Femtosecond Laser May Reduce Risk of Myopic Regression after LASIK

A significant fraction of LASIK patients may experience myopic regression after LASIK. When this occurs, the results of LASIK will decline toward increased myopia (nearsightedness) after treatment. It’s not known exactly what is the frequency of this condition, but some studies have suggested it might be as high as 20% during the first six months and as high as 25% after a year. Patients with high myopia (at least 10 diopters) are at the greatest risk for this complication.

A recent study suggests that the use of the microkeratome may be partly to blame for this, and that LASIK patients may be more likely to retain the quality of their LASIK results if the procedure is performed using a femtosecond laser. The study, published in the Journal of Cataract and Refractive Surgery looked at the long-term results of 786 LASIK patients, 377 who had LASIK performed with a microkeratome, 409 performed with a femtosecond laser. Follow-ups were performed for both groups at one week and 12 months after surgery.

Researchers defined myopic regression as a combination of a myopic shift of 0.5 diopters (about 1 line on the Snellen chart) or more with residual myopia of 0.5 diopters or less. Using this definition, the risk for myopic regression after LASIK with a microkeratome was 67%, compared to 44% risk for femtosecond laser LASIK.

This study is part of the growing body of evidence that, although subtle, femtosecond lasers may actually result in significantly better LASIK results than microkeratomes.

To discuss a possible LASIK procedure with a doctor, please contact a local ophthalmologist.

SMILE Eye Surgery Offers an All-in-One Alternative to LASIK

Since LASIK is more than two decades old at this point and has several drawbacks despite its proven results, it should not be a surprise that people are always looking for a new alternative procedure. The new candidate is called SMILE surgery, which is short for Small-Incision Lenticule Extraction surgery, and it uses only a femtosecond laser to reshape the cornea.

This procedure hopes to remove flap complications associated with LASIK as well as the risk of dry eyes after the procedure, and maybe give a treatment alternative to many people who cannot benefit from LASIK.

In SMILE surgery, a small incision is made in the surface of the cornea using a femtosecond laser. The femtosecond laser is then used to cut out a lens-shaped section from the interior of the cornea. This section is then extracted using a small tool.

There have been a number of significant studies performed on this procedure. One of the earliest was performed in Germany and the results published in the Journal of Cataract and Refractive Surgery in 2008, using a slightly different version of the procedure called Femtosecond Lenticule Extraction (FLE, sometimes FLEX or reFLEX). This study treated ten myopic eyes, with 90% of them achieving +/- 1.00 D, approximately equivalent to 20/50 vision. The study showed no evidence of higher-order aberrations.

A more recent study published in the British Journal of Ophthalmology looked at 91 eyes of 48 patients. This multi-center 6-month prospective study showed even more positive results, with 95.6% of patients within 1.00 D, and 83.5% of eyes achieved an uncorrected visual acuity (vision without glasses or contacts) of 20/20 at 6 months, comparable to LASIK results. In the follow-up questionnaire, 93.3% of patients were satisfied and would undergo the procedure again.

The SMILE procedure is already being offered in Britain and India, and researchers are recruiting candidates for clinical trials here in the US. It’s hard to say just how long it will be before the procedure will be available.

To learn more about advanced vision correction alternatives, please contact a local ophthalmologist today.

Pentagon Orders Prototypes of Advanced Optic Contact Lenses

The US military is the first customer for an advanced optic contact lens designed to give soldiers a much better view of the battlefield while using heads up display (HUD) units. The two-part system is designed to replace the current HUD units which are bulky and are limited in effectiveness by the soldiers’ limited field of vision.

These advanced optic contact lenses, designed by Innovega, a Washington, DC technology company, are multifocal lenses, like the advanced IOLs ReZoom, ReStor, and Tecnis. But the IOLs work by bringing a plurality of images to the retina, only one of which will be focused and therefore seen by the user. The contact lenses, on the other hand, work by bringing a plurality of focused images to the retina, allowing the user to focus on multiple objects at different distances all at once. For this specific application, the lens allows a soldier to focus on the HUD as well as on the rest of the battlefield.

