Two Patients With Macular Degeneration Get Artificial Retinas

LYON, France — A 72-year-old woman with dry age-related macular degeneration (AMD) was the first patient to receive an artificial retina implant as part of the multicenter PRIMAvera clinical trial, which is looking at the safety and efficacy of the PRIMA system.

“Her vision was severely impaired by this condition. We used the ETDRS chart to assess her visual acuity, as this is the current method in ophthalmology. She was able to read only nine letters,” said Laurent Kodjikian, MD, PhD, from Hôpital de la Croix-Rousse in Lyon, who is a former president of the French Society of Ophthalmology. To put that in perspective, a person with normal vision can make out 85 letters, he explained.

“The goal is to get her reading another ten letters,” he told Medscape Medical News.

The hospital where Kodjikian works is one of six centers in France selected to take part in the ongoing AMD clinical trial; other study sites are in Germany, Italy, the Netherlands, and Spain. The 38 study participants will be followed for 12 months after implantation to assess visual acuity and adverse events, and outcomes will be monitored for 3 years. Investigators hope that the findings will lead to the device receiving authorization to enter the market.

The PRIMA artificial retina system has three elements: a tiny wireless retinal implant; a pair of glasses with a camera and digital projector; and a portable processor connected to the projector. The camera captures visual scenes from the surrounding environment. The processor uses algorithms to process and simplify the images, which are then sent back to the glasses. The digital projector uses pulses of infrared light to project the processed images onto the retinal implant’s photovoltaic receptors. These receptors then convert the optical information into electrical stimulation, which excites the nerve cells of the inner retina, allowing them take in the information and transmit it, via the optic nerve, to the brain. This then induces visual perception.

A Delicate Operation

To implant the chip, Kodjikian made a rather large incision — 3.5 mm — and then peeled off the retina, all while looking through a surgical microscope.

“It’s easy to peel off the retina in a healthy eye. However, the procedure becomes more difficult in an eye affected by dry AMD, where the retina tissue is not only very thin and firmly attached to the back wall of the eye, but is also very fragile. A lot can go wrong during this step, so we have to really take our time,” he said. “You can’t go too deep, and if you go too close to the surface, you risk perforating the retina. Like walking on a very thin tightrope, there’s danger all around, and very little room for error.”

After the chip was inserted under the retina, Kodjikian put the retina tissue back into place. “This was the first time I’d ever done this kind of procedure, and it was quite a challenge,” he told Medscape.

The operation took 2.5 hours, which is much less time than the 4 to 5 hours estimated by the manufacturer.

The patient will undergo rehabilitation for 12 months to help her adapt to the system. “Our hope is that this patient will be able to see better with the implant. She probably won’t get to the point of being able to drive a car. And while reading novels in small print may not be possible, it’s quite likely that she’ll be able to read large-print editions,” Kodjikian explained.

Upon activation of the retinal prosthetic, the patient experienced visual impressions that she couldn’t see before the surgery. And 1 month after the procedure, things seem to be on track, according to a press release. “The postoperative result is excellent. There are no complications, the chip is perfectly in place and the vision has not been degraded by the operation. She should now start to improve thanks to rehabilitation,” said Kodjikian.

“Of the various artificial retina systems out there, this one is the most sophisticated because it has the most pixels. The technology will certainly continue to advance. But for the time being, the clinical study should allow us to show that it does work,” he concluded.

In December 2021, he implanted an artificial retina in a second patient, and it took him 50 minutes less than the first one.

This article originally appeared in the French edition of Medscape.

The authors have disclosed no relevant financial relationships.

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July 19, 2021

Prosthetic Contact Lenses

Prosthetic contact lenses are prescribed to mask flaws and improve the appearance of an eye disfigured from a birth defect, trauma, or eye disease.

If certain structures of the injured or disfigured eye also fail to function properly, special prosthetic lenses can be designed to block excess light from reaching the back of the eye to reduce glare and increase comfort.

Your eye care practitioner can match prosthetic contact lenses to the appearance of a healthy eye by using a pre-made trial set or by ordering custom-painted contact lenses.

Like regular contact lenses, prosthetic contacts can be made of gas permeable or soft lens materials. And most prosthetic lenses can be cleaned and disinfected using the same multipurpose contact lens solutions recommended for conventional soft or gas permeable lenses.

Custom prosthetic lenses can be made in a wide variety of lens powers to correct nearsightedness, farsightedness and/or astigmatism, or they can be produced without corrective power to simply provide a more natural appearance to a blind or disfigured eye.

Eye Conditions That May Benefit From Prosthetic Contact Lenses

Many injuries, conditions and infections can lead to disfigurement of an eye and make an individual feel self-conscious about his or her appearance. Prosthetic lenses can be specially designed to match the appearance of the unaffected eye as closely as possible and make the disfigured eye less conspicuous.

Disfiguring conditions frequently treated with prosthetic contact lenses include incomplete formation of the pupil (aniridia), lack of pigment or color in the eye (albinism) and damage to the cornea from trauma.

People with albinism or other eye conditions creating light sensitivity (photophobia) can benefit from prosthetic lenses that reduce the amount of light entering the eye. Prosthetic lenses also are sometimes used to eliminate double vision (diplopia) caused by certain eye conditions.

