Earlens® is a rechargeable hearing aid system that provides amplified sound in a very unique way; while most hearing aids drive the eardrum with traditional acoustic amplification, Earlens drives the eardrum with direct mechanical vibrations. Direct-drive amplification, enabled by a vibrating “lens” placed on the eardrum, is capable of meeting the needs of those with mild to severe sensorineural hearing loss, but there are some pros and cons of the unique technology you should be aware of.
The Earlens system and the Earlens Control smartphone app.
The Earlens System
The core of the Earlens system consists of a vibrating tympanic lens, a custom-fitted canal mold (“ear tip”), and an ear-worn sound processor. Additional components include a hearing aid charging station and the Earlens Control smartphone app.
The Earlens system is fit in cooperation between an otolaryngologist (ENT) physician and an audiologist. The ENT examines your ear and, along with your audiologist, determines candidacy, takes a deep canal impression of your ear canal and fits the custom tympanic lens. Your audiologist then programs the processor and assists you in your orientation to the Earlens system.
The price of Earlens varies by provider, but is likely to be within the range of $8000-$10,000 for a pair. The cost puts Earlens a few thousand above most traditional premium hearing aids, but the company claims to provide a superior product (we’ll talk about this) and premium concierge service.
Dr Cliff reviews the new Earlens inductive hearing aid system, which replaces the previous light-driven Earlens system. Closed captions are available on this video. If you are using a mobile phone, please enable captions clicking on the gear icon.
The entire Earlens system is intended to have a lifespan much like that of a traditional hearing aid, that is, approximately 3-5 years. The system comes standard with a 3-year warranty which covers repair and/or replacement of the device due to malfunction during the 3-year period. Should the lens or processor be lost, this would also be covered during the warranty period.
The tympanic lens
The tympanic lens is a custom device that floats on your eardrum (tympanic membrane) using a thin layer of mineral oil, much like a typical contact lens. The lens must be custom-fitted to your unique eardrum to enable surface tension adhesion, and to ensure the lens remains comfortable.
In order to create a custom-fitted lens, an ENT physician will take a deep ear canal impression in-office. This is done under a microscope and without the need for any anesthesia. It’s a simple in-office procedure that takes approximately 30 minutes. According to the company, most people (86%) have no issue with the impression taking. From this impression, the custom eardrum lens and ear tip are produced.
Once placed, the tympanic lens directly vibrates the eardrum providing direct-drive mechanical amplification. Vibrations are produced by a tiny motor on the lens and transmitted through a small bone (the malleus) on surface of your eardrum. Earlens claims that there is no physical sensation produced by wearing the lens on the eardrum.
The Earlens Lens directly vibrates the eardrum providing direct-drive mechanical amplification.
The tympanic lens is worn 24/7 after placement and is worn while sleeping as well as bathing/showering. You can even swim with the lens in place but wearing swim plugs is highly encouraged especially if you plan on swimming at any depth or swim regularly. Note, the processor is worn only during normal waking hours—not usually while sleeping and it is not intended for use while swimming or bathing.
The Earlens behind-the-ear processor
The Earlens processor looks and acts much like a traditional behind-the-ear (BTE) hearing aid and like many hearing aids on the market today. Here are a few of its features:
- Multi-channel compression and frequency shaping (20 channels)
- Up to 60 dB of gain (amplification) across the frequency range from below 100Hz to 10kHz
- Rechargeable battery
- Adaptive directional microphones
- Noise reduction algorithms
- Multiple programs – up to 4
- Push buttons on device to control volume, program change and power on/off
- iPhone compatibility allows direct streaming of phone calls and audio
- Available iPhone app
Within the Earlens system, the job of the processor is to pick up sound, process it and then deliver the signal via a cable to the ear tip. This is where Earlens departs from the ordinary.
The custom ear tip
The custom Earlens ear tip receives the information from the processor and converts the digitized sound signal to a low-energy wireless signal, also called inductive or radio signal, which is then transmitted from an antenna coil in the ear tip to the lens resting on the eardrum. This wireless signal contains both the desired audio information and the power necessary to create tiny yet precise mechanical movements of the lens and then your eardrum. The movements or vibrations of the eardrum are transmitted through the middle ear system to the cochlea and are what provide the amplification of the system. The custom ear tip is highly vented and made of soft silicone which is intended to provide a comfortable fit both physically and acoustically.
