Categories
Ailmemts & Remedies

Retinitis pigmentosa

Definition:
Retinitis pigmentosa(RP) is an eye disease in which there is damage to the retinaretina. The retina is the layer of tissue at the back of the inner eye that converts light images to nerve signals and sends them to the brain.

CLICK & SEE 
It is a group of genetic eye conditions that leads to incurable blindness. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades. Many people with RP do not become legally blind until their 40s or 50s and retain some sight all their lives. Others go completely blind from RP, in some cases as early as childhood. Progression of RP is different in each case.

CLICK & SEE

RP is a type of progressive retinal dystrophy, a group of inherited disorders in which abnormalities of the photoreceptors (rods and cones) or the retinal pigment epithelium (RPE) of the retina lead to progressive visual loss. Affected individuals first experience defective dark adaptation or nyctalopia (night blindness), followed by reduction of the peripheral visual field (known as tunnel vision) and, sometimes, loss of central vision late in the course of the disease.

Symptoms:
Mottling of the retinal pigment epithelium with black bone-spicule pigmentation is typically indicative (or pathognomonic) of retinitis pigmentosa. Other ocular features include waxy pallor of the optic nerve head, attenuation (thinning) of the retinal vessels, cellophane maculopathy, cystic macular edema and posterior subcapsular cataract.

Symptoms often first appear in childhood, but severe vision problems do not usually develop until early adulthood.

•Decreased vision at night or in low light
•Loss of side (peripheral) vision, causing “tunnel vision”
•Loss of centralcentral vision (in advanced cases)

Causes:
It is a group of genetic eye conditions that leads to incurable blindness. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades. Many people with RP do not become legally blind until their 40s or 50s and retain some sight all their lives. Others go completely blind from RP, in some cases as early as childhood. Progression of RP is different in each case.

RP is a type of progressive retinal dystrophy, a group of inherited disorders in which abnormalities of the photoreceptors (rods and cones) or the retinal pigment epithelium (RPE) of the retina lead to progressive visual loss. Affected individuals first experience defective dark adaptation or nyctalopia (night blindness), followed by reduction of the peripheral visual field (known as tunnel vision) and, sometimes, loss of central vision late in the course of the disease.

Retinitis pigmentosa can run in families. The disorder can be caused by a number of genetic defects.

The cells controlling night vision (rods) are most likely to be affected. However, in some cases, retinal cone cells are damaged the most. The main sign of the disease is the presence of dark deposits in the retina.

The main risk factor is a family history of retinitis pigmentosa. It is an uncommon condition affecting about 1 in 4,000 people in the United States.

Diagnosis:-
The diagnosis of retinitis pigmentosa relies upon documentation of progressive loss in photoreceptor cell function by electroretinography (ERG) and visual field testing.

The mode of inheritance of RP is determined by family history. At least 35 different genes or loci are known to cause “nonsyndromic RP” (RP that is not the result of another disease or part of a wider syndrome).

DNA testing is available on a clinical basis for:

*RLBP1 (autosomal recessive, Bothnia type RP)
*RP1 (autosomal dominant, RP1)
*RHO (autosomal dominant, RP4)
*RDS (autosomal dominant, RP7)
*PRPF8 (autosomal dominant, RP13)
*PRPF3 (autosomal dominant, RP18)
*CRB1 (autosomal recessive, RP12)
*ABCA4 (autosomal recessive, RP19)
*RPE65 (autosomal recessive, RP20)

For all other genes, molecular genetic testing is available on a research basis only.

RP can be inherited in an autosomal dominant, autosomal recessive, or X-linked manner. X-linked RP can be either recessive, affecting primarily only males, or dominant, affecting both males and females, although males are usually more mildly affected. Some digenic (controlled by two genes) and mitochondrial forms have also been described.

Tests:-
Tests to evaluate the retina:

•Color vision
•Examination of the retina by ophthalmoscopyophthalmoscopy after the pupils have been dilated
•Fluorescein angiographyFluorescein angiography
•Intraocular pressureIntraocular pressure
•Measurement of the electrical activity in the retina (electroretinogramelectroretinogram)
•Pupil reflex response
•Refraction testRefraction test
•Retinal photographyRetinal photography
•Side vision test (visual field test)
•Slit lamp examinationSlit lamp examination
•Visual acuityVisual acuity

Genetic counseling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing.

Associations:
Retinitis pigmentosa is seen in a variety of diseases, so the differential of this sign alone, is broad.

*RP combined with deafness (congenital or progressive) is called Usher syndrome.
*RP combined with opthalmoplegia, dysphagia, ataxia, and cardiac conduction defects is seen in the mitochondrial DNA disorder Kearns-Sayre syndrome (aka Ragged Red Fiber Myopathy)
*RP combined with retardation, peripheral neuropathy, acanthotic (spiked) RBCs, ataxia, steatorrhea, is absence of VLDL is seen in abetalipoproteinemia.