Special prosthetic colored contact lenses sometimes are used to improve vision in cases of childhood amblyopia. Two identical-appearing colored contacts are worn, but one lens has an opaque pupil painted on it to block (occlude) light from entering the eye. This lens is worn on the eye with normal sight, forcing greater use of the amblyopic eye to improve vision development in the affected eye.

Occlusion therapy with prosthetic contact lenses can be more effective for treating amblyopia than the use of an eye patch, which children often resist or remove due to embarrassment. But amblyopia treatment with contacts is more expensive due to the cost of the prosthetic lenses.

How Prosthetic Contact Lenses Are Prescribed

The first step in being fit with prosthetic contact lenses is to have a comprehensive eye exam. During this exam, your optometrist or ophthalmologist will thoroughly examine your eyes to rule out conditions that might interfere with successful prosthetic contact lens wear.

The second step is to undergo a contact lens fitting. In addition to performing the steps in a normal contact lens exam and fitting, your eye doctor may also take close-up photographs of your eyes. These color photos are sent to the prosthetic contact lens manufacturer to help the company create a prosthetic lens that matches your natural eye color and appearance as closely as possible.

Some eye doctors who specialize in contacts for hard-to-fit eyes also may have fitting sets of sample prosthetic lenses on hand so you can get an immediate idea of how effectively the lenses can restore a natural appearance to your affected eye(s).

June 28, 2021

Contact Lens Prescription Calculator

Click to convert your eyeglasses prescription to contact Lens prescription

May 27, 2021

After 40 years of blindness, injection of light-sensitive protein restores a man’s vision

The first successful clinical test of a technique called optogenetics has allowed a 58-year-old man to see for the first time in decades.

The man was able to see with the help of image-enhancing goggles after 40 years of blindness, thanks to an injection of light-sensitive proteins into his retina.

According to a study published by Nature Medicine on May 24, this is the first successful clinical application of optogenetics, a technique in which flashes of light are used to control gene expression and neuron firing.

The study revealed that the technique is widely used in laboratories to probe neural circuitry and is being investigated as a potential treatment for pain, blindness and brain disorders.

The clinical trial, run by the company GenSight Biologics, based in Paris, enrolls people with retinitis pigmentosa — a degenerative disease that kills off the eye’s photoreceptor cells, which are the first step in the visual pathway.

In a healthy retina, photoreceptors detect light and send electrical signals to retinal ganglion cells, which then transmit the signal to the brain.

GenSight’s optogenetic therapy skips the damaged photoreceptor cells entirely by using a virus to deliver light-sensitive bacterial proteins into the RGCs, allowing them to detect images directly.

GenSight is one of several companies developing optogenetics as a treatment for RP and other disorders of the retina.

In March, Nirenberg’s company Bionic Sight announced that four of the five people with RP it had treated with a similar optogenetic therapy and a virtual-reality headset had recovered some level of vision, although the full trial results have not yet been published.

Also, Swiss pharma giant Novartis is developing a therapy based on a different protein that is so light-sensitive that goggles might not be needed. That therapy has not yet entered clinical trials.

The researchers injected the virus into the eye of a man with RP, then waited four months for protein production by the RGCs to stabilise before testing his vision, the Nature Medicine reported.

José-Alain Sahel, an ophthalmologist at the University of Pittsburgh Medical Center in Pennsylvania and leader of the study, says that one of the challenges was regulating the amount and type of light entering the eye, because a healthy retina uses a variety of cells and light-sensitive proteins to see a wide range of light.

“No protein can replicate what the system can do,” he says. So the researchers engineered a set of goggles that captured the visual information around the man and optimised it for detection by the bacterial proteins.

Using a camera, the goggles analyse changes in contrast and brightness and convert them in real-time into what Sahel describes as a ‘starry sky’ of amber-coloured dots. When the light from these dots enters a person’s eye, it activates the proteins and causes the RGCs to send a signal to the brain, which then resolves these patterns into an image.

The trial participant had to train with the goggles for several months before his brain adjusted to interpret the dots correctly. “He was like an experimentalist, a scientist trying to understand what he was seeing and make sense of it,” Sahel says.

Eventually, he was able to make out high-contrast images, including objects on a table and the white stripes in a crosswalk. When the researchers recorded his brain activity, they found that his visual cortex reacted to the image in the same way as it would have if he had normal sight.

The man still can’t see without the goggles, but Sahel says that he wears them for several hours per day and that his vision has continued to improve in the two years since his injection.

Sahel says six other people were injected with the same light-sensitive proteins last year, but the COVID-19 pandemic delayed their training with the goggles.

A neurobiologist at the University of California, John Flannery says the study “is a big step for the field.

“The most important thing is that it seems to be safe and permanent, which is really encouraging.”

Flannery said while the image may never be as good as natural vision, it is exciting that the brain can interpret images accurately.

Other researchers are, however, calling for more studies.

Sheila Nirenberg, a neuroscientist at Weill Cornell Medical College in New York City says she looks forward to seeing whether the other people in the trial, including some who were injected with higher doses of the protein, have similar results.