The Earlens ear tip is custom fitted to your unique ear canal. The tip transmits sound in the form of inductive radio signals to the lens, where radio energy is converted into mechanical vibrations on your eardrum.
In the previous generation of the Earlens product a light source was used to transmit sound and power to the lens on the eardrum. This light source was highly directional, meaning that the alignment of the light tip in the canal relative to the lens on the tympanic membrane had to be maintained in order for the system to function properly. In some people, when talking or chewing, the ear canal can move quite a bit, which would cause an intermittency in the signal. In this new generation utilizing an inductive (radio) signal, this problem has been overcome as the signal is not directional.
The hearing aid charger
The Earlens charger works like many other wireless chargers on the market. The processors are placed in the charger for 4 hours to complete a full charge cycle and the processors should provide 16-24 hours of use on a single charge. The life expectancy of the rechargeable system is approximately 3 years.
Earlens instructs patients to firmly press the behind-the-ear processors into the slots to initiate charging.
The Earlens Control app
The Earlens Control app is available for iPhone and allows for control of volume, program change, bass/treble control, reminder settings, support videos, and access to concierge services. Earlens notes that recent improvements to the app make it more intuitive as well as providing a built-in connection to the concierge team. The app also provides the ability to use your iPhone as a remote microphone. Please note that if you are utilizing an Android phone, an application is not available at this time but is said to be in the works.
Less feedback and richer sound
As noted above, once you are fitted with the EarLens system, the tympanic lens directly vibrates the eardrum, providing mechanical amplification—not acoustic. There are a few advantages of this approach.
First, because no sound is produced by the lens itself, there is a low likelihood of acoustic feedback. Feedback is the annoying high-pitched squeal that occurs when amplified sound is picked up by the microphone (of a traditional hearing aid) and re-amplified in a continuous loop. Historically, feedback has been a major issue for hearing aids.
While digital feedback reduction algorithms work well, and eliminate feedback in most hearing aids, there are limits, especially in modern “open” fitting hearing aids (where sound easily leaks out of the ear canal). This is a big advantage of the Earlens system—because there is no acoustic amplification, the potential for feedback is much more limited. This means ample high-pitch amplification can be provided much more readily.
Through direct-drive amplification, the Earlens system also provides more bass than open-fitting hearing aids. When the ear canal is left open, bass tones easily leak out of the ear, leaving the user with a thinner, more high-pitched sound. Losing the bass can have a big impact on the sound quality of music, but can also make speech sound less natural. Earlens overcomes this by driving bass tones directly through the eardrum with mechanical vibrations.
Closed fittings (traditional hearing aids with closed domes or custom molds) can also be a problem. While a more closed fitting does allow for more bass (less bass leakage), many people will not tolerate this as their own voice may sound unnatural, or their ears can feel plugged up. Often, a compromise has to be made by increasing venting, which leaves the ears feeling more open, but again causes a loss of bass tones. Earlens seems to offer the best of both worlds in the sense that it leaves your ear canals open without any loss of bass for amplified sound.
The end result for Earlens is an increased audible bandwidth. That is, a wider range of pitches can be provided since low pitch acoustic sound doesn’t leak out of the ear (with venting) and high pitches can be provided without the fear of feedback.
More bandwidth than traditional hearing aids
Normal human hearing is measured within the pitch range of 20 Hertz (Hz) to 20,000 Hz. According to Earlens, their system provides amplification that listeners in the fitting range can actually use, over a frequency range from approximately 125Hz out to 10,000 Hz. A more traditional hearing aid, if vented enough to be considered “open”, will provide a usable range of approximately 800 Hz to 5000 Hz. If unvented, the range increases to approximately 250 Hz to 7000 Hz, depending on the hearing aid, how it’s programmed, and the physical characteristics of your ear.
Earlens vs a number of popular open-fitting hearing aid models. Simulated in-situ OSPL for open canal, 65 dB pink noise stimulus, 1/3 octaves.
