Vision, Loss Of: From 1 Different Sources
Inability to see. This may develop slowly or suddenly and may be temporary or permanent, depending on the cause. Vision loss may affect 1 or both eyes. It can cause complete blindness or may affect only peripheral, or only central, vision.
Progressive loss of visual clarity is common with advancing age and may be due to a number of disorders (see vision, disorders of).
Sudden loss of vision may be caused by disorders such as hyphaema, severe uveitis, vitreous haemorrhage, or retinal haemorrhage.
Optic neuritis can reduce vision in 1 eye.
Damage to the nerve connections between the eyes and brain, or to the visual area of the brain, can cause loss of peripheral vision and may be a result of embolism, ischaemia, tumour, inflammation, or injury.
See SQUINT.... double vision
Most vision tests examine a person’s sharpness of VISION (visual acuity) and often of the ?eld of vision (see VISION, FIELD OF). Refraction tests assess whether a person has an error that can be corrected with glasses such as ASTIGMATISM, HYPERMETROPIA or MYOPIA. Visual acuity is tested using a Snellen chart when the patient tries to read letters of di?ering standard sizes from 6 metres away. The optician will prescribe lenses to correct any defects detected by vision tests.... vision tests
The list of disorders resulting in poor or dim vision is huge. Disturbance of vision can result from an uncorrected refractive error, disease or injury of the cornea, iris, lens, vitreous, retina, choroid or sclera of the EYE. It may also result from disease or injury to the structures comprising the visual pathway from the retina to the occipital cortex (see VISION – Pathway of light from the eye to the brain) and from lesions of the structures around the eye – for example, swollen lids, drooping eyelids. (See EYE, DISORDERS OF.)... vision, disorders of
Refer: ALCOHOLISM, CATARACT, CONJUNCTIVITIS, DIABETES, ECLAMPSIA, GLAUCOMA, IRITIS, MIGRAINE, MULTIPLE SCLEROSIS, RETINITIS, SHOCK. ... blurred vision
Broadly speaking, vision is the ability to see.
Pathway of light from the eye to the brain Light enters the EYE by passing through the transparent cornea, then through the aqueous humour ?lling the anterior chamber. It then passes through the pupil, through the lens and the vitreous to reach the retina. In the retina, the rod and cone photoreceptors detect light and relay messages in the form of electrochemical impulses through the various layers of the retina to the nerve ?bres. The nerve ?bres carry messages via the optic nerve, optic chiasma, optic tract, lateral geniculate body and ?nally the optic radiations to the visual cortex.
Here in the visual cortex these messages are interpreted. It is therefore the visual cortex of the BRAIN that ‘sees’.
Visual acuity Two points will not be seen as two unless they are separated by a minimum distance. This distance is such that the objects are so far apart that the lines joining them to the eye enclose between them (subtend) an angle of at least one minute of a degree. This amount of separation allows the images of the two points to fall on two separate cones (if the light from two points falls on one cone, the two points would be seen as a single point). There are many tests of visual acuity. One of the more common is the Snellen test type. This is made up of many letters of di?erent size. By conventions the chart is placed 6 metres away from the patient. Someone able to see the lowest line at this distance has a visual acuity of 6/4. If they are only able to see the top letter they have 6/60 vision. ‘Normal’ vision is 6/6.
Colour vision ‘White light’ is made up of component colours. These can be separated by a prism, thereby producing a spectrum. The three cardinal colours are red, green, and blue; all other colours can be produced by a varying mixture of these three. Colour vision is a complex subject. The trichromat theory of colour vision suggests that there are three types of cones, each type sensitive to one of the cardinal colours. Colour perception is based on di?erential stimulation of these cone types. The opponent colour theory suggests that each cone type can generate signals of the opposite kind. Output from some cones can collaborate with the output from others or can inhibit the action of other cones. Colour perception results from these various complex interactions.
Defective colour vision may be hereditary or acquired, and can occur in the presence of normal visual acuity. HEREDITARY DEFECTIVE COLOUR VISION is more common in men (7 per cent of males) than women (0·5 per cent of females). Men are affected, but women convey the abnormal gene (see GENES) to their children. It occurs because one or more of the photopigments of the retina are abnormal, or the cones are damaged. Red-green colour defect is the most common. ACQUIRED DEFECTIVE COLOUR VISION is the result of disease of the cones or their connections in the retina, optic nerve or brain – for example, macular disease, optic neuritis. Col-our vision can be impaired but not lost as a result of corneal opaci?cation or cataract formation (see under EYE, DISORDERS OF).