“It’s interesting, but it’s an N of 1,” she says.

Karl Deisseroth, a neuroscientist at Stanford University in California who co-developed optogenetics as a lab technique, says the study is important because it is the first time that the technique’s effects have been shown in people.

“It will be interesting to try this with more light-sensitive opsins” that might not require goggles, he says. But he expects optogenetics to be most useful as a research tool that leads to therapies, rather than a therapy itself.

“What we hope to see even more of is optogenetics-guided human and clinical studies,” he says.

May 24, 2021

How to maintain health eyes

Good vision helps you perform well—at home, at work, or behind the wheel. That’s why it’s important to take a few simple steps to make sure you help keep your eyesight at its best. A regular eye exam is the best way to protect your eyesight – and an easy precaution to take. Here are some tips to help maintain eye health as you age.

Eat a Balanced Diet

fruit vegetables As part of your healthy diet, choose foods rich in antioxidants, like Vitamins A and C; foods like leafy, green vegetables and fish. Many foods – especially fatty fish, such as salmon – contain essential omega-3 fatty acids that are important to the health of the macula, the part of the eye responsible for central vision.

An inadequate intake of antioxidants, consumption of alcohol or saturated fats may create free-radical reactions that can harm the macula – the central part of the retina. High-fat diets can also cause deposits that constrict blood flow in the arteries. The eyes are especially sensitive to this, given the small size of the blood vessels that feed them.

Your eyes are unique, and have their own set of nutritional needs. Ocuvite eye vitamins are specially designed to provide a balanced combination of nutrients dedicated to the health of your eyes.* Visit Ocuvite.com to learn more.

Exercise

Exercise improves blood circulation, which improves oxygen levels to the eyes and the removal of toxins.

Get a good night’s sleep

You’ll feel the difference when you get the sleep you need. You’ll look great, you’ll perform at home or work—and good rest will support the health of your eyes.

Wash your hands

Keeping your hands clean is so important when it comes to your eyes, especially if you’re a contact lens wearer. Before you touch your eye—and before you put in or remove a contact lens—wash your hands with a mild soap and dry with a lint-free towel. Some germs and bacteria that come from your hands can cause eye infections, like bacterial conjunctivitis (pink eye). When you touch your eye, whatever is on your fingers goes right onto your eye’s surface. This is one way that people catch colds—rubbing their eyes while they have cold virus germs on their hands.

Don’t Smoke

Smoking exposes your eyes to high levels of oxidative stress. While the connection has not been clearly identified, it is known that smoking increases your risk for a variety of health conditions affecting the eye. To help you quit, visit the American Lung Association’s free online smoking cessation program – Freedom From Smoking Online – at www.ffsonline.org.

Wear Sunglasses

To protect your eyes from harmful ultraviolet (UV) light, choose sunglasses with both UVA and UVB protection. Also, wearing a hat with a brim will greatly reduce the amount of UV radiation slipping around the side of your sunglasses.

Devices and Blue Light

You’re probably using digital devices for hours each day at work and at home. These devices are exposing your eyes to high energy blue light. It’s called blue light because the wavelengths emitted are near the bluer part of the spectrum. Lutein & Zeaxanthin are eye nutrients that are concentrated in the macula and help eyes filter blue light.* Lutein and Zeaxanthin cannot be produced by our bodies on their own, so they must be obtained through diet and/or supplements. If you don’t think you’re getting enough in your diet, visit Ocuvite.com to learn more.

Here are some other tips to help when you’re on your computer:

Keep your computer screen within 20″-24″ of your eye.
Keep the top of your computer screen slightly below eye level.
Adjust lighting to minimize glare on the screen.
Blink frequently.
Take a break every 20 minutes to focus on an object 20 feet away for 20 seconds.
Use lubricating eye drops to soothe irritated, dry eyes.

February 3, 2021

Bandage Contact Lenses

The Case for Bandage Soft Contact Lenses

A primer on the use of these therapeutic lenses to serve and protect the corneas of our patients.

By Susan Gromacki, O.D., M.S., F.A.A.O.

The concept of a protective eye bandage originated in the first century A.D., when Celsus reportedly applied a honey-soaked linen to the site of a pterygium removal to prevent symblepharon development.^1,2 Bandage soft contact lenses were first used in the 1970s following the development of hydroxyethyl methacrylate (HEMA) by Otto Wichterle.² With the recent advances in material technology, today’s bandage contact lenses provide the same benefits as their predecessors—but with enhanced convenience, improved healing and increased corneal health.

Bandage Lens Basics
By definition, a bandage contact lens protects the cornea. Many different lens types can be utilized to accomplish this goal (see tables 1 and 2); however, because of their high oxygen permeability and FDA approval for extended wear, silicone hydrogel soft contact lenses are currently most practitioners’ first choice.

Bandage lenses protect the cornea not only from potential exterior sources of injury, but also from a patient’s own eyelids. The shearing effect created by the lids during the blink can inhibit re-epithelialization and cause pain. Use of a bandage lens facilitates corneal healing in a pain-free environment.