It should be noted that many manufacturers indicate that their hearing aids provide a frequency response in the range of 100 Hz to 10,000 Hz. While this may be possible in a test box, sufficient amplification likely won’t be available for most people at the high and low end of the pitch range. This is again due to the issues related to bass leakage and acoustic feedback, but also the result of “frequency roll off”—hearing aids typically provide peak amplification in the mid-pitches (around 2000Hz or so) and then roll off, providing less amplification in the highest pitches.
A broader frequency response, obviously, provides a richer and more robust sound to the listener but may also help to provide better speech understanding particularly in complex listening situations. In other words, the more frequencies represented, the more redundancy there is in the signal which is especially useful in noisy environments like a restaurant.
Earlens concierge service
Another somewhat unique characteristic of Earlens is how the company approaches customer interactions. The company tries to cultivate a relationship with you, the end user, in the hopes of ensuring a positive experience. This is done via remote support and a concierge team at Earlens which is available for the life of the hearing aid. Most traditional hearing aid companies provide no (or very limited) direct support to end users. So, in between visits to your audiologist or ENT, you can reach out to the Earlens concierge team for answers to your questions, troubleshooting, etc.
Who can use the Earlens system?
Not everyone is a candidate for this device and you should discuss your candidacy with your ENT physician or audiologist if you are considering purchasing the Earlens system. First, your hearing loss must fall within the fitting range seen here:
Earlens fitting range
As you can see, the fitting range can accommodate a wide range of hearing losses from mild to severe. However, even if your hearing loss falls within the range, there are other considerations and restrictions to consider:
- You should have good word understanding; the company recommends a score of greater than 50% at your most comfortable listening level (MCL).
- Your ear canal anatomy has to be able to accommodate the device. That is, if you have an extremely narrow ear canal or one that angles sharply you may not be able to wear the device. However, the company notes that they can fit more than 90% of ear canals.
- If you have been told you have exostoses, which are bony growths in your ear canal, you are likely not a candidate for Earlens.
- You must have a healthy eardrum and middle ear; this will be evaluated by your ENT and audiologist.
- You need to be compliant with the instructions of use including regular application of mineral oil to the ear canals to help the lens to stay in place. So, for example, this would not be a good choice for someone with memory issues and/or dexterity issues where administration of the oil would be difficult.
- You must be able to tolerate ear cleaning and impression taking.
- The device is also not recommended for those who have had a sudden hearing loss or have fluctuating hearing loss or for those with an immune system issue that may affect the tissue in the ear canal or eardrum.
Benefits of the Earlens Contact Hearing Aid
- Unique approach to hearing loss treatment providing a medical model treatment plan utilizing both an Audiologist and an ENT physician
- An extended bandwidth amplification system with excellent sound quality for appropriate candidates
- Concierge approach to care
- Company notes research verified benefits (here, here, and here) of enhanced speech understanding, reduced listening effort, and superior sound quality
- Feedback essentially a non-issue with the device
- Rechargeable system with good battery life
- Portability of care without additional cost through company’s premium service plan
Limitations of the Earlens Contact Hearing Aid
- Cost may be prohibitive for some
- Multiple steps across multiple professionals
- More investment in care of device with requirement for regular applications of mineral oil to the ear canal, as well swimming precautions
- Limited color choices
- Connectivity options limited; not compatible with Android devices though company notes this is in the works
- With lens in place but not utilizing processor, lens dampens hearing slightly (approximately 4 dB)
- Not appropriate for profound hearing losses or for children
- Product is not widely available at the moment as Earlens is dispensed with an ENT and Audiology partnership model
The Earlens device is an innovative way to treat hearing losses and can provide a very broad frequency response to the listener. This results in excellent sound quality that is unlikely to be seen with traditional hearing aids utilizing an acoustic amplification approach. In turn, this can lead to better understanding of speech especially in difficult listening situations, reduced listening effort and improved overall acceptance of amplified sound. However, those benefits do come at a cost both with what you’ll pay for the device as well as the time investment with the number of visits and care that are required. As always, discuss all of your hearing healthcare options with your physicians, Audiologists or other hearing healthcare provider.