Other conditions include neurosyphilis, toxoplasmosis(Emedicine “Retinitis Pigmentosa”), abetalipoproteinemia, and Refsum’s disease.

Genetics
Retinitis pigmentosa (RP) is one of the most common forms of inherited retinal degeneration. This disorder is characterized by the progressive loss of photoreceptor cells and may eventually lead to blindness.

There are multiple genes that, when mutated, can cause the Retinitis pigmentosa phenotype. In 1989, a mutation of the gene for rhodopsin, a pigment that plays an essential part in the visual transduction cascade enabling vision in low-light conditions, was identified. Since then, more than 100 mutations have been found in this gene, accounting for 15% of all types of retinal degeneration. Most of those mutations are missense mutations and inherited mostly in a dominant manner.

The rhodopsin gene encodes a principal protein of photoreceptor outer segments. Studies show that mutations in this gene are responsible for approximately 25% of autosomal dominant forms of RP.

Mutations in four pre-mRNA splicing factors are known to cause autosomal dominant retinitis pigmentosa. These are PRPF3, PRPF8, PRPF31 and PAP1. These factors are ubiquitously expressed and it is still a puzzle as to why defects in a ubiquitous factor should only cause disease in the retina.

Up to 150 mutations have been reported to date in the opsin gene associated with the RP since the Pro23His mutation in the intradiscal domain of the protein was first reported in 1990. These mutations are found throughout the opsin gene and are distributed along the three domains of the protein (the intradiscal, transmembrane, and cytoplasmic domains). One of the main biochemical causes of RP in the case of rhodopsin mutations is protein misfolding, and molecular chaperones have also been involved in RP. It was found that the mutation of codon 23 in the rhodopsin gene, in which proline is changed to histidine, accounts for the largest fraction of rhodopsin mutations in the United States. Several other studies have reported other mutations which also correlate with the disease. These mutations include Thr58Arg, Pro347Leu, Pro347Ser, as well as deletion of Ile-255. In 2000, a rare mutation in codon 23 was reported causing autosomal dominant retinitis pigmentosa, in which proline changed to alanine. However, this study showed that the retinal dystrophy associated with this mutation was characteristically mild in presentation and course. Furthermore, there was greater preservation in electroretinography amplitudes than the more prevalent Pro23His mutation.

Treatment:
Although incurable the progression of the disease can be reduced by taking some measures.
Wearing sunglasses to protect the retina from ultraviolet light may help preserve vision.

Some studies have suggested that treatment with antioxidants (such as high doses of vitamin A palmitate) may slow the disease.
Recent studies have shown that proper vitamin A supplementation can postpone blindness by up to 10 years (by reducing the 10% loss pa to 8.3% pa). However, taking high doses of vitamin A can cause serious liver problems. The benefit of treatment has to be weighed against risks to the liver.

Several clinical trials are in progress to investigate new treatments for retinitis pigmentosa, including the omega-3 fatty acid, DHA.

Microchip implants that go inside the retina and act like a microscopic video camera are in the early stages of development for treating blindness associated with this and other serious eye conditions.

It can help to see a low-vision specialist, who can help you adapt to vision loss. Make regular visits to an eye care specialist, who can detect cataractscataracts or retinal swelling — both of which can be treated.

Research on possible treatments:
Future treatments may involve retinal transplants, artificial retinal implants, gene therapy, stem cells, nutritional supplements, and/or drug therapies.

2006: Stem cells: UK Researchers working with mice, transplanted mouse stem cells which were at an advanced stage of development, and already programmed to develop into photoreceptor cells, into mice that had been genetically induced to mimic the human conditions of retinitis pigmentosa and age-related macular degeneration. These photoreceptors developed and made the necessary neural connections to the animal’s retinal nerve cells, a key step in the restoration of sight. Previously it was believed that the mature retina has no regenerative ability. This research may in the future lead to using transplants in humans to relieve blindness.

2008: Scientists at the Osaka Bioscience Institute have identified a protein, named Pikachurin, which they believe could lead to a treatment for retinitis pigmentosa.

2010: A possible gene therapy seems to work in mice.

2010:R-Tech Ueno(Japanese Medicine manufacture enterprise )Completes Phase II Clinical Study on Ophthalmic Solution UF-021 (Product Name Ocuseva (TM)) on Retinitis Pigmentosa.

Prognosis:
The disorder will continue to progress, although slowly. Complete blindness is uncommon.

Prevention:
Genetic counseling and testing may help determine whether your children are at risk for this disease.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.