TESTS OF COLOUR VISION These use specially designed numbers made of coloured dots surrounded by dots of confusing colour (e.g. plates).... vision
Loss of the peripheral visual field to the extent that only objects straight ahead can be seen clearly. Tunnel vision is most commonly caused by chronic glaucoma. Retinitis pigmentosa is another possible cause.... tunnel vision
If you’ve decided to go on a diet in order to lose weight, you have to be careful with what you drink and eat. Sodas and some juices are a definite no, and while you can drink water all the time, it might get a bit dull. If you want to try something different, and especially pleasant to the taste, tea’s the best choice. Find out more about the perfect teas for weight loss.
Benefits of tea for weight loss
If you drink your tea simple, without sugar, then you’ll enjoy a hot beverage with 0 calories. This at least prevents you from gaining weight.
However, based on the effect one type of tea may have on the digestive system, drinking tea can even help you lose weight. From green tea to oolong tea, each has its own health benefits which help you when you’re on a diet.
Types of tea for weight loss
First of all, green tea is perfect when you’re on a diet. Among its active constituents, green tea has catechin polyphenols, which is quite useful when you want to lose weight. Thanks to this, drinking green tea will increase thermogenesis (the amount of calories which are burned) and fat oxidation. You can drink 4-5 cups of tea a day.
Oolong tea is also helpful if you’re on a diet. It even has a stronger effect than green tea, by speeding up the body’s metabolism and promoting fat burning. If you include it in your diet, don’t drink more than two cups a day.
Peppermint tea is included on the list of teas you can drink while on a diet. Besides the fact that it promotes a good digestion, it helps you burn calories as it speeds up the digestive process.
Other teas that help you lose weight include star anise tea, rose petal tea, as well as various types of herbal teas.
Tea Steeping Time
Steeping time varies from one type of tea to another. If you use teabags, follow the instructions written on the box. If you use dried leaves to make your tea for weight loss, then here are a few steeping instructions.
If you’re drinking green tea, it’s best that you let it steep for about 3 minutes. Steeping time for oolong tea can vary from one minute to 5, based on how strong you want the tea’s flavor to be. And as for peppermint tea, you should let it steep for about 4-5 minutes.
Tips to sweeten your diet tea
If you want to sweeten your tea even when on a diet, you mustn’t use sugar or milk, even if you like those the best. While they won’t add weight, they also won’t help you lose it.
The best solution, in this case, is for you to use honey. Other things you can use to sweeten it are fruit juices (especially lemon juice) and stevia leaves. Based on your preferences and the taste of the tea you choose, you can even combine them.
Caffeine in tea and weight loss
The caffeine found in various types of tea also helps you lose weight. Caffeine acts as a stimulant; therefore it gives you more energy. The more energetic you feel, the more you’re bound to exercise in order to burn more fats. Also, as it acts as a stimulant, it can help reduce your appetite.
Caffeine might not be the only stimulant you’ll find in teas. Other stimulants include ginseng, taurine, and guarnine.
Side effects related to weight loss tea
People who know coffee doesn’t do them good should be careful with teas that contain caffeine. It can cause unpleasant side effects, such as insomnia, anxiety, headache, dizziness, irritability, blurred vision and skin rashes. When you combine your diet tea with a different alimentation and exercising, the side effects might become more unpleasant.
Also, make sure you check the amount of tea that’s recommended for drinking. You can have 4-5 cups of green tea per day, while in the case of oolong tea, it is advised that you drink two cups. The amount varies from one tea to another.
Now, drinking tea for weight loss sounds like a tempting idea. Considering how helpful tea can be when you’re trying to lose weight, make sure you pick one when you go on a diet.... drink tea for weight loss
Loss of appetite is usually temporary and due to an emotional upset or minor illness. Persistent loss of appetite may have a more serious underlying cause, such as chronic infection or cancer.... appetite, loss of
See amnesia.... memory, loss of
Inability to speak normally. Temporary partial loss of voice commonly results from straining of the muscles of the larynx through overuse of the voice or from inflammation of the vocal cords in laryngitis. Persistent or recurrent voice loss may be due to polyps on the vocal cords, thickening of the cords in hypothyroidism, or interference with the nerve supply to the larynx muscles due to cancer of the larynx, thyroid gland, or oesophagus. Total loss of voice is rare and is usually of psychological origin. (See also hoarseness; larynx, disorders of.)... voice, loss of
the ability to focus both eyes on an object at the same time, so that a person sees one image of the object he is looking at. It is not inborn, but acquired during the first few months of life. Binocular vision enables judgment of distance and perception of depth. See also stereoscopic vision.... binocular vision
see visual field.... field of vision
Alopecia. Baldness. Shedding of the hair in patches leaving glossy bald areas. It is normal to lose about one hundred hairs a day, but severe stress such as unemployment, divorce or death in a family may considerably increase hair loss. Losses of long-standing are seldom recovered.