Depending on the patient’s ocular condition, he or she may wear their therapeutic lenses for a period of days to years. They may be utilized for daily or extended wear (see table 2). Because there is generally an underlying disease process precipitating the need for a therapeutic lens, extra caution must be taken to clean and disinfect the lens after wear, keeping in mind that silicone hydrogel lenses tend to deposit lipids more readily than HEMA lenses (see image 1). That said, the addition of a digital rubbing step is necessary for lenses that are used more than once.

It is critical to perform frequent follow-ups for bandage contact lens patients. One reason is that a bandage lens fit, by design, demonstrates less movement than a traditional soft lens fit. The theory is to provide increased patient comfort while preventing the healing epithelial cells from sloughing off due to any mechanical trauma of the lens itself.³ In addition, it is important for the practitioner to be vigilant regarding the detection of signs of microbial keratitis. The compromised cornea—especially when wearing lenses in an extended wear modality—is at particular risk for infection.⁴

Indications
Bandage contact lenses are indicated for many different reasons, including: protecting the eyes, increasing comfort, facilitating healing and sealing wound leaks. We’ll explore these indications, and others, in more detail in the following paragraphs.

• Protection. Corneal protection is needed in the case of several conditions, including: entropion, trichiasis, tarsal scars, recurrent corneal erosion, post-surgical ptosis and surgical sutures or exposed suture knots.

Recurrent erosions are a typical sequella of epithelial basement membrane (basal lamina) trauma or are secondary to anterior basement membrane dystrophy, anterior basement membrane degeneration or stromal dystrophy. A bandage contact lens is the second line of treatment, after hyperosmotic drops and/or ointment fail.^2,5 An added benefit is the enhanced vision provided by the smooth refracting surface of the contact lens, as opposed to an irregular anterior corneal surface.5 Hypertonic saline drops should continue to be utilized concurrently with the lenses.

• Pain relief. The mitigation of corneal pain is another important indication for therapeutic contact lenses. The conditions most in need of this therapy include bullous keratopathy; epithelial erosion and abrasion; filamentary keratitis; and postoperative penetrating keratoplasty.

In bullous keratopathy, endothelial failure results in corneal edema, which in turn creates epithelial blisters that rupture, causing pain, foreign body sensation, and photophobia. A bandage contact lens reinforces the damaged tissues and protects the nerve endings from the abrasive actions of the eyelids. Patients who are awaiting a conjunctival flap or cornea transplant may be fitted with therapeutic lenses for up to 30 days at a time.²
Until recently, pressure patching was the standard of care for treating large epithelial abrasions (see figure 2). With this treatment, the caveat was to refrain from patching contact lens wearers or injuries caused by presumed vegetative matter or false fingernails. The utilization of a bandage contact lens provides protection and healing for all three of these conditions, and it has now supplanted patching as the standard of care. The authors of the Wills Eye Manual caution, however, that prophylactic topical antibiotics should be used concurrently and that daily follow-up care is mandatory.⁶

The other advantage of bandage contact lenses over patching is the ability to continue to install topical ophthalmic medications. This is particularly important after a corneal abrasion, erosion, or corneal refractive surgery, which necessitate the frequent installation of antibiotics and/or artificial tears. Some reports caution against the installation of cycloplegic agents (which reduce the pain associated with a corneal abrasion/erosion or after corneal refractive surgery) in bandage CL wearers. The dilating drops can cause the bandage lenses to dry out and become less comfortable, especially overnight, with the end result a potentially decreased healing response.⁷ On the other hand, bandage contact lenses can be utilized—by design—as vehicles for drug delivery, but the exact way to ensure a consistent dosage is still under investigation.

• Healing. The use of bandage contact lenses to facilitate healing is particularly necessary for the following conditions: chronic epithelial defects, corneal ulcer, neurotrophic keratitis, neuroparalytic keratitis, chemical burns and basement membrane disease.

They also enhance healing following corneal surgery, particularly refractive surgery. They protect the cornea from exposure or from the irritation caused by rubbing the eye as the corneal wounds are healing. Therapeutic bandage contact lenses are a mainstay after photorefractive keratectomy (PRK) procedures, in which the removal of the epithelium leaves an open wound that takes about one week to heal (see figure 3). They are also valuable for the following procedures: laser-assisted in situ keratomileusis (LASIK), laser-assisted subepithelial keratomileusis (LASEK), Epi-LASIK, penetrating keratoplasty (PK) and phototherapeutic keratectomy (PTK), lamellar grafts and corneal flaps.

• Sealing. The lenses also may aid in sealing leaky wounds. Serving as a splint or sealant, the lenses can be beneficial after cataract, penetrating keratoplasty or glaucoma filtering surgery.

• Maintenance of corneal hydration. The role of bandage contact lenses in dry eye is controversial. For patients who need to continually instill lubricating drops into their eyes, particularly after refractive surgery, the benefits of using a bandage lens can be great. Other patients who benefit are those who have significant lagophthalmos and subsequent corneal exposure. However, contact lenses are generally contraindicated for dry eye.⁷

• Structural stability and protection in piggyback lens fitting. Many patients benefit from the utilization of a soft and rigid lens concurrently. The rigid lens provides crisp vision, particularly for irregular corneas, and the soft bandage lens protects the cornea, preventing irritation and abrasions. Examples include elevation differences in the host/graft junction, keratoconus and in the presence of scar tissue.