Resources:
http://en.wikipedia.org/wiki/Retinitis_pigmentosa
http://www.nlm.nih.gov/medlineplus/ency/article/001029.htm

http://www.rwjuh.edu/health_information/adult_eye_retin.html

http://www.nlm.nih.gov/medlineplus/ency/imagepages/1094.htm

Enhanced by Zemanta
Categories
News on Health & Science

Bionic Eye ‘Blindness Cure Hope’

[amazon_link asins=’B000PGRBGA,B000RBE5TE,B004S5AC10,B005172AYQ,B01FNJP3X6,B001MA60PQ,B002RGOENO,B01KA3EBH4,B0016P2U6A’ template=’ProductCarousel’ store=’finmeacur-20′ marketplace=’US’ link_id=’3e2d1b1c-78d5-11e7-abae-09b227b78a00′]

A ‘bionic eye‘ may hold the key to returning sight to people left blind by a hereditary disease, experts believe.

………………………..click & see

………………………………The treatment is being tested in clinical trials

A team at London’s Moorfields Eye Hospital have carried out the treatment on the UK’s first patients as part of a clinical study into the therapy.

The artificial eye, connected to a camera on a pair of glasses, has been developed by US firm Second Sight.

It said the technique may be able to restore a basic level of vision, but experts warned it was still early days.

The trial aims to help people who have been made blind through retinitis pigmentosa, a group of inherited eye diseases that affects the retina.

The disease progresses over a number of years, normally after people have been diagnosed when they are children.

It is estimated between 20,000 to 25,000 are affected in the UK.

It is not known whether the treatment has helped the two patients to see and any success is only likely to be in the form of light and dark outlines, but doctors are optimistic.

Lyndon da Cruz, the eye surgeon who carried out the operations last week, said the treatment was “exciting”.

“The devices were implanted successfully in both patients and they are recovering well from the operations.”

Other patients across Europe and the US have also been involved in the trial.

Electronic

The bionic eye, known as Argus II, works via the camera which transmits a wireless signal to an ultra-thin electronic receiver and electrode panel that are implanted in the eye and attached to the retina.

The electrodes stimulate the remaining retinal nerves allowing a signal to be passed along the optic nerve to the brain.

David Head, chief executive of the British Retinitis Pigmentosa Society, said: “This treatment is very exciting, but it is still early days.

“There is currently no treatment for patients so this device and research into stem cells therapies offers the best hope.”

“This treatment is very exciting, but it is still early days” …. says David Head, of the British Retinitis Pigmentosa Society

CLICK TO SEE ALSO :->
Sight-saving injection approved

Woman ‘denied sight-save drugs’

NHS criticised on blindness cure

Man in NHS battle ‘to save sight’

Second Sight

British Retinis Pigmentosa Society

Sources:BBC NEWS:21st. April,’08

Categories
Ailmemts & Remedies

Congenital Blindness

Vision plays a very important part in the early development of a child. Impaired vision at birth will cause serious delay in development and is likely to lead to learning disabilities, particularly when associated with other problems, such as congenital deafness.

………………………………………………Jyotindra Mehta
Congenital blindness due to Retinitis Pigmentosa (RP) took away Jyotindra Mehta’s power of sight at a very young age. Emigration to the US on scholarship, coupled with a readiness to take up any challenge, resulted in Jyotindra’s quick success there.

and Nevy George
Congenital blindness due to Retinitis Pigmentosa (RP) took away thir eye sight at very early age.

About 9 in 10 children who are considered blind from birth have some vision, even though it may be only recognition of light and dark or shapes…..CLICK & SEE

Causes:
There are several causes including microphthalmos, cataracts, bilateral pseudogliomatous retinal detachments, and phthisis bulbi. OPPG is usually not suspected until fractures occur, frequently after seemingly minor trauma.

In the developed world, half of all cases of congenital blindness run in families and therefore may be due to a genetic disorder. another important cause is congenital infection such as the protozoal infection toxoplasmosis and the viral infection rubella. These infections are transmitted from the mother to the developing fetus during pregnancy and may lead to impaired vision in the newborn baby. congenital rubella is now rare in the developed world due to routine immunization. The baby’s eyes may also be affected by cataracts, in which the lenses are opaque, or glaucoma, in which the optic nerve is damaged due to increased pressure in the eyes. Congenital blindness may also be caused by damage to the brain as a result of lack of oxygen during birth.

Symptoms:
Parents usually become aware that their have a vision problem within a few weeks. he or she may less responsive than other babies, lying quietly to make the most of his or her hearing. parents may also notice that their baby:

· Is unable to fix his or her eyes on a close object.
· Has random eye movements.
· Does not smile by the age of 6 weeks.
· Has abnormally large, cloudy eyes if glaucoma is present.

Parents may find it difficult to bond with a quiet baby who does not smile.

Diagnosis:
If congenital blindness is not suspected by a baby’s parents, it will probably be picked up during a routine examination in infancy. A child suspected of having an impaired vision will be referred to a specialist for an examination and tests. His or her hearing will also be tested because, if the child is severely visually impaired, he or she will rely more on hearing.