How It Works

These multifocal lenses are divided into two zones. The internal zone sends light from the HUD toward the middle of the pupil where it can be conveyed to the macula, the zone on the retina responsible for detailed vision. The outer filter focuses light from the surrounding environment to the pupil’s rim.

This dual-focus display allows people to focus on multiple things at once, something human beings are not normally able to do.

The Frontiers of Augmented Reality

In addition to the military application, executives at Innovega hope to begin marketing the lens to the public, potentially as soon as 2014. The lenses have a number of potential applications, such as allowing 3-D interfaces by allowing different images to be projected onto each lens. This could be used for movies, or for immersive gaming.

The lenses could also be a solution to distracted driving, allowing drivers to focus simultaneously on the road as well as their car’s instrument panels, allowing them to perform a wide variety of tasks without taking their eyes off the road.

The Innovega display system is also seen as a potential competitor to Google’s Project Glass, which would allow people to view personal HUDs while walking around city streets and automatically see information about businesses and other local services.

This could also be utilized by law enforcement and security if integrated with the new Ex-Eye system being implemented in Spain. The Ex-Eye system uses advanced facial recognition to scan up to 100,000 faces per second, flagging known criminals and suspected terrorists to stop them before they are able to execute their plans. This security technology will be implemented at the 2016 Olympic games in Brazil, and it may be able to be significantly more effective if combined with Innovega’s advanced contact lenses.

Cautious Optimism

Although Innovega is justifiably excited about their display units, we should be a little more skeptical. Previous experience with trying to impose multiple viewpoints has met with mixed success. LASIK monovision and multifocal lenses give good results for some people, but others experience disorientation, motion sickness, and a significant fraction of users are unable to adapt to their plural visual system.

To learn more about advanced lenses that may be able to help your vision today, please contact a local ophthalmologist today.

Electronic IOL May Be the Future of Cataract Surgery

A computer-controlled, fully programmable intraocular lens (IOL) may soon give cataract surgery patients better vision than any time in their lives. One of the persistent problems in cataract surgery is properly calculating the strength of lens to be used for optimal results. Even experienced ophthalmologists find this to be challenging, and subtle, unknown factors can lead to uncertainty in the final results. In about 1-2% of cataract surgeries, the results are so bad that the patients seek reoperation, and most often this is to have a different lens implanted. Many other patients live with less-than-optimal vision, or have secondary refractive procedures (such as LASIK) to improve the results.

The electronic IOL, known as ELENZA, may eliminate that problem, as well as possible problems that may result from future changes in vision. The new IOL is fully programmable, so it can be adjusted not just immediately after cataract surgery, but at a later date in response to eye injury, glaucoma, or other visual changes. The lens is also self-accommodating, so it does not depend on potentially weakening cilia muscles, and it may even be able to surpass the accommodating ability of the eye’s natural lenses. Theoretically, the lens could be used to give its recipients telescopic vision and super visual clarity at all distances.

You may remember the LED contact lens that was announced last year. In talking about that concept, I discussed the possibility of IOLs that replace the natural lens with an LED-array. Essentially, that would involve replacing the transparent lens with an opaque camera-transmitter array, like having a tiny video camera on one side and a tiny TV on the other.

This new electronic lens is different–it still functions like a lens, only it uses liquid crystal as the refractive medium. The arrangement of liquid crystal can be controlled by small electromagnetic fields, which in this case is used to change the refractive index and therefore the focusing power of the lens. The concept has already been applied to prescription glasses, allowing the wearer to change the focus of the glasses, eliminating the need for bifocals.

One problem with electronic lenses is that they need a power source. In the case of ELENZA, developers project the power will be provided by a microscopic rechargeable lithium-ion battery. Although similar to the batteries used on cochlear implants, they will be even smaller. These batteries will need to be recharged every 3-4 days, though developers estimate their lifespan at 50 years. Chargers, they say, can be placed in pillows or in face masks worn while sleeping.

