Across all subspecialties, the field of ophthalmology continues to grow technologically with promising advances aimed at the health of the eye and socket. This article focuses on 5 of the top technologies that ophthalmologists have their eye on and that I find very interesting.
1. VisionCare's Implantable Miniature Telescope
VisionCare Ophthalmic Technologies recently received FDA approval for their implantable miniature telescope. This monocular implant is designed for patients with end stage age related macular degeneration and was part of the CentraSight treatment program. The implant is about the size of a pea and is inserted behind the iris. The implant enlarges images and projects these images on healthier areas of the retina. It does not repair the damaged macula, but rather magnifies objects in the area of central vision while the un-Implanted eye provides peripheral vision. This device not only offers patients improved visual acuity, but also improved quality of life. Clinical trials have proven successful and results have already been published in many peer-reviewed journals. VisionCare, a California based company, will plan on conducting post-approval studies to monitor patient outcomes.
2. Optovue iVue Optical Coherence Tomography
Optovue, a California based company, received FDA clearance for the iVue compact spectral domain optical coherence tomography unit, the successor to the RTVue system. The iVue offers the same scanning speed and resolution as the larger RTVue system, resulting in high speed, high resolution scanning and reports of the retina, retina nerve fiber layer and cornea. This unit operates on a standard slit lamp-like base and is comprised of a scanning head that is only 4.5lbs, a control module, laptop PC and foot switch.
3. Orbital Tissue Expander
The Orbital Tissue Expander (OTE), developed by Dr. David Tse in Miami, FL and manufactured by Innovia LLC, was one of the three winners of the 2010 Medical Design Excellence Awards in the Implant and Tissue-Replacement Products category. This product, made from biocompatible, inflatable silicone, is ideal for children with anophthalmia, microphthalmia, or who have lost an eye to trauma or infection. The implant is positioned in the orbit and held in place by a titanium fixation plate that is anchored to the lateral orbital rim. Central and anterior is an injection port through which a 30-gauge needle is inserted and saline is injected to expand the implant to a final volume of approximately 5cm3. After serial injections, the gradually enlarging implant will exert pressure on the orbit to stimulate growth of the bone, allowing the affected socket to grow with the normal contralateral socket, preventing facial asymmetry. Implantation of the OTE obviates the need for multiple surgeries often necessary in children to exchange an implant for a larger one. The OTE has been successfully implanted in several children in the first clinical series.
4. Vitamin E Infused Contact Lenses
Researchers at the University of Florida in Gainesville developed vitamin E infused contact lenses. This powerful antioxidant is packaged in clusters within the contact lens and is slowly released onto the eye. The vitamin E structures act like ‘nano-bricks’ through which drug particles cannot pass, but rather must go around. These nano-bricks are so much larger than drug molecules (few hundred times bigger) and they create an obstacle course for the drug molecules so that they must travel a much longer path. This increases the duration of the drug release from the lens and exposure to the eye. In animal tests, the vitamin E infused contact lenses administered drugs up to 100 times longer than most commercial lenses. These lenses can be designed for continuous wear up to one month. These lenses can be used to treat glaucoma as well as other eye conditions such as cataract and dry eye. Not only will these lenses prolong delivery to the eye, but also they should decrease systemic absorption and thus systemic side effects that can be seen with anti-glaucoma medication. Vitamin E is a proven nutraceutical that in small amounts is good for the eye. This vitamin also blocks UV light without any reduction in transparency, making this vitamin not only beneficial for treatment of disease, but prevention as well. Although these lenses are not currently on the market because further clinical trials are necessary, this technology will be something to look out for in years to come.
5. Retinal Implants
There are two main approaches to retinal implants: subretinal and epiretinal and many companies around the world are working on various models using both approaches. The subretinal approach involves implantation in the macular region. By implantation beneath the retina, the natural direction of light processing is maintained. The epiretinal approach also involves placing the chip in the macular region, but requires additional equipment, such as cameras or special glasses, to function properly. Three retinal implants are discussed below.
Retinal Implant AG
Retinal Implant AG, a German company, recently announced results of its first human trials using a subretinal implant in patients with retinitis pigmentosa. This implant consists of a stimulation chip with 1500 electrodes on a polylmide film to which energy is delivered via a retroauricular plug. Eleven patients underwent a transchoroidal implantation of this chip. Patients noticed over time a significant improvement in their vision. All but one implant was explanted per protocol at one or three months and all patients tolerated the implant well.
Argus II Retinal Prosthesis
This second-generation epiretinal implant is a 60 electrode artificial prosthesis developed by Lawrence Livermore National Lab and currently in trials by Second Sight Medical of Sylmar, California. There are three main components of this artificial retina: (1) the thin-film electrode array that contains the neural electrodes, (2) the biocompatible electronics that stimulate the retina and provide wireless power and communication, and (3) the necessary surgical instruments for proper implantation. This implant works in conjunction with an external camera and video processing system to provide a rudimentary form of sight. Patients should recognize objects faster with this second generation design as compared to the first generation. The company is now working on a third generation product. Argus II was chosen by R&D Magazine for the 2009 R&D 100 Award as one of the most innovative technologies in science.
Researchers at MIT are working on a retinal implant that works in conjunction with a special pair of glasses that have an embedded camera that wirelessly transmits signals to a microchip in the retina.
These image signals are then transmitted to the brain. The microchip, which is encased in titanium to prevent corrosion, has receiving coils that surround the globe. Early tests showed that retinal stimulation could produce a small amount of organized vision. The company is now conducting further studies using a design that will attach to the outside of the eye and the electrodes will be implanted behind the retina.