Treatment:
It is possible to improve vision in only a smaller number of babies, such as those with cataracts or glaucoma. Early treatment of these conditions is important. cataracts are usually removed surgically within the first month of life. glaucoma may also be treated surgically to allow fluid to drain from the eye.

If vision cannot be improve, much can be done to help a child make maximum use of other senses or what little vision he or she has. if your child is diagnosed as blind, a team of specialist, including a teacher for the blind, will be able to give you and your child support and care. You will also be given advice on how to stimulate your child, by using your speech, sounds, and touch and how to adapt your home so that your child can explore it safely and develop self-confidence. Some children will require special schooling to learn braille, a system of raised dots that allows blind people to read.

Genetics counseling is available for parents of an affected child who wish to have more children or for prospective parents who are blind.

Click to see :
->

Preventable Causes of Congenital Abnormalities
Enzyme Responsible For Congenital Blindness
Prognosis :
Children treated for cataracts or glaucoma will probably still have impaired vision but often have enough sight to perform most activities unaided. Many blind or visually impaired children with no other disabilities go on to have successful personal and professional lives.

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose

Resources:
http://www.charak.com/DiseasePage.asp?thx=1&id=338
http://www.blonnet.com/ew/2005/03/07/stories/2005030700230200.htm

Categories
Ailmemts & Remedies

Nyctalopia(Night Blindness)

[amazon_link asins=’B073QK6B7B,B07439MJKR,B074DJS44T,B073QJVS1S,B073QJVGQQ,B073QJQ6JB,B0742XV6NR,B015KAOYHO,B074CQ3XJM’ template=’ProductCarousel’ store=’finmeacur-20′ marketplace=’US’ link_id=’a21d7a3a-78d4-11e7-8179-9f6a3bdf93c7′]

Night blindness (nyctalopia) is the inability to see well at night or in poor light. It is not a disorder in itself, but rather a symptom of an underlying disorder or problem, especially untreated nearsightedness.

Nyctalopia (Greek for “night blindness”) is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition (for example, a lack of vitamin A).

Causes:

Night blindness is due to a disorder of the cells in the retina that are responsible for vision in dim light. It has many causes, including:

The most common cause of nyctalopia is retinitis pigmentosa, a disorder in which the rod cells in the retina gradually lose their ability to respond to the light. Patients suffering from this genetic condition have progressive nyctalopia and eventually their daytime vision may also be affected. In X-linked congenital stationary night blindness, from birth the rods either do not work at all, or work very little, but the condition doesn’t get worse.Another cause of night blindness is a deficiency of retinol, or vitamin A, found in fish oils, liver and dairy products. In the Second World War misinformation was spread by the British to cover up the reason for their pilots’ successful night time missions. Their success was, in the misinformation, attributed to improved night vision and pilots flying night missions were encouraged to eat plenty of carrots, which contain carotenoids and can be converted into retinol. The actual reason for their success was their use of advanced radar technologies.

The opposite problem, known as hemeralopia, is much rarer.

The outer area of the retina is made up of more rods than cones. The rod cells are the cells that enable us to see in poor illumination. This is the reason why loss of side vision often results in night blindness. Individuals suffering from night blindness not only see poorly at night, but also require some time for their eyes to adjust from brightly lit areas to dim ones. Contrast vision may also be greatly reduced.

In order to determine what is causing night blindness, the eye doctor will perform a thorough eye exam and may order any of a number of specialized exams .

Historical usage
Aulus Cornelius Celsus, writing ca. 30 AD, described night blindness and recommended an effective dietary supplement: “There is besides a weakness of the eyes, owing to which people see well enough indeed in the daytime but not at all at night; in women whose menstruation is regular this does not happen. But success sufferers should anoint their eyeballs with the stuff dripping from a liver whilst roasting, preferably of a he-goat, or failing that of a she-goat; and as well they should eat some of the liver itself.”

Historically, nyctalopia, also known as moonblink, was a temporary night blindness believed to be caused by sleeping in moonlight in the tropics.
Treatment:

Treatment for night blindness will depend upon its cause. Treatment may be as simple as a new prescription for your eyeglasses or switching glaucoma medications, or it may require surgery in cases of cataracts.

Click for Alternative medication & life style to prevent night blindness

Vitamin A Deficiency, Prevention and Treatment through Ayurveda

CLICK TO SEE :Bilberry Extract Improve Night Blindness

Useful Herbs for Eye Care

Vitamine & mineral guide for eye care against Night Blindness

Night Blindness- Prevention,Treatment & Healing
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose

Resources:
http://en.wikipedia.org/wiki/Night_blindness
http://www.medicinenet.com/script/main/art.asp?articlekey=43325

Enhanced by Zemanta