One advantage of the liquid crystal lenses over the LED display is what happens if your batteries fail. In the liquid crystal lens, it simply reverts to a monofocal lens that gives you good distance vision, suitable for driving a car and most other outdoor tasks. The LCD display, on the other hand, would simply go dark, leaving you blind.

It remains to be seen, though, whether these new implantable lenses could be synced with a computer to give you an implanted display.

The developers of ELENZA hope to begin in vivo studies in the near future, possibly as early as 2013, and hopefully FDA approval as early as 2018.

There are still a number of good IOL options for people seeking cataracts today. To learn more about your IOL options, please contact a local ophthalmologist for a consultation today.

Will Phakic IOLs Be Approved for Hyperopia?

Phakic IOLs are a type of intraocular lens that is used to help your eye attain the proper focus. Unlike the lenses used in cataract surgery, which are sometimes called aphakic IOLs, these lenses do not replace your eye’s natural crystalline lens. Instead, they are helper lenses, sometimes described as “implantable contact lenses.”

Phakic IOLs have been approved for the treatment of myopia by the US Food and Drug Administration (FDA) since 2003. However, they have not been approved for the treatment of hyperopia. According to industry representatives, studies of phakic IOLs for treatment of hyperopia are ongoing, but will they ever be approved?

Concerns with Phakic IOLs for Hyperopia

There are two significant concerns that have delayed the approval of phakic IOLs for hyperopia. Both relate to the narrow anterior chamber of hyperopes, the part of the eye between the iris and the cornea, where some phakic IOLs are placed. First, there is concern that the IOL will abrade the endothelium, the innermost layer of the cornea, which could result in a condition similar to Fuchs’ Dystrophy. Second, there is concern that implantation of a phakic IOL in an already crowded anterior chamber could increase the risk of closed angle, or acute glaucoma.

Both of these risks are likely very rare, but because of the seriousness of the conditions, even a small risk merits significant study before approval.

Some Study Results

In the early clinical trials, phakic IOLs were being studied equally for both myopia and hyperopia. It was concluded that phakic IOLs should only be placed in the posterior chamber, behind the iris. These early studies confirmed that risks associated with phakic IOLs were small, but also showed that the results were not highly predictable.

However, a recent Italian study of 59 eyes with posterior chamber placement of phakic IOLs showed significant results. The study looked at the patients’ results at several points up to ten years after implantation. It showed that people received the phakic IOLs achieved, on average, a spherical equivalent of +0.07 diopters, essentially 20/20, though one eye did lose one line of best corrected visual acuity. Visual acuity was stable over the ten-year period. Endothelial loss was slight, and did not increase. Intraocular pressure increased by about 5.3%, and there was one incident of closed angle glaucoma.

Overall, though, this more recent study suggests that the path should be clear for approval of phakic IOLs.

Market Concerns

The main barrier to approval of phakic IOLs for hyperopia is likely market-based. In addition to potentially increasing risks, the narrow anterior chamber of hyperopes makes implantation of the IOLs more difficult for surgeons. This makes them less popular among surgeons. With other treatment options like LASIK and PRK available, surgeons do not seem to be crowing for phakic IOLs for hyperopia treatment. With no extant market, it seems unlikely that companies will be making the big push for approval of phakic IOLs for hyperopia any time soon.

If you want to learn more about phakic IOLs or other types of refractive eye surgery, please contact a local eye doctor today.

LED Contact Lenses: Future Computer Display or High-Tech Dead End?

Last week, researchers from the University of Washington and Aalto University reported that they had designed, constructed, and tested in vivo an LED contact lens display. The display was powered wirelessly and consisted of only a single LED light, but it could be controlled by computer. Although the initial test model was only a single pixel, researchers claim that they have already developed a micro-Fresnel lens that would allow multiple-pixel displays to be clearly discernible by a wearer. Although some think that this technology might represent the next phase in the evolution of ever-more personal computing, the visual equivalent to the Bluetooth earpiece that will allow people to use their smartphones without actually looking at the display, I believe that experience with contact lenses has taught us this technology is likely a dead-end that will, at best, have a few years of faddish popularity.

