Defects of eye and its correction

Myopia: (nearsightedness) This is a defect of vision in which far objects appear blurred but near objects are seen clearly. The image is focused in front of the retina rather than on it usually because the eyeball is too long or the refractive power of the eye?s lens too strong. Myopia can be corrected by wearing glasses/contacts with concave lenses these help to focus the image on the retina.

Hyperopia: (farsightedness) This is a defect of vision in which there is difficulty with near vision but far objects can be seen easily. The image is focused behind the retina rather than upon it. This occurs when the eyeball is too short or the refractive power of the lens is too weak. Hyperopia can be corrected by wearing glasses/contacts that contain convex lenses.

Astigmatism: This defect is when the light rays do not all come to a single focal point on the retina, instead some focus on the retina and some focus in front of or behind it. This is usually caused by a non-uniform curvature of the cornea. A typical symptom of astigmatism is if you are looking at a pattern of lines placed at various angles and the lines running in one direction appear sharp whilst those in other directions appear blurred. Astigmatism can usually be corrected by using a special spherical cylindrical lens; this is placed in the out-of-focus axis.

Cancer

known medically as a malignant neoplasm, is a broad group of diseases involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invading nearby parts of the body. The cancer may also spread to more distant parts of the body through the lymphatic system or bloodstream. Not all tumors are cancerous; benign tumors do not invade neighboring tissues and do not spread throughout the body. There are over 200 different known cancers that affect humans.

Classification

Carcinoma: Cancers derived from epithelial cells. This group includes many of the most common cancers, particularly in the aged, and include nearly all those developing in the breast, prostate, lung, pancreas, and colon.

Sarcoma: Cancers arising from connective tissue (i.e. bone, cartilage, fat, nerve), each of which develop from cells originating in mesenchymal cells outside the bone marrow.

Lymphoma and leukemia: These two classes of cancer arise from hematopoietic (blood-forming) cells that leave the marrow and tend to mature in the lymph nodes and blood, respectively. Leukemia is the most common type of cancer in children accounting for about 30%.[94]

Germ cell tumor: Cancers derived from pluripotent cells, most often presenting in the testicle or the ovary (seminoma and dysgerminoma, respectively).

Blastoma: Cancers derived from immature "precursor" cells or embryonic tissue. Blastomas are more common in children than in older adults.

Signs and symptoms

When cancer begins it invariably produces no symptoms with signs and symptoms only appearing as the mass continues to grow or ulcerates. The findings that result depend on the type and location of the cancer. Few symptoms are specific, with many of them also frequently occurring in individuals who have other conditions. Cancer is the new "great imitator". Thus it is not uncommon for people diagnosed with cancer to have been treated for other diseases to which it was assumed their symptoms were due.

Glasgow Coma Scale

The Glasgow Coma Scale or GCS is a neurological scale that aims to give a reliable, objective way of recording the conscious state of a person for initial as well as subsequent assessment. A patient is assessed against the criteria of the scale, and the resulting points give a patient score between 3 (indicating deep unconsciousness) and either 14 (original scale) or 15 (the more widely used modified or revised scale).

GCS was initially used to assess level of consciousness after head injury, and the scale is now used by first aid, EMS, nurses and doctors as being applicable to all acute medical and trauma patients. In hospitals it is also used in monitoring chronic patients in intensive care.

Eye response (E)

There are four grades starting with the most severe:

No eye opening

Eye opening in response to pain stimulus. (a peripheral pain stimulus, such as squeezing the lunula area of the patient's fingernail is more effective than a central stimulus such as a trapezius squeeze, due to a grimacing effect).[1]

Eye opening to speech. (Not to be confused with the awakening of a sleeping person; such patients receive a score of 4, not 3.)

Eyes opening spontaneously

Verbal response (V)

There are five grades starting with the most severe:

No verbal response

Incomprehensible sounds. (Moaning but no words.)