Contraindications

Each clinician must assess his patient’s condition carefully to determine whether a bandage contact lens is warranted. Interestingly, many of the conditions that require bandage contact lenses (dry eye, infection, inflammation, etc.) contraindicate lens wear in general. In addition, therapeutic contact lenses should not be used in patients who are unwilling or unable to comply with the necessary treatment and follow-up.

Dr. Gromacki is a diplomate in the Cornea, Contact Lens and Refractive Technologies Section of the American Academy of Optometry. She is Chief Research Optometrist at Keller Army Community Hospital, West Point, New York.

1. Arrington GE. A history of ophthalmology. MD Publishers, New York, New York, 1959.
2. Weiner BM. Therapeutic bandage lenses. In: Silbert JA, ed. Anterior Segment Complications of Contact Lens Wear. Churchill Livingstone, New York, New York, 1994; 455-471.
3. Aquavella JV. Chronic corneal edema. Am J Ophthalmol 1973;(76):201-207.
4. Thoft RA, Mobilia EF. Complications with therapeutic extended wear soft contact lenses. Int Ophthalmol Clin. 1981;(21):197.
5. Chan WE, Weissman BA. Therapeutic contact lenses. In: Bennett ES, Weismann BA, (eds). Clinical Contact Lens Practice, Lippincott Williams & Wilkins: New York, New York, 2005: 619-628.
6. Ehlers JP and Shah CP, eds. The Wills Eye Manual Fifth Edition, Wolters Kluwer Health, New York, New York, 2008:15-16.
7. Russell GE. Bandage lenses: new opportunities in practice. Contact Lens Spectrum. 2004(6).
8. Tyler Thompson TT. Tyler’s Quarterly 2011;28(3):32-52.
9. White P. 2011 Contact Lenses and Solutions Summary. In: Contact Lens Spectrum (suppl) 2011;27(7):14.

August 22, 2020

Glaucoma

Glaucoma is a condition that damages your eye‘s optic nerve. It gets worse over time. It’s often linked to a buildup of pressure inside your eye. Glaucoma tends to run in families. You usually don’t get it until later in life.

The increased pressure in your eye, called intraocular pressure, can damage your optic nerve, which sends images to your brain. If the damage worsens, glaucoma can cause permanent vision loss or even total blindness within a few years.

Most people with glaucoma have no early symptoms or pain. Visit your eye doctor regularly so they can diagnose and treat glaucoma before you have long-term vision loss.

If you lose vision, it can’t be brought back. But lowering eye pressure can help you keep the sight you have. Most people with glaucoma who follow their treatment plan and have regular eye exams are able to keep their vision.

Glaucoma Causes

The fluid inside your eye, called aqueous humor, usually flows out of your eye through a mesh-like channel. If this channel gets blocked, the liquid builds up. Sometimes, experts don’t know what causes this blockage. But it can be inherited, meaning it’s passed from parents to children.

Less-common causes of glaucoma include a blunt or chemical injury to your eye, severe eye infection, blocked blood vessels inside your eye, and inflammatory conditions. It’s rare, but eye surgery to correct another condition can sometimes bring it on. It usually affects both eyes, but it may be worse in one than the other.

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Glaucoma Risk Factors

It mostly affects adults over 40, but young adults, children, and even infants can have it. African Americans tend to get it more often, when they’re younger, and with more vision loss.

You’re more likely to get it if you:

Are of African American, Irish, Russian, Japanese, Hispanic, Inuit, or Scandinavian descent
Are over 40
Have a family history of glaucoma
Have poor vision
Have diabetes
Take certain steroid medications such as prednisone
Have had an injury to your eye or eyes
Have corneas that are thinner than usual
Have high blood pressure, heart disease, diabetes, or sickle cell anemia
Have high eye pressure
Are nearsighted or farsighted

Types of Glaucoma

There are two main kinds:

Open-angle glaucoma. This is the most common type. Your doctor may also call it wide-angle glaucoma. The drain structure in your eye (called the trabecular meshwork) looks fine, but fluid doesn’t flow out like it should.

Angle-closure glaucoma. This is more common in Asia. You may also hear it called acute or chronic angle-closure or narrow-angle glaucoma. Your eye doesn’t drain like it should because the drain space between your iris and cornea becomes too narrow. This can cause a sudden buildup of pressure in your eye. It’s also linked to farsightedness and cataracts, a clouding of the lens inside your eye.

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Less common types of glaucoma include:

Secondary glaucoma. This is when another condition, like cataracts or diabetes, causes added pressure in your eye.

Normal-tension glaucoma. This is when you have blind spots in your vision or your optic nerve is damaged even though your eye pressure is within the average range. Some experts say it’s a form of open-angle glaucoma.

Pigmentary glaucoma. With this form, tiny bits of pigment from your iris, the colored part of your eye, get into the fluid inside your eye and clog the drainage canals.

Glaucoma Symptoms

Most people with open-angle glaucoma don’t have symptoms. If symptoms do develop, it’s usually late in the disease. That’s why glaucoma is often called the “sneak thief of vision.” The main sign is usually a loss of side, or peripheral, vision.

