Optical eye-problems explained

Myopia or near-sightedness (short-sightedness)

Myopia is a sight defect in the eye that allows good sight at close distancesclose, but at longe range the vision is blurred. Myopia is usually hereditary.

Optical describes myopia as the eye's refractive system is too strong in relation to the shaft length - that is the bening of the eye or lense is to strong or the eye is not long enough or both.

The error is compensated for with concave lenses - that is lenses that are thinnest in the middle and get thicker towards the peripheries.

Hyperopia or far-sightedness (long-sigtedness)

Hyperopia or far-sightedness is a common sight defect which entails that the eye is too short in relation to the refraction of the light in the rest position. It makes it difficult to see clearly at close range, but the visiion is clear at long ranges. The degree of hyperopia may vary.  Because the eye must make every effort to see clearly at close range, uncorrected hyperopi often leads to headaches.

By mild hyperopia, no correction is needed. By greater farsightedness one uses convexe lenses to correct - lenses that are thickest in the middle and get thinner towards the periphery.

There are fewer cases of hyperopia than the myopia. People tend to get far-sighed as they get older, or an originally myopia is gradually corrected by itself by the same process.

Common changes in sight during the lifetime

Young people tend to have normal vision aor be near-sighted. As one grow older, the aye develop such that an original near-sightedness is alleviated, the sight gets normal or one develop long-sightedness.

The eye lens also tend to get stiffer by age. That means that the sight is normal only at some specific ranges, but is blurred at both long ans short distances. This can be corrected for by using to pear of glasses or bi-focal glasses.

Astigmatism

Astigmatism is an optical error in the eye that give sa fuzzy, blurred vision. This is due to refractive error in the cornea (the cornea) or in the eye lens. The cornea can for example be eliptical or egg-shaped. By a lenticular (lens) astigmatism the curvature of the eye lens is not uniform in all planes.

The lack of spherical symmetry of the cornea or the lens makes the refraction of the light comming onto the retina different at different points. This usually destroy the focus in one plane, but the vision may be correctly focused in the plane at right angles to the first.

That is, if one looks at two lines that go in different directions, one or the other lines can be seen sharply according to how the head is held, or it is possible to focus one or the other line at certain distances.

Astigmatism means that it can be difficult to see fine detail. In some cases, for example, no vertically sthin objects, such as flag poles are seen as thicker blurred objects.

Often, astigmatism can be corrected with glasses, contact lenses or surgery. In an eyeglass or contact lens astigmatism can be corrected in that it includes an element of a cylinder lens in the glass. Such glasses are described by 3 parameters:

- A round, spherical refraction, measured in dioptre
- A cylindrical refraction, measured in dioptre.
- The cylinder axis, the angle specified in degrees.


About noni ( Morinda citrifolia) and noni juice

Botanical information

Noni is a shrub belonging to the family Rubiaceae growingt naturally in south east Asia but also spread by man to  the pacific islands. It is known by the names: Morinda citrifolia, Great morinda, Indian mulberry, Beach mulberry, Tahitian Noni, or since recently: Noni (from Hawaiian), Nono (in Tahitian), Mengkudu (from Malay), Nonu (in Tongan), and Ach (in Hindi)

The shrub is very adaptive to many surroundings, and is found both  in shady forrests and in sunny, sandy and rocky places. The shrub is capable of geowing in many types of soils, including vulcanic and salty soil types.

Noni gets small white flowers and produce  fruit all year round. The fruit is a oval composit  fruit 4-7 cm in size that smells pungently when ripen,  and is hence also known as cheese fruit or even vomit fruit. The noni fruit that contains many seeds is first green, then turns yellow, and then almost white as it ripens.

Production, preparation and trade

Fruit pulp powder in capsules was the first noni product coming into the market. The puøp powder was brought to the commercial market in Hawaii by Herbert Moniz of Herb's Herbs in 1992 after patenting a unique noni dehydrating method. (US patent 5288491) In 1995, David Marcus, of Hawaiian Herbal Blessings Inc., began marketing the first traditionally fermented noni juice from Maui, Hawaii.

About 300 companies are by mow marketing noni juice in a global market estimated at more than $2 billion annually. In 1996, Morinda Inc. (now Tahitian Noni International with headquarters in Orem, Utah) acquired noni from French Polynesia to manufacture juice, capsule and personal care products for the western market, achieving $1 billion in sales over the next seven years. Today, raw materials for noni juices on the world market mainly come from Polynesia but most manufacturers are in the United States.