Inappropriate words. (Random or exclamatory articulated speech, but no conversational exchange)

Confused. (The patient responds to questions coherently but there is some disorientation and confusion.)

Oriented. (Patient responds coherently and appropriately to questions such as the patient?s name and age, where they are and why, the year, month, etc.)

Motor response (M)

There are six grades:

No motor response

Extension to pain (extensor posturing: abduction of arm, external rotation of shoulder, supination of forearm, extension of wrist, decerebrate response)

Abnormal flexion to pain (flexor posturing: adduction of arm, internal rotation of shoulder, pronation of forearm, flexion of wrist, decorticate response)

Flexion/Withdrawal to pain (flexion of elbow, supination of forearm, flexion of wrist when supra-orbital pressure applied ; pulls part of body away when nailbed pinched)

Localizes to pain. (Purposeful movements towards painful stimuli; e.g., hand crosses mid-line and gets above clavicle when supra-orbital pressure applied.)

Obeys commands. (The patient does simple things as asked.)

Dialysis

In medicine dialysis is a process for removing waste and excess water from the blood, and is used primarily as an artificial replacement for lost kidney function in people with renal failure. Dialysis may be used for those with an acute disturbance in kidney function (acute kidney injury, previously acute renal failure), or progressive but chronically worsening kidney function?a state known as chronic kidney disease stage 5 (previously chronic renal failure or end-stage renal disease). The latter form may develop over months or years, but in contrast to acute kidney injury is not usually reversible, and dialysis is regarded as a "holding measure" until a renal transplant can be performed, or sometimes as the only supportive measure in those for whom a transplant would be inappropriate.

The kidneys have important roles in maintaining health. When healthy, the kidneys maintain the body's internal equilibrium of water and minerals (sodium, potassium, chloride, calcium, phosphorus, magnesium, sulfate). The acidic metabolism end-products that the body cannot get rid of via respiration are also excreted through the kidneys. The kidneys also function as a part of the endocrine system, producing erythropoietin and calcitriol. Erythropoietin is involved in the production of red blood cells and calcitriol plays a role in bone formation.[3] Dialysis is an imperfect treatment to replace kidney function because it does not correct the compromised endocrine functions of the kidney. Dialysis treatments replace some of these functions through diffusion (waste removal) and ultrafiltration (fluid removal).

Suicide

Suicide (Latin suicidium, from sui caedere, "to kill oneself") is the act of intentionally causing one's own death. Suicide is often committed out of despair, the cause of which is frequently attributed to a mental disorder such as depression, bipolar disorder, schizophrenia, borderline personality disorder,alcoholism, or drug abuse. Stress factors such as financial difficulties or troubles with interpersonal relationships often play a role. Efforts to prevent suicide include limiting access to firearms, treating mental illness and drug misuse, and improving economic development.

The most commonly used method of suicide varies by country and is partly related to availability. Common methods include: hanging, pesticide poisoning, and firearms. Around 800,000 to a million people die by suicide every year, making it the 10th leading cause of death worldwide. Rates are higher in men than in women, with males three to four times more likely to kill themselves than females. There are an estimated 10 to 20 million non-fatal attempted suicides every year. Attempts are more common in young people and females.

Views on suicide have been influenced by broad existential themes such as religion, honor, and the meaning of life. The Abrahamic religions traditionally consider suicide an offense towards God due to the belief in the sanctity of life. During the samurai era in Japan, seppuku was respected as a means of atonement for failure or as a form of protest. Sati, a now outlawed East Indian practice, expected the widow to immolate herself on her husband's funeral pyre, either willingly or under pressure from the family and society.

Suicide and attempted suicide, while previously criminally punishable, is no longer in most Western countries. It remains a criminal offense in many countries. In the 20th and 21st centuries, suicide in the form of self-immolation has been used as a medium of protest, and kamikaze and suicide bombings have been used as a military or terrorist tactic.

Date: 2016-06-12; view: 205