First, let’s consider what researchers have accomplished. They created an LED display on a contact lens. To accomplish this, they put wiring to serve as an antenna that can receive signals and channel power to the LED. When the lens was sitting in free space, it could be powered from up to three feet away, but when it was on the eye, its effective range dropped to less than an inch.

The lens itself is made of polyethylene terephthalate (PET to you and me), because it is chemically resistant, thermally stable, and transparent. However, PET is a terrible material to make contact lenses out of because it is hard and doesn’t allow airflow to the eye, so you’d only be able to use the lens for a few minutes at a time. And since the surface of your eye is actually too close to allow you to focus on the display, it would require a series of micro-Fresnel lenses to focus light from the display. Invented in 1822 by French physicist Augustin Fresnel, Fresnel lenses use concentric prismatic structures to capture and refract light in the intended direction. Testing of the micro-Fresnel setup showed that it could be used to separate the incoming light into a tiny 3×5 array on the rabbit’s retina.

But despite the apparent promise of this technology, I personally do not think it will have much success. Let us assume that many of the limitations of the initial research model will be overcome, that the contact lens will be able to be made as comfortable and effective as regular contact lenses–their popularity will still be limited. Why? Because contact lenses are so inconvenient and uncomfortable that they have driven hundreds of thousands of people to LASIK.

If you are a contact lens wearer, you know about the limitations of contact lenses, the irritation of the eye, and the necessity of cleaning the lenses. Even with regular cleaning, contact lenses are prone to develop bacterial films, which can in turn lead to vision-threatening eye infections. Disposable contact lenses are for that reason the norm, but if your contact lens was printed with possibly hundreds of dollars worth of circuitry, would you really want to get rid of it, or would you be more likely to cheat and take the risk of eye infection?

And what if you lost one of these contact lenses at a party or when walking down the street? How often do you actually find the lens, and how often does it end up lost? Now, again, imagine that that lens has several hundred dollars of circuitry printed on it.

Better solutions for integrated visual displays already exist. For example, researchers in 2005 reported a method that involves replacing the eye’s natural lens with an LED-array that is capable of projecting visual data onto the retina. The implanted array could be designed to switch between rebroadcasting visual data received on the back of the lens and a computer display.

An even more promising option, I believe, is to bypass the eye altogether. Subretinal implants have been shown to be able to stimulate the central visual system directly. Although these are currently being studied to restore sight to the blind, once perfected they can be used to transmit any kind of visual data to the optic nerve, including a computer display.

However, any of these techniques is likely a decade or more from implementation, and time will tell which approach proves most practical.

Anti-VEGF Reportedly Better than Lasers in Preventing Recurrences of Retinopathy in Prematurity

Houston, TX – Scientists at the Robert Cizik Eye Clinic at the University of Texas Health Science Center at Houston-Medical School have found that using intravitreal injections of bevacizumab are better than conventional laser therapy for the prevention of recurrences of retinopathy of prematurity (ROP). Using intravitreal injections also avoids some of the complications that come with laser treatment.

Bevacizumab, an inhibitor of vascular endothelial growth factor (VEGF), has been used more frequently as an off-label treatment for ophthalmologic neovascular disorders, such as ROP and the wet form of age-related macular degeneration.

According to the authors of the study, this is the first time a controlled trial of ROP has taken place. They picked patients who were the most vulnerable and had the worst cases of the condition. The study compared the two treatments for stage 3+ ROP in zone I or zone II. Zones indicated the area of vascularization. Zone I stage 3 is the hardest to treat, and has a higher rate of recurrence. Stage 3 ROP is when treatment usually begins, and stage 3+ means the “dilated veins and tortuous arteries” are in at least two quadrants of the eye.

