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SPOTLIGHT ON TECHNOLOGY & TECHNIQUE

An evolution in slit lamp fundus imaging

Smartphone adapters for slit lamps are understandably popular as they give ophthalmologists a precise and convenient way to capture external ocular images. But so-called smartphone funduscopy1 is less advanced. This technology cannot capture a wide-field view because the optics are limited by the bottleneck of the eye piece. Also, storing confidential patient information on a smartphone introduces numerous ethical and privacy issues.

One alternative to increasing the convenience of fundus photography is the recently FDA-approved Haag-Streit Fundus Module 300, which converts the Haag-Streit B-900 series slit lamp into a fundus camera.2

COMPACT DESIGN

By pivoting the slit lamp’s optical components to one side, the module can be attached. This motion allows the camera to swivel from the standby position into place and align with the cross slide. The slit lamp frame becomes the carrier for the camera. All other components of a standalone fundus camera are present, including the forehead and chin rests. This design limits the need for a separate imaging room and the need to transfer patients from one room to another.

“It is particularly useful in an emergency room setting and for the mobile office,” says Pascal Gartmann, director, Sales and Product Marketing, General Diagnostics Division of Haag-Streit,

The camera has a 40-degree field of view, nonmydriatic fundus image using a visible white light-emitting diode (LED). Nine internal fixation targets allow for midperipheral imaging up to 70 degrees horizontally and 52 degrees vertically. Its image sensor is a metal-oxide semiconductor with 5 megapixels; the image resolution is 1536 pixels x 1152 pixels.3 Once captured, the images upload to the diagnostic slit lamp imaging software program, EyeSuite, which is configurable with other third-party software programs.

Close-up view of the compact Haag-Streit Fundus Module 300.

USING THE DEVICE

Sami Hayek, MD, Lucerne Cantonal Hospital, University of Lucerne, Switzerland, says the camera is very easy to use. “Figuring out the best focus distance, when to use automatic or manual focus and how to avoid eyelash-related artifacts took only a few attempts.” He says he could get clear images of the central and mid-peripheral retina within a day.

It takes about 30 seconds to set up the camera, take the image and return the camera to the charging cradle. Calling the image quality “great” for routine documentation, Dr. Hayek says he has taken images of highly myopic fundus, retinal hemorrhages, nevi and the status of post-irradiation of a melanoma.

Pivot the slit lamp’s optical components to attach the camera.

COSTS AND CODES

The entire battery-operated module, including the cradle, costs about $10,000. Mr. Gartmann says using the fundus photography CPT code, with reimbursement of about $75 per image depending on the state, would cover the camera’s cost after 140 images.

Haag-Streit plans to increase the camera’s versatility, for example, improving EMR integration and incorporating software to create mosaic images from the midperipheral fixation targets. Also, like most white-light fundus cameras, a cataract’s dense media invokes light scatter, degrading image quality as compared to a scanning laser ophthalmoscope. That said, the camera is a compact and convenient imaging device. OM

REFERENCES

  1. Haddock LJ, Qian C. Smartphone technology for fundus photography. Retinal Physician. June