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The blind can see now! Stem cells, gene therapy and devices that can beam images directly into the brain offer new hope to those without sight.
New hope about ending blindness!

Scientists have long known that while our eyes handle most of the heavy lifting of sight–taking in particles of light, bending and refracting them, converting them into electrical impulses–we actually "see" with our brains. Within its protective casing, each eye has a layer of receptors, a lens system that focuses light on these receptors, and a system of nerves that conducts impulses from the receptors to the brain. The way these components operate to set up conscious visual images is incredible!

Between the eye and the brain, however, a lot can go wrong, and until recently, if someone's vision started to go or was never there to begin with, there wasn't much doctors could do about it. Now, thanks to an explosion of new research, scientists at a stage in biology where they "know a heck of a lot about the causes of vision problems," says Dr. Paul A. Sieving, director of the National Eye Institute at the National Institutes of the Health. "When you know the cause of something, you can begin to think about how to ameliorate it." – [Source – TIME Health]. Globally, chronic eye diseases are the main cause of vision loss. Uncorrected refractive errors and un–operated cataracts are the top two causes of vision impairment. Over 80% of all vision impairment can be prevented or cured, now–a–days. Thanks to medical advances and expanding treatment, it’s no longer just a dream! Let's read on to know more facts about ending blindness!

Refractive errors are corrected with eyeglasses, contact lenses, or surgery.
Refractive errors:

Refractive errors occur when the shape of the eye prevents light from focusing directly on the retina. The length of the eyeball (longer or shorter), changes in the shape of the cornea, or aging of the lens can cause refractive errors. Myopia (nearsightedness) is a condition where objects up close appear clearly, while objects far away appear blurry. With myopia, light comes to focus in front of the retina instead of on the retina. Hyperopia (farsightedness) is a common type of refractive error where distant objects may be seen more clearly than objects that are near. Astigmatism is a condition in which the eye does not focus light evenly onto the retina, the light–sensitive tissue at the back of the eye. This can cause images to appear blurry and stretched out. Presbyopia is an age–related condition in which the ability to focus up close becomes more difficult. As the eye ages, the lens can no longer change shape enough to allow the eye to focus close objects clearly. All these refractive errors can be treated with providing correct glasses after the right identification of the problem.

Intraocular lens provide cataract patients with an extended depth of focus, and clear vision.
Glaucoma – Treatment aims a reduction of the intraocular pressure.
Visual impairments

Visual impairment is a decreased ability to see to a degree that causes problems not fixable by usual means, such as glasses. Visual impairment may cause people difficulties with normal daily activities such as driving, reading, socializing, and walking.  The most common causes of visual impairment globally if left untreated leads to blindness are:

Cataract: It is the world’s leading cause of blindness. A cataract is a clouding of the lens in the eye that affects vision. Cataracts are caused when proteins in the lens of an eye clump together, blocking and distorting light to the retina. Clumps of protein reduce the sharpness of the image reaching the retina. Most cataracts are related to aging. A cataract can occur in either or both eyes. It cannot spread from one eye to the other. Cataract surgery involves removing the clouded lens and replacing it with a clear artificial lens. The artificial lens, called an intraocular lens, is positioned in the same place as the natural lens. It remains a permanent part of the eye. Thus, surgery can restore sight.

Glaucoma: Glaucoma is caused by fluid buildup in the eye, resulting in pressure that can damage the optic nerve. The optic nerve is the important part of the eye which takes visual information gathered from our eye and transmits it using a series of electrical impulses to the parts of our brain that act as vision centers, allowing us to make sense of what we are seeing. The glaucoma often has no symptoms other than slow vision loss. Multitude surgeries are now available to treat Glaucoma. They are; Trabeculectomy involves an incision to remove a piece of tissue to allow fluid to drain from the eye. Tube–shunt surgery involves an incision to place a tube in the eye to allow fluid to drain. Laser trabeculoplasty burns tissue to create an opening that allows fluid to drain from the eye. If it's caught early enough, surgery and medication may slow its advance.

When macula damages, the center of vision becomes dark or blurry.
Age-related macular degeneration :

Age-related macular degeneration (AMD) is a common eye condition and a leading cause of vision loss among people age 50 and older. It causes damage to the macula, a small spot near the center of the retina and the part of the eye needed for sharp, central vision, which lets us see objects that are straight ahead. The macula is made up of millions of light-sensing cells that provide sharp, central vision. It is the most sensitive part of the retina, which is located at the back of the eye. The retina turns light into electrical signals and then sends these electrical signals through the optic nerve to the brain, where they are translated into the images we see. When the macula is damaged, the center of our field of view may appear blurry, distorted, or dark.