Causes: hormone deficiency (Agnus Castus) in females, where it may be associated with failing thyroid or ovarian function. In such cases, other agents include: Helonias, Motherwort, Black Haw bark. Other causes may be pregnancy, the menopause, or simply discontinuing The Pill. Certain skin diseases predispose: ringworm (Thuja), eczema (Yellow Dock), from thyroid disorder (Kelp, Blue Flag root).
Exposure to some cosmetics, excessive sunlight, strong chemicals and treatment of cancer with cytotoxic drugs may interfere with nutrition of the hair follicles. To ensure a healthy scalp a correct mineral balance is essential calling for supplementation of the diet with vitamins, selenium, zinc and silica. Yellow Dock is believed to counter toxicity of chemicals; Pleurisy root opens the pores to promote sweat and action of surface capillaries.
Baldness sometimes happens suddenly; eye-lashes or beard may be affected. Though emotional stress and a run-down condition is a frequent cause, most cases are not permanent, returning to normal with adequate treatment.
Baldness of the eyebrows alerts us to a lowered function of the thyroid gland, being an early outward sign of myxoedema. A pony-tail hair style or the wearing of a crash helmet may cause what is known as traction alopecia. Heavy coffee drinkers invariably lose hair lustre.
Soviet Research favours silica-rich plants internally and as a lotion: Horsetail, Burdock, Nettles, Bamboo gum.
Growth of hair is assisted by improving surface circulation of the scalp which is beneficial for conveying nutrients to the hair roots and facilitating drainage. Herbal vasodilators stimulate hair follicle nutrition and encourage growth: Cayenne, Pleurisy root, Black Cohosh and Prickly Ash, taken internally. A convenient way of taking Cayenne is the use of a pepper-shaker at table.
Topical. Hair rinse. 2-3 times weekly. Infusion: equal parts Yarrow, Sage and Rosemary. 1oz (30g) to 1 pint (500ml) water. Simmer gently five minutes. Allow to cool. Strain before use.
Cider vinegar – minimal success reported.
Day lotion. Liquid Extract Jaborandi half an ounce; Tincture Cantharides half an ounce; Oil Jojoba to 4oz. Shake well before use.
Oily lotion. Equal parts Olive and Eucalyptus oils.
Bay Rhum Lotion. Oil of Bay 50 drops; Olive oil half an ounce; Rum (Jamaica or other) to 4oz. Shake well before use.
Oil Rosemary: rub into hair roots.
Russian Traditional. Castor oil half an ounce; Almond oil 1oz; Oil Geranium 15 drops; Vodka to 6oz. Rub into hair roots.
Aromatherapy. To 1oz Castor oil and 1oz Olive oil add, 10 drops each – Oils Neroli, Lavender and Rosemary.
Gentian plant extract. Japanese scalp massage with extract from roots to thicken thinning hair. Some success reported.
Supplements. B-vitamins, Kelp, Silicea Biochemic salt. Zinc. Low levels of iron and zinc can cause the condition.
Note: Studies show that male occipital baldness confers a risk of heart disease, being associated with a higher total cholesterol and diastolic blood pressure than men with a full head of hair. Frontal baldness has not been found to be associated with increased risk of coronary heart disease and myocardial infarct. “It seems prudent for bald men to be specially vigorous in controlling risk factors for such conditions.” (S.M. Lesko, Journal of the American Medical Association, Feb 24, 1993, 269: 998-1003) ... hair loss
n. no longer having some valued aspect of one’s life, such as a relationship, a job, or a home, that one has previously enjoyed. This may have health consequences: shock, disbelief, and emotional numbness may be followed by anger, guilt, anxiety, or profound sadness. Such emotions may lead to behavioural changes or symptoms that bring people to health care. Encouraging the patient to talk about the loss will require *empathy, sensitivity, and *judgment from the professional, both to obtain the history of the events and to provide helpful advice and direction to assist in adjustment. See also bereavement.... loss
(stereopsis) perception of the shape, depth, and distance of an object as a result of having *binocular vision. The brain receives two distinct images from the eyes, which it interprets as a single three-dimensional image.... stereoscopic vision
Any abnormality in colour vision that causes difficulty distinguishing between certain colours. Total absence of colour vision (monochromatism) is rare. The most common types of colour vision deficiency are reduced discrimination of red and green. Most cases of red and green colour vision deficiency are caused by defects in the light-sensitive cells in the retina. These defects are usually inherited, although occasionally defects are caused by retinal or optic nerve diseases or injury. The inherited defects tend to be sex-linked (see genetic disorders), which means that the majority of sufferers are male. A person with a severe green deficiency has difficulty distinguishing oranges, greens, browns, and pale reds. In severe red deficiency, all reds appear dull. A much rarer deficiency in which blue cannot be distinguished may be inherited or may be due to degeneration of the retina or optic nerve.... colour vision deficiency
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