment).

Recent developments in the treatment of wet macular degeneration led to the creation of Ranibizumab (Lucentis), which is inserted into the eye cavity and inhibits the activity and the growth of new vessels and subretinal neovascular membranes, leading not only to stabilizing but also to improving vision. Typically, it takes 5 injections per year, and is treated for about 2 years. Improved vision in most patients occurs after the first injection. Its use is possible both in wet macular degeneration and diabetic retinopathy, as well as in combination with photodynamic therapy.Causes for Vision Loss Essay Paper

Conclusion

Eyes are given to man to see the world, they are a way of knowing volume, color and stereoscopic images. Persistence of vision is one of the most important conditions of human activity in elderly and senile age. The basis of age-related changes of eyes lies in the same physical, chemical and biological processes, which influence other human organ. Manifestations of physiological aging are inevitable. But it is possible to delay the onset of some of them.

In modern life, due to adverse environmental and social conditions, stress and other effects, the senescence processes of body, including the eyes, may occur earlier, even in individuals who have not attained the elderly.

Human body is a complete system, where everything is interconnected, and often origins of eye diseases lie in other organs and systems. For example, diabetes cause severe complications of the eye; metabolic disorders can lead to clouding of the lens (cataract); diseases of the cardiovascular system affect the blood supply of the retina and optic nerve; diseases of the nervous, cardiovascular and endocrine systems can lead to glaucoma. Consequently, people should monitor the health of the entire body for the prevention of eye diseases.Causes for Vision Loss Essay Paper