In some people, AMD advances so slowly that vision loss does not occur for a long time. In others, the disease progresses faster and may lead to a loss of vision in one or both eyes. Laser surgery will not restore vision that has already been lost because of macular degeneration. But it can sometimes slow down or delay further damage to a person's central vision.  It involves aiming an intense "hot" laser at the abnormal blood vessels in the eyes to destroy them. The growth of fragile new blood vessels in AMD recurs in about half of people within 3 years after surgery.

Vitrectomy–Vitreous humor gel that fills the eye cavity is removed to provide better access to the retina.
Diabetic Retinopathy

Diabetic Retinopathy is a complication of diabetes in which retinal(eye) blood vessels leak into the retina, causing macular edema (swelling). It is often caused by elevated blood sugar levels. Diabetic retinopathy causes over 8,000 cases of new blindness annually and is the primary cause of blindness for adults. Anyone with type 1 or type 2 diabetes can develop diabetic retinopathy, although those with uncontrolled blood sugar levels are at higher risk. Symptoms of diabetic retinopathy often begin with blurring of the vision that generally worsens over time. As it develops, people can experience cloudy vision, loss of color vision, shadows or blind spots, or floaters. People with diabetic retinopathy often have trouble seeing at night. Careful control of diabetes and regular eye exams can delay the development of the disorder. Diabetic retinopathy often develops without pain and with minimal symptoms at first. Because it can be treated after an early diagnosis, it is critical to have an annual eye exam and to report any change in vision. Vitrectomy (surgical treatment for diabetic retinopathy is removal of the vitreous gel) does not cure the disease, but it may improve vision in people who have developed bleeding into the vitreous gel (vitreous hemorrhage), retinal detachment, or severe scar tissue formation.

Stem cells reversing blindness!
Major advances to treat blindness!

As science nears closer to bringing incredible treatments for blindness to market, physicians will have to determine which option is best for which patient according to their severity and the competition will be fierce. For now, people are receiving cutting-edge experimental treatments that even a decade ago would have been unthinkable.

Stem cell therapy: Stem-cell treatments replenish the supply of retinal pigment epithelial (RPE) cells that bring nutrients to the retina. Because stem cells can develop into any cell type in the human body, they can be coaxed to become RPE cells–improving vision in people with genetic or age-related macular degeneration. Scientists take stem cells from excess IVF embryos and treat them with compounds that encourage them to grow, in a lab dish, into RPE cells. Up to 150,000 of these cells are then injected into the eye, where they grow. "Stem cells work like reseeding a lawn," says Dr. Carl Regillo, director of the retina service at Philadelphia's Wills Eye Hospital, who is conducting one of the trials using stem cells to treat blindness. "If you have a big patch of dead grass, you can spread grass seed and hope for uniform growth and replenish what is lost."[Source: TIME Health]

Bionic eye gives hope to the blind!
The Bionic eyes

People are suffering from blindness worldwide and millions of them are affected by low vision. It's no surprise that researchers are intent on developing novel ways to restore sight. One such effort is the development of a so-called bionic eye or bionic eye implants. The bionic vision system consists of a camera, attached to a pair of glasses, which transmits high-frequency radio signals to a microchip implanted in the eye. Electrodes on the implanted chip convert these signals into electrical impulses to stimulate cells in the retina that connect to the optic nerve. These impulses are then passed down along the optic nerve to the vision processing centers of the brain, where they are interpreted as an image. As such, the two medical conditions that this technology aims to address are retinitis pigmentosa and age-related macular degeneration.

Different bionic eye models take aim at different target areas in the visual pathway. Currently, retinal implants are the only approved and commercially available bionic eyes, though cornea transplants and cataract surgery can replace the cornea and lens if these structures are clouded or are incapable of focusing light for other reasons. And the first generation of bionic retinas–microchips that replace failed retinal cells by collecting or amplifying light–is bringing a low-resolution version of sight to people who for years saw nothing.

Thus, these advances encourage talk of something unthinkable just 10 or 20 years ago. Curing untreatable blindness once only a dream but now it is in reach with new therapies. Thus, ending the human blindness, soon.

References

  • http://time.com/4026658/blindness-cure-treatment/
  • https://www.nationalgeographic.com/magazine/2016/09/blindness-treatment-medical-science-cures/
  • https://www.mayoclinic.org/diseases-conditions/cataracts/diagnosis-treatment/drc-20353795
  • https://www.aao.org/eye-health/diseases/what-is-glaucoma