Eye Sensor/Smartphone Combo as Glaucoma Tracker

A new eye implant works with a smartphone camera to allow patients to continuously self-monitor eye pressure, making treatment for glaucoma more accurate.

Glaucoma is the second leading cause of blindness behind cataract, according to the World Health Organization.

It stems from increased intraocular pressure (IOP) in the eye, which leads to damage to retinal cells, the optic nerve and eventually irreversible blindness.

Since there is no cure, the 60 million people worldwide who are affected with glaucoma rely on regular but infrequent monitoring of their IOP by ophthalmologists to dictate treatment.

However, the caveat is that the current practice for weekly or monthly visits to the eye doctor is not that reliable. That is because IOP fluctuates during the day, depending on body posture and positioning, and other factors.

This means that the reading done by the ophthalmologist inside the office may not be the best basis for treatment.

Now, researchers have come up with a more reliable and accurate solution to monitoring pressure inside the eye.

Stanford University and Bar-Ilan University scientists developed a new eye implant that constantly monitor IOP. The device can be photographed by a smartphone camera, and an app can analyze and store the data.

The eye implant is a tiny tube that is just a few millimeters long and 50 microns in diameter, with one end open to allow eye fluid in, and the other end capped with a bulb filled with gas.

As the IOP rises, the fluid is pushed into the tube, and the gas provides resistance. The meniscus - the boundary or barrier in between - fluctuates constantly inside the tube, like in a thermometer.

The wearer of the implant can then take a photo of the device and its readings at any time, using a smartphone camera equipped with a special optical adapter. An app analyzes the image and calculates IOP.

The implantable eye sensor has:

“a limit of detection of 1 mm Hg, high sensitivity and excellent reproducibility,”

according to the study published online recently in Nature Medicine by researchers Ismail Araci, Baolong Su, Stephen Quake and Yossi Mandel.

The researchers claim that the device altered the treatment approach for 80% of glaucoma patients. The sensor also did not distort vision.

“For me, the charm of this is the simplicity of the device,”

Quake, who is a professor of bioengineering at Stanford University, said in a statement.

“Glaucoma is a substantial issue in human health. It's critical to catch things before they go off the rails, because once you go off, you can go blind. If patients could monitor themselves frequently, you might see an improvement in treatments." 

“We believe this self-monitoring capabilities of the implant can significantly enhance the treatment and make it significantly better for the patient,”

Mandel, who is head of the Ophthalmic Science and Engineering Laboratory at Bar-Ilan University, told Fortune.

Glaucoma experts not involved in the study believe that the new device is a significant advance for glaucoma monitoring and treatment.

The main advantage the eye sensor offers is 24/7 monitoring that can be recorded and reported by the wearer at any time, and from anywhere.

“Continuous monitoring is a clear unmet need in glaucoma,”

Francesca Cordeiro, a glaucoma researcher at University College London, told New Scientist. 

The device as currently designed can be implanted with standard intraocular lens prosthetics used for cataract patients. The researchers are planning to eventually use newer materials and techniques for the eye sensor to be implanted on its own.

“If patient comes in for cataract surgery and, if at the same time you can implant the device that would allow monitoring IOP more accurately and remotely, that has a huge benefit,”

Dr. Andrew Iwach, chairman of board for the Glaucoma Research Foundation and executive director Glaucoma Center of San Francisco, told Fortune.

Eye sensors are among the next wave of wearables and mHealth solutions that can make a huge impact in personal health monitoring. Sensimed also makes a device called Triggerfish that measures continuous ocular dimensional changes over 24 hours.

Meanwhile, Google is partnering with Novartis in developing its smart contact lens that can read glucose levels using tears.