Talk about a smart ophthalmoscope

Your cellphone and a 20-diopter lens can probably play a significant role in providing value to your practice.

By Tomasz P. Stryjewski, MD, MPP and Shizuo Mukai, MD

In the eight years since Steve Jobs introduced his iPhone, this small device has helped reconfigure how the world works and communicates. Smartphones and their “apps” have even proven most useful in the clinical practices of ophthalmologists.

Most commonly, we use smartphones as diagnostic tools (for testing near-acuity, contrast, or color vision, such as with the app Eye Handbook), as a drug reference (such as Micromedex Drugs) and, increasingly, and/or as an indirect ophthalmoscope.¹ For this test, we use an app called FiLMiC Pro.

Overview

Smartphone indirect ophthalmoscopy (SIO) should be an easy technique for ophthalmologists to learn because it is based on the same optical principles and techniques of standard indirect ophthalmoscopy. You achieve fundus visualization by holding a 20-diopter or equivalent lens in one hand and a smartphone in the other (Figure 1). This system works since most smartphones, including the iPhone, position the light source nearly coaxial with the device’s camera.

Figure 1. Dr. Stryjewski demonstrates technique of SIO.
IMAGE COURTESY TOMASZ P. STRYJEWSKI, MD, MPP AND SHIZUO MUKAI, MD

One app’s value

We use the FiLMiC Pro app to perform SIO because it permits us to manually control intensity of the smartphone light — we’ve found the lowest light setting works the best — exposure and focus. This significantly improves the image quality in comparison to using the native iPhone video function, which does not permit manual control of the camera’s settings. The improvement can be seen when we compare the images taken without the app to those taken with it.²

The phone records the exam as a video. Then, we can take a screenshot of the recorded video and save the still image. We edit the photo on the phone, such as cropping out the patient’s face, and transmit it via the Internet or the telephone platform. We maintain privacy since the photos have no identifying information, but we add another layer of protection by encrypting our phones.²

The LED light from the iPhone is safe in this technique. We demonstrated that the weighted retinal irradiance of an iPhone 4 LED was 1/10th that of a Keeler Vantage Plus LED.³ Our patients note that SIO is more comfortable than indirect ophthalmoscopy.

SIO’s role

At the Massachusetts Eye and Ear Infirmary, we most commonly use SIO to document findings in hospitalized inpatients or during the night when fundus photography is unavailable. Also, SIO helps to facilitate rapid communication between house officers and attendings while on call (Figures 2, 3). Peripheral retina can be imaged even with scleral depression since this is an indirect-ophthalmoscopy system (Figure 4). In one instance of superior peripheral chorioretinitis sclopetaria, the smartphone image captured the condition while an ultra-widefield imaging device did not (Figure 5).

Figure 2. Choroidal rupture after blunt trauma to the eye.
IMAGE COURTESY TOMASZ P. STRYJEWSKI, MD, MPP AND SHIZUO MUKAI, MD

Figure 3. Retinal tear well-surrounded by laser in a diabetic patient.
IMAGE COURTESY TOMASZ P. STRYJEWSKI, MD, MPP AND SHIZUO MUKAI, MD

Figure 4. Nasal ora serrata under scleral depression.
IMAGE COURTESY TOMASZ P. STRYJEWSKI, MD, MPP AND SHIZUO MUKAI, MD

Figure 5. Superior peripheral chorioretinitis sclopetaria from a BB-gun injury that was missed by an ultra-widefield imaging device.
IMAGE COURTESY TOMASZ P. STRYJEWSKI, MD, MPP AND SHIZUO MUKAI, MD

Also, SIO can help overcome media opacities that otherwise degrade the quality of standard fundus photography. Colleagues at Wills Eye Hospital in Philadelphia recently demonstrated that smartphone-ophthalmoscopy images approached the quality of traditional fundus camera photographs and exceeded them in some instances due to significant media opacities.⁴ Furthermore, by using appropriate barrier and excitation filters, ophthalmologists at Tsukuba University in Japan were able to use an iPhone for fluorescein angiography.⁵

Facilitating simplicity

We have found that medical students and non-ophthalmology physicians are often poorly skilled at using the direct ophthalmoscope. SIO could serve as a cheaper and more effective clinical tool for the nonophthalmologist. In addition, they could be useful in telemedicine applications or in global health settings in which prohibitively expensive equipment may not be available. We successfully taught our SIO technique to ophthalmologists and ophthalmology residents in Uganda and Madagascar in one-hour workshops, which enabled us to start a telemedicine system from those countries. In addition, we are working on non-mydriatic systems to make SIO even more useful. (To read more about Dr. Mukai’s work in Uganda, visit http://tinyurl.com/n9sq4k3)

Changing the physician-patient relationship

In his book “The Patient Will See You Now,” Eric Topol, MD, a cardiologist and director of the Scripps Translational Science Institute, makes bold predictions regarding patients taking charge of their own health care. More than simply serving as a platform for viewing lab results or emailing their doctor, Dr. Topol writes that patients could eventually use their smartphones to perform their physical exam. We demonstrated this proof of concept by taking a “retina selfie” (Figure 6), photographing the posterior pole using our technique.

Figure 6. Dr. Stryjewski’s “retina selfie.”
IMAGE COURTESY TOMASZ P. STRYJEWSKI, MD, MPP AND SHIZUO MUKAI, MD

Beyond self-monitoring with an Amsler grid, the next generation of technologically sophisticated patients could email their ophthalmologist a photo of their retina when vision deteriorates. Recently, Devi et al. demonstrated that by creating a smartphone-based, post-image processing system, one could subtract out the retinal blood vessels and analyze them for pathologic change, demonstrating that applications offering automated diagnostic support could one day be possible on smartphones.⁶

After a brief learning curve, an ophthalmologist can use an ordinary 20-diopter lens and a smartphone to begin taking high-quality fundus photographs and videos. Since most ophthalmologists have a 20-diopter lens and a smartphone, the only cost of this system is the FILMIC Pro app, which is under $5. We are aware of centers that are developing free apps that can do many of the controls possible with FILMIC Pro and at the same time be compatible with greater number of different operating systems. Hopefully, these will be available soon. In addition, there are disposable 20-diopter lenses that cost only $13. As designers continue evolving its technique and technology, SIO could be well poised to transform how we screen, document and monitor for blinding eye diseases. OM

REFERENCES

About the Authors
	Tomasz P. Stryjewski, MD, MPP, is a resident in ophthalmology in the Massachusetts Eye and Ear Infirmary’s (MEEI) Department of Ophthalmology at Harvard Medical School in Boston, Mass. Email him at tomasz_stryjewski@meei.harvard.edu. Dr. Stryzewski is a consultant and receives equity from Cocoon Biotech. He has no financial disclosures related to this work.
	Shizuo Mukai, MD, is an associate professor in Ophthalmology at Harvard Medical School, a surgeon in ophthalmology at MEEI, and associate scientist at Schepens Eye Research Institute. Email him at shizuo_mukai@meei.harvard.edu. Dr. Mukai perfected the SIO technique, the fundus photography described, and the technique’s safety. Dr. Stryjewski developed the technique of taking a ‘retina selfie.’ Disclosure: Dr. Mukai is a consultant for Novartis. He has no financial disclosures related to this work.