The Trial

There were 15 different centers participating in the trial and used 150 infants 30 weeks old or younger. They were randomly given either intravitreal bavacizumab or conventional laser therapy. Almost 70 of the infants had zone I disease; the others had zone II posterior disease.

The primary outcome of the study was focused on recurrence, and showed 26% of the infants given laser therapy compared with only 6% of the infants given bevacizumab. The risk reduction was 83% when using bevacizumab.

The maker of bevacizumab, Genentech, does not plan to seek FDA approval for its use for treating ROP, nor will it be promoted for use for any ocular disorder.

If you would like to learn more about this, please find an experienced ophthalmologist through eyes.com today.

Newly Developed Implant Treats Macular Edema

Five out of every 1000 people over the age of thirty will suffer from some form of RVO (retinal vein occlusion). In RVO, the retinal vein becomes blocked (occluded), causing fluid to build up in the retina and the macula to swell and thicken. This thickening, called macular edema, can cause severe vision loss.

Because of the swelling in their eyes, people with macular edema have trouble with everyday activities like reading, watching TV, and driving. People with RVO have many direct medical costs from this condition, but they also have indirect costs such as loss of income. Previously, procedures such as surgery and laser photocoagulation have been used to treat RVO and macular edema, but these are not always effective.

There is good news, however. Allergan, Inc., a company devoted to developing pharmaceuticals for commercial use, has released a product called Ozurdex which has been clinically proven to treat RVO. Ozurdex is a tiny rod-shaped implant which doctors inject directly into the eye. The rod dissolves and releases dexamethasone, a steroid that reduces inflammation in the eye.

When compared with a placebo, Ozurdex significantly improved patients’ vision and reduced swelling. Research shows that after 8 weeks, 43% of the people who received Ozurdex had vision improvement of at least three lines on an eye chart, and 47% were considered inflammation free.

Ozurdex will help many people suffering from RVO, as well as those affected by diabetic retinopathy, a similar disorder common in diabetic patients. If you have been diagnosed with RVO or diabetic retinopathy, please contact an ophthalmologist near you to discuss your treatment options and to set up an initial consultation today.

Exciting New Product Developed for the Treatment of Age-Related Macular Degeneration

Exciting New Product Developed for the Treatment of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a disease affecting millions of Americans, and is the leading cause of blindness in Americans and Europeans over the age of 65. As the eye ages, abnormal blood vessels grow behind the retina and leak blood and fluid, causing the retina to malfunction, which leads to blindness. Previously there were no treatments to reverse the damaging effects of this disease. Now, however, a new technology developed by pharmaceutical company Regeneron promises to provide hope to all those suffering with AMD.

Regeneron partnered with Bayer HealthCare to develop and commercialize a product called VEGF Trap-Eye and began testing the product’s effectiveness in 2007. Despite the slightly lethal-sounding name, VEGF Trap-Eye has proven itself to work wonders in tests, improving visual acuity in the majority of people who received the product.

What Is VEGF Trap-Eye?

VEGF Trap-Eye is a man-made protein designed to fuse to natural proteins in the human body. It has been engineered to bind to VEGF (vascular endothelial growth factor) which is one of the proteins involved in AMD. VEGF naturally occurs in the body and is needed to support tissue and organ growth by triggering the growth of blood vessels. However, this is the protein that causes those harmful blood vessels to grow behind the retina. When VEGF Trap-Eye binds to this protein, it renders it unable to create any new blood cells, preventing AMD.

Now We Wait

Though tests have affirmed VEGF Trap-Eye’s success with treating AMD and other conditions that affect the retina, such as central retinal vein occlusion (CRVO), Regeneron is awaiting a meeting with the FDA’s Dermatologic and Ophthalmic Drugs Advisory Committee on June 17, 2011 to see whether they can begin marketing this product in the U.S. If the FDA gives the okay, the millions suffering from AMD and other eye problems may find relief at last.

If you have more questions about age-related macular degeneration or treatment options, contact an experienced ophthalmologist in your area today.