Symptoms of angle-closure glaucoma usually come on faster and are more obvious. Damage can happen quickly. If you have any of these symptoms, get medical care right away:

Seeing halos around lights
Vision loss
Redness in your eye
Eye that looks hazy (particularly in infants)
Upset stomach or vomiting
Eye pain

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Glaucoma Diagnosis

Glaucoma tests are painless and don’t take long. Your eye doctor will test your vision. They’ll use drops to widen (dilate) your pupils and examine your eyes.

They’ll check your optic nerve for signs of glaucoma. They may take photographs so they can spot changes at your next visit. They’ll do a test called tonometry to check your eye pressure. They may also do a visual field test to see if you’ve lost peripheral vision.

Glaucoma Treatment

Your doctor may use prescription eye drops, oral medications, laser surgery, or microsurgery to lower pressure in your eye.

Eye drops. These either lower the creation of fluid in your eye or increase its flow out, lowering eye pressure. Side effects include allergies, redness, stinging, blurred vision, and irritated eyes. Some glaucoma drugs may affect your heart and lungs. Be sure to tell your doctor about any other medications you’re taking or are allergic to.

Oral medication. Your doctor might also prescribe medication for you to take by mouth, such as a beta-blocker or a carbonic anhydrase inhibitor. These drugs can improve drainage or slow the creation of fluid in your eye.

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Laser surgery. This procedure can slightly raise the flow of fluid from your eye if you have open-angle glaucoma. It can stop fluid blockage if you have angle-closure glaucoma. Procedures include:

Trabeculoplasty. This opens the drainage area.
Iridotomy. This makes a tiny hole in your iris to let fluid flow more freely.
Cyclophotocoagulation. This treats areas of the middle layer of your eye to lower fluid production.

Microsurgery. In a procedure called a trabeculectomy, your doctor creates a new channel to drain the fluid and ease eye pressure. This form of surgery may need to be done more than once. Your doctor might implant a tube to help drain fluid. This surgery can cause temporary or permanent vision loss, as well as bleeding or infection.

Open-angle glaucoma is most often treated with combinations of eye drops, laser trabeculoplasty, and microsurgery. Doctors tend to start with medications, but early laser surgery or microsurgery could work better for some people.

Infant or congenital glaucoma — meaning you are born with it — is usually treated with surgery because the cause is a problem with your drainage system.

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Glaucoma Prevention

You can’t prevent glaucoma. But if you find it early, you can lower your risk of eye damage. These steps may help protect your vision:

Have regular eye exams. The sooner your doctor spots the signs of glaucoma, the sooner you can start treatment. If you’re over age 40 and have a family history of the disease, get a complete eye exam from an eye doctor every 1 to 2 years. If you have health problems like diabetes or are at risk of other eye diseases, you may need to go more often.
Learn your family history. Ask your relatives whether any of them have been diagnosed with glaucoma.
Follow your doctor’s instructions. If they find that you have high eye pressure, they might give you eye drops to prevent glaucoma.
Exercise. Moderate activity like walking or jogging at least three times a week might help lower eye pressure.
Protect your eyes. Use protective eyewear when playing sports or working on home improvement projects

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July 29, 2020

Buy freshlook contact lenses at N2000/pair with 120ml solution, storage case and picker within in Ajuwon Giwa Okearo Alagbole Akute

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July 25, 2020

Corneal layers and corneal transplant -Eye care perspective

What are the different layers of the cornea?

The cornea is the clear front wall of the eye, similar to a watch crystal. Functionally, the cornea has 3 main layers. All layers are clear and must be so to focus light properly.

The outer 10% of the cornea, the epithelium, is the protective skin layer that has sensation. It tells you to blink when your eyes are dry or if you get something in it. The epithelium protects the stroma from infection, scarring, drying out, and other potential harm. Just like the outer layer of your skin, the corneal epithelium sheds and regenerates itself every week. The new cells are grown by corneal epithelial stem cells. Therefore, an eye with an area of bad or opaque epithelium that blocks vision likely does not need a transplant to remove to opacity. Instead of the opacity typically only needs to be removed so that new healthy and clear epithelium can grow in (superficial keratectomy or SK). All other corneal layers do not regenerate and would need to be replaced or transplanted if removed.

The middle layer, the stroma, is the tough structural portion that makes up about 85% of the cornea thickness. The stroma is covered on the outside by the epithelium and on the inside by Descemet’s membrane.

The inner layer of the cornea, Descemet’s membrane, makes up 3 to 5% of its thickness. It is a thin Saran wrap-like membrane that has a single layer of extremely important endothelial cells living on its inner surface. The cornea needs oxygen and nutrients delivered to it, but it does not have blood flow like other parts of the body since blood vessels would make it opaque. The cornea is nourished by a clear fluid called aqueous humor. Aqueous inside the eye is made by arteries and is drained by veins. Descemet’s membrane limits the rate that aqueous humor can flow into the cornea. The endothelial cells pump out “used” aqueous humor so that it does not build up in the cornea which would otherwise make it opaque.

Corneal Layer Diagram

Is it possible to remove and/or transplant just one layer of the cornea?

