How iPhone may replace slit lamp photos

August 15, 2013

In comparing conventional slit lamp photography with iPhone images, it was found the smartphone produces higher quality pictures and in a more economical way.

Take-Home

In comparing conventional slit lamp photography with iPhone images, it was found the smartphone produces higher quality pictures and in a more economical way.

 

Acute intraretinal hemorrhage from a choroidal neovascular membrane in exudative age-related macular degeneration. Taken using an iPhone 5 and standard camera app with a Volk digital clearfield 20 D lens. (Video courtesy of David Tremblay, MD)

 

 

Reviewed by George Magrath, MD, MBA

Charleston, SC-Recent iPhones can be used in place of traditional slit lamp cameras with image quality similar to conventional photographs.

“We started using the iPhone to be able to take pictures 24 hours a day, 7 days a week,” said George Magrath, MD, MBA, Storm Eye Institute, Medical University of South Carolina (MUSC), Charleston, SC. “[In the past] a lot of ocular pathology [might have] come in over the weekend or overnight [when] we were unable to use our slit lamp camera, because the department was closed, the technician wasn’t available, or we were in the emergency room. Being able to use a phone camera is a tremendous boost to clinical practice.”

A slit lamp camera, in trained hands, can produce clear, high-resolution images of the anterior segment. But such cameras can cost up to $10,000 and require the services of a trained slit lamp photographer to produce consistent, high-quality results.

An iPhone, in the hands of a resident or an emergency room physician, can also produce clear, high-resolution images of the anterior segment. The complete photographic set-up, including iPhone and slit lamp adapter, costs less than $350 and can be used with any slit lamp in any physical location.

Discovering the technology

What began as a work-around for first-year residents to send relevant patient images to their back-up or to on-call ophthalmologists is expanding. Emergency room physicians and providers have a need for immediate images for triage and treatment consults or to store for later teaching use.

The entire photographic system is little more than an iPhone, case, a clamp that holds the phone to the slit lamp ocular, and a base plate that stabilizes the phone on the fellow ocular in landscape mode.

The original adapter was based loosely on an Instructables.com presentation, but the adapter has many enhancements to provide the image quality needed for clinical use.

How iPhone captures images

Image capture uses standard iPhone controls.

In addition to simple, intuitive photographic controls and an excellent onboard image capture system, the iPhone offers built-in, high-dynamic range photography.

One setting captures three images in quick succession: one underexposed, one neutral, and one overexposed.  The software then produces a final image with improved dynamic range.

The iPhone also offers many lighting techniques. In addition to standard oblique, slit beam, and retro modes, the phone can be used with ambient room lighting to capture images quickly of gross pathology, such as corneal ulcers and defects in the eyelid.

Benefits to patients

Magrath

“Patients love the iPhone adapter,” Dr. Magrath said. “They see it as a good use of a technology they already know about, even if they don’t have a smartphone themselves.

“They like not having to move to another room for photography, which in our institution means walking up stairs,” he said. “They appreciate how quick and easy it is and that it is something that can be done then and there. . . . It makes for a less intimidating, less stressful exam. If you’re the physician, you known then and there that you have the images you want.”

However, using a camera phone to capture patient images could present privacy concerns, Dr. Magrath said.

MUSC physicians obtain informed consent and upload images directly into a patient’s electronic medical record, then delete the images from their phones to prevent transmission to a third party either intentionally or accidentally.

All iPhones at MUSC must be password-protected in case the phone is lost.

In other settings, the same system is used to send images to ophthalmologists on-call for advice on triage or immediate treatment.

“That ability to send photos to a remote expert and get immediate feedback is a powerful clinical tool,” Dr. Magrath said

Looking forward

The next step in his clinical research program is an unblinded study where lower-level residents send images to more senior residents for evaluation. Emergency room personnel would send images to the ophthalmology residents for evaluation and recommendations.

Telemedicine findings and recommendations could then be compared with in-person exams.

Another avenue for research is using blinded observers to evaluate image quality and clinical utility of iPhone images versus traditional slit lamp images.

There are also questions about the utility of images from other types of phones.

Dr. Magrath said he has only used the iPhone for slit lamp photography, but does not see any reason why a similar system would not work with an Android or other phone with equivalent image capture capabilities.

 

George Magrath, MD, MBA

P: 843/333-5241

E. magrath@musc.edu

Dr. Magrath has given instructions or constructed iPhone slit lamp adapters for physicians on request, but has no financial interest.

 

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