Argus II Retinal Implant

What is the Argus II retinal implant?

The Argus II retinal implant is an electronic instrument used to restore limited vision in patients who are blind in both eyes from retinitis pigmentosa. The retina is a thin layer of delicate tissue in the back of your eye, which lines the inside wall like the film in a camera. The retina “takes the picture” of objects and sends the message to the brain. Retinitis pigmentosa is a group of inherited diseases that affects the retina and may cause a profound loss of vision.

How does the Argus II retinal implant work?

The Argus II retinal implant system has several parts. There is a small video camera placed on glasses. The camera records video images and transmits the information to a video processor worn on the belt around the waist. The processor then converts the video information into a digital code that is transmitted to an implant that has been surgically inserted into the eye. The implant includes a set of diodes that are placed inside the eye on the surface of the retina and a coil that is secured to outside of the eye wall underneath the skin where it cannot be seen.

Who is eligible for the Argus II retinal implant?

In February 2013 The FDA granted approval for the use of the Argus II retinal implant only to patients with severe vision loss due to advanced retinitis pigmentosa. Eligible patients must have had good vision early in life and lost all but bare light perception or worse. Patients must also be older than 25 years of age. Researchers hope that with further research the device will be approved in the future for patients with less severe vision loss and for patients with other types of retinal disease. The implant is expected to become available in late 2013.

How much is the vision improved with the Argus II retinal implant?

The improvement in vision is very limited, but helpful in select patients. No clear image is seen. However, eligible patients with the retinal implant are able to see borders between light and dark. This allows them to function better with simple visual tasks such as walking and seeing objects with high contrast. The amount of improvement varies from patient to patient. Because there are risks to surgery, the FDA is appropriately cautious in its approval of the device only for patients with profound loss of vision.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3345188/

By Scott E. Pautler, MD

For a telemedicine consultation with Dr Pautler, please send email request to RvaAdmin@rvaf.com. We accept Medicare, most insurances, and self-pay.

Copyright  © 2001-2022 Designs Unlimited of Florida.  All Rights Reserved.

Myopia (near-sightedness)

globe anatomy
anatomy of the eye (click on image to enlarge)

What is myopia?

A myopic eye is a near-sighted eye.  Without glasses the vision is usually quite good at near, but blurred at distance.  Myopia affects 25% of Americans and about 22% of the world population. High myopia (greater than -6.00 diopters) is less common, affecting about 2% of the world population and projected to rise to 10% by the year 2050.

What causes myopia?

Myopia is an inherited condition that usually develops in childhood or early adulthood.  The eye, which is round like a ball at birth, becomes oval like an egg.  The outer appearance of the eye is not usually changed, but the elongation of the eye changes the focus of the eye from distance to near. There is evidence to suggest that extensive near work (e.g. reading) may worsen myopia.

myopia
A myopic eye has elongated somewhat like an egg. Incoming images do not focus on the retina in the back of the eye.

Why is it important to know about myopia?

Although most people with myopia do not develop complications, highly near-sighted people are at increased risk of losing vision from glaucoma, cataract, macular degeneration, and retinal detachment. The higher the degree of near-sightedness (myopia greater than -6.00 diopters), the greater the risk of loss of vision.

Glaucoma is a condition in which the pressure inside the eye damages nerve tissue that helps you see.  This pressure usually causes no pain or discomfort and pressure measurements may be normal at times.  Over months to years, the pressure slowly takes away the side vision.  If undetected and untreated, it may cause total blindness.  The best way to diagnose glaucoma is to have regular eye exams each year with pressure measurements.  Treatment is effective in preventing vision loss through the use of eye drops.  Sometimes, laser or surgery is needed.

Myopic macular degeneration is an uncommon cause of vision loss from severe myopia. The macula is the central part of the retina in the back of the eye.  The retina is a thin layer of delicate nerve tissue that lines the inside wall of the eye like the film in a camera.  In the eye, light is focused onto the retina, which “takes the picture” and sends the image to the brain.  In very near-sighted eyes, the retina becomes stretched as the eye elongates.  As a result, the central vision may become blurred or distorted even with proper glasses.  Distortion is when straight lines look wavy or crooked.  Blood vessels under the macula may bleed causing sudden blurring, blind spot, or distortion.  Any of these symptoms should be reported to the eye doctor without delay, as early treatment with medicine injections and/or laser may prevent further loss of vision.

Retinal detachment is a separation of the retina from the inside wall of the eye. When the retina detaches, it is no longer in proper position inside the eye.  Instead, it is like film that has unrolled inside a camera.  When this occurs, a camera cannot take a picture.  Similarly, when the retina detaches, the eye loses vision.  Warning symptoms prior to retinal detachment may include new floaters or brief flashes of light in the side-vision.  Later, a dark curtain or shadow slowly starts off to the side and takes away the vision as the retina detaches.  Laser or surgery repairs most retinal detachments.  It is important to diagnose a retinal detachment early in order to prevent permanent damage to the retina.  Report any new floaters, flashes, or loss of side-vision to your eye doctor without delay.

How is myopia treated?

The standard treatment of myopia is to refocus the eye with eye glasses or contact lenses. LASIK and PRK surgery flatten the cornea to focus images onto the retina. Orthokeratology is a controversial method used to flatten the cornea with contacts lenses worn overnight. Lens implants are a more aggressive measure to focus light in highly near-sighted eyes. All of these methods of treatment are simply aimed to focus the vision.  They are not designed to correct the underlying problem of elongation of the eye that leads to complications and loss of vision.  Diluted atropine eye drops appear to reduce the progression of myopia in an effort to avoid complications of severe elongation of the eye.

Will LASIK surgery help prevent these complications of myopia?

Although LASIK surgery is very effective at flattening the cornea to help eliminate the need for glasses, it does not restore the spherical shape to the eye.  Therefore, it is still necessary to be aware of the warning signs of possible complications from myopia.

What are the Do’s and Don’ts?

Using your eyes to read or work at a computer will not weaken them. Avoid intensive rubbing of your eyes.  Remember to have your eyes examined once a year.  Report the following symptoms to your eye doctor without delay:

¨     Blind spot or distortion of central vision

¨     New floaters or flashes of light

¨     Loss of side-vision

By Scott E. Pautler, MD

For a telemedicine consultation with Dr Pautler, please send email request to spautler@rvaf.com. We accept Medicare and most insurances in Florida. Please include contact information (including phone number) in the email. We are unable to provide consultation for those living outside the state of Florida.

Copyright  © 2001-2022 Designs Unlimited of Florida.  All Rights Reserved.