Yes. We can explain the different types of cornea transplantation using the analogy of a wall. Think of the stroma as the drywall and bricks, Descemet’s membrane and endothelium as the wallpaper, and the epithelium as the temporary protective layers of clear coat that the owner must paint on the bricks from time to time.

Not that long ago, the only available surgery was a full thickness cornea transplant or penetrating keratoplasty (PK). With PK, all of the corneal layers are transplanted, and new epithelial cells grow over the new cornea in time. The entire wall is knocked out with a hammer, and a new wall and all its layers are brought in. The owner provides a new layer of clear coat over time. A prosthetic corneal transplant (keratoprosthesis (KPro) is an artificial full-thickness corneal transplant.

Selective keratoplasty surgeries are a huge advance over PK in that they allow us to replace just the portion of the cornea that is diseased.

Selective Keratoplasty Diagram

- Superficial keratectomy (SK) and phototherapeutic keratectomy (PTK) remove the epithelium (and possibly some superficial stroma with PTK) so that new healthier epithelium can grow in. The corneal epithelium is the only layer of the cornea that regenerates. So, SK and PTK aren’t true transplants. They are like removing some imperfections in the layer of clear coat on the outside of the house so that the owner can lay down new clear coat. Conversely, an epithelial stem cell transplant is necessary when the owner’s can of clear coat runs out or goes bad. It becomes necessary to give the owner a new supply of clear coat, which involves transplanting in a special area of a donor cornea.

- Deep anterior lamellar keratoplasty (DALK) transplants all stroma but leaves the host’s healthy Descemet’s membrane and endothelium behind to allow less risk of rejection or less risk from blunt trauma. The entire wall is changed out, but the host’s own delicate wallpaper is left behind.

Descemet’s membrane endothelial keratoplasty (DMEK) and Descemet’s stripping automated endothelial keratoplasty (DSAEK) replace Descemet’s membrane and endothelium without removing the host’s stroma. DMEK is more selective than DSAEK. Both DMEK and DSAEK remove old Descemet’s membrane and endothelium. DMEK adds a new Descemet’s membrane and endothelium only. DSAEK also adds a new Descemet’s membrane and endothelium but with an additional layer of donor stroma. Using the wallpaper analogy, in both DMEK and DSAEK the old wallpaper is removed. With DMEK, only new wallpaper is inserted. With DSAEK, a new piece of drywall that has new wallpaper on it is inserted on top of the old drywall.

Why do we need different types of transplants? Why not just do PK for everyone

PK has many limitations regarding vision, astigmatism, recovery time, rejection rate, and other risks. All types of selective transplants improve the outcomes when compared to PK. DMEK especially has many other benefits compared to DSAEK and PK. For example, performing PK for purely endothelial disease is outdated. It would be like knocking down the wall and bringing in a whole new wall when the only thing needed is new wallpaper!

Cornea Transplant Procedures Diagram

Do I need to go on systemic immunosuppressive medications for a corneal transplant?

Not for most types of corneal transplants. Epithelial stem cell transplants are an exception. When someone gets a kidney or a heart transplant, they need to go on strong medications that make the immune system less aggressive and less likely to attack the transplant. These medications have some potentially significant side effects.

Because there are no blood vessels in the cornea, it is generally invisible to the immune system. Thus for corneal transplants, with the exception of epithelial stem cell transplants, we only need anti-inflammatory eye drops to prevent an immune system attack or rejection. Most patients get down to one drop a day after several few months.

Rarely, patients with aggressive immune systems require stronger systemic medications to prevent rejection. Even with aggressive immune systems, rejection is still very rare with DMEK and is more commonly seen with DSAEK, DALK, or PK. PK has the highest risk of rejection.

After a corneal transplant, do I have to take any precautions if I ever receive a vaccination?

There is some data to suggest that the increase in the immune system activity after vaccination, including the flu and shingles vaccines, may put the graft at a slightly increased risk for a rejection episode. To combat this, we typically recommend that if you were down to just one steroid drop a day, immediately following a vaccine you should increase the steroid drops to four times a day for one week, then two times a day for one week, and then go back to just one daily. If you have previously been told that you cannot take steroid drops due to pressure problems or other issues, ask your cornea surgeon for advice before getting a vaccine. transplant.

How long will my transplant last?

Traditional full thickness corneal transplants (PK) last about 20 years. Cell count studies show that, with the passage of time, transplants still lose endothelial cells gradually just like any other cornea, but usually at a faster rate. When the endothelial cell counts fall low enough, the transplant becomes opaque and fails. Since DMEK and DSAEK are relatively new, it is not possible to say how long they will last; however, preliminary data is encouraging, especially for DMEK. There is variation between transplants, but early data suggest some transplants can even last one’s lifetime. Either way, the replacement of a transplant is possible.

Dr. Tenkman is studying variables that may reveal which donors have cells that are more resistant to death and also surgical techniques that are minimally harmful to endothelial cells. Many surgeons suggest it is normal to lose 30 to 50% of the donor’s endothelial cells during surgery. We have some early data suggesting less than 10% cell loss from surgery when selecting a specific subset of donors.

Does a rejection episode mean that I will lose my cornea transplant?