Content of effective substances

Noni fruit pulp contains very much vitamin C,  and good amounts of vitamin B3 (Niacin), iron and potassium. However, the pasteurization process during production of noni juice destroys much of the natural vitamin content, but the content of iron and potassium remain.

Noni fruit contains many types of complex carbohydrates (oligo- and polysaccariodes). Many of these are boken down by bacteria in the colon yielding a complex mixture of short-chained fatty acids that may have health effects not yet fully investigated.

The smell and taste from noni originate from nonisides that are esters of alcohol and acids in the fruit.

Noni fruit contain scopolein that seem to have antimicrobic actions.

Noni contains beta-sitosterol that seem to have anticholesterol activities.

Noni contains the anthraquinone damnacanthal that seems to inhibit the action of HIV viral proteins.

Alkaloids of various kinds are present in noni. Alkaloids use to have a variety of medical effects, but these of the noni plant are not well investigated.

Many radiaceae plants contain glycosides – sugar-phenolic compounds including flavonoids such as rutin and asperulosidic acid. The content of these in noni is still not well investigated.

When noni juice is produced, it is heated to kill microbes in the original fruit. During such a process, effective substances can be destroyed. But new effective substances may at the same time be produced. Therefore medical effects of the commercial juice can be others than that of the natural fruit and juice.

Medical uses and effects

Noni has long been used as a traditional medical plant in many regions. The following uses are reported:

Against general weakness: Most parts of the plant us used as a general strengthening remedy in China, Samoa, Japan, and Tahiti.

Skin problems: Various perts of the plants are used as a general treatment of problems in the skin in China, Samoa, Japan, and Tahiti.

Throut and gum problems: Various perts of the plants are used as a general treatment of problems in the gum and throut in China, Samoa, Japan, and Tahiti.

Eye problems: Various perts of the plants are used as a general treatment of problems in theeye in China, Samoa, Japan, and Tahiti.

Stomach problems and constipation: One also uses various plant parts as treatment for constipation and stomach pain in China, Samoa, Japan, and Tahiti.

Against cough: Heated noni leaves applied to the chest are believed to relieve coughs In Malaysia.

For asthma: The fruit ias used against asthma in Indochina.

For lumbago: The fruit ias used against lumbago in Indochina.

For dysentery: The fruit ias used against dysentery in Indochina.

To heal broken bones: Unripe fruits are pounded, then mixed with salt and applied to cut or broken bones

Menstrual problems: The green fruit, leaves and the root/rhizome is to treat menstrual cramps and irregularities, among other symptoms.

Urinary problems: The root is used to treat urinary difficulties.

Sore and local infection rinsing: In Hawaii, ripe fruits are applied to draw out pus from an infected boil.

Against nausea: Heated noni leaves applied to the chest are believed to relieve nausea In Malaysia.

Against colic: Heated noni leaves applied to the chest are believed to relieve colic In Malaysia.

To nourish and strengthen the skin: Noni seed oil is used to apply on the skin to make the skin generally healthy. The linoleaic asid in the oil may be beneficial to the skin.

For acne and skin inflammation: Noni seed oil is used to apply on the skin to help heal acne and inflammatory processes in the skin. The linoleaic asid in the oil may be a working substance here.

Scientific research

Many scientific studies are going on to test the various health benefits attributed to noni. Some results has been abtained, but the results are not yet fully conclusive.

Many of these studies are concentrated on cancer, even though noni is not traditionally used against this disease.

In a study one observed reduced blood wessel growth ond vessel destruction in tumors of breast cancer transplanted from humans to mice. It is not yet decided if this effect will occur in breast cancer presented in humans.

Another study showed noni juice to inhibit formation of cancer cells in rats. lso noni has sown to reduce genetic damage in rats from cancerogenic agents.

Noni has shown to have anti-oxydative properties, especially against oxydative attacs from cancerogenic agents.

A picture showing the leaves and flowers of a noni plant. The picture has been obtained from wikipedia and is free to reuse:




Disclaimer: health information contained herein is provided for educational purposes only and is not intended to replace discussions with a healthcare provider. All decisions regarding patient care must be made with a healthcare provider, considering the unique characteristics of the patient.