No. If untreated, a rejection episode can cause significant damage. But usually, the episode stops with an increase in anti-inflammatory eye drops. Patients are instructed to RSVP: come see us if they develop Redness, Sensitivity to light, Vision reduction, or Pain. It’s key to see us right away for prompt diagnosis and treatment.

Will I need glasses after my transplant? Could laser vision correction be done to reduce any postoperative need for glasses?

Whether or not you need glasses after your transplant depends on many factors. DMEK transplants reduce glasses dependence the most often. DSAEK is less predictable. DALK and PK can both frequently cause high astigmatism that needs glasses or even hard contacts to attain good vision.

Some patients are candidates for ASA (advanced surface ablation) to minimize their dependence on glasses or contacts after corneal transplant surgery. ASA is a laser vision correction procedure similar to LASIK. Whether or not ASA could be done to reduce dependence on glasses or contacts after surgery depends on several factors and is taken on a case by case basis.

What are the costs and risks of a cornea transplant?

Corneal transplant tissue is donated, but still typically costs $3,700 or more. The fees go to the eye banks that must harvest the corneas, screen for possible diseases that could be transferred to the patient, transport, and process the corneas, and deliver them to the surgery center… all within just a few days. The cost of receiving a transplant includes not just the tissue, but the surgery center, surgeon, and anesthesia fees. Fortunately, these costs are less at an outpatient surgery center and are typically covered by Medicare and private insurance, although patients may be responsible for deductibles and co-payments. Generally, DMEK and DSAEK can be performed in an outpatient surgery center whereas DALK and PK more often have to be done at a hospital. Having surgery at a hospital can increase costs several-fold.

The risk of infection from a corneal transplantation procedure is about the same as following a routine blood transfusion. The risk of receiving a disease from a transplant is very low.

Other risks include primary graft failure, rejection, graft dislocation, cataract formation, glaucoma, infection, irregular astigmatism, double vision, bleeding, iris damage, vitreous prolapse, and cystoid macular edema. Most of these complications are quite rare but are theoretically possible with all types of eye surgery. Patients using steroid drops, which all corneal transplants require, have to be followed for the development of increased pressure. High eye pressure usually gives no symptoms, so follow up is crucial to allow the doctor to treat as necessary with medication or procedures. Patients are usually seen every 3 to 6 months for life depending on the strength of steroid used.

In our hands, the overall success rate for a DMEK or DSAEK graft attaching and working well is about 99%. Should the transplant fail due to rejection or otherwise, it would need to be repeated.

Because the time to heal is longer for DALK and PK, and because they involve more risk, the odds of a DALK or PK failing to restore vision is more significant than for DMEK or DSAEK. DALK and PK have several additional risks.

DALK, and more so PK, have a higher risk of bleeding during surgery while the patient’s own cornea is removed and the eye is depressurized. Although not common, such bleeding can do significant damage to the eye.
DALK, and more so PK, also have a significant risk of rejection. Higher doses of steroid drops may be necessary in here to prevent or treat rejection, which can increase the risk of increased eye pressure (glaucoma).
DALK and PK involve a 360-degree corneal incision. Such large corneal wounds don’t heal with full strength and are at risk to split open with moderate blunt trauma (ie if a patient fell and hit their face in the shower). If the wound were to split open, it could lead to loss of the eye.
DALK and PK require about 16 sutures. These sutures are not removed for many months or even over a year. The sutures are buried in a manner so they cause no pain to the patient. However, they commonly become loose and can cause a foreign body or sandy sensation. More significantly, a loose suture is a risk for infection (corneal ulcer). Corneal ulcers can be more serious in the setting of a corneal transplant because the immune system in the area is suppressed by steroid eye drops.
DALK and PK commonly heal with large amounts of astigmatism. The normally spherical corneal surface becomes like an irregularly shaped egg. Since the smooth corneal shape largely determines focus, an irregular cornea causes blurred vision. Corneal astigmatism is measured in diopters. In routine patients who have not had had a corneal transplant, we consider 1 diopter mild astigmatism, 2 diopters moderate astigmatism, and 3 diopters high astigmatism. DALK and PK average about 4 to 5 diopters of astigmatism. A common range is 2 to 10 diopters of astigmatism. Regarding astigmatism risk, there are controllable and uncontrollable causes. The surgeon can try to sew the graft as evenly as possible to reduce risk of severe astigmatism; however, the surgeon cannot control the natural tension lines in the cornea or how symmetrically the tension lines will balance as the wound heals. Severe or irregular astigmatism cannot be corrected with glasses. Special hard contact lenses are often necessary. On average, one-third of all DALK and PK patients need hard contact to see their best due to astigmatism. Therefore, at Bennett & Bloom, we never perform DALK or PK for keratoconus patients to try to get out of contact lenses. The patient could go through all the added cost and risk of surgery only to end up where they started… or worse. DALK and PK are reserved for severe disease that cannot be fixed by contact lens wear

For corneal transplant at Bennet & Bloom Eye center in the USA or for medical tourism in the USA, contact Eyeupdate Clinic & Optical Supplies, 01 Ajuwon junction, Off Elliot bus stop, Iju Ishagah, Lagos.Tel: +2347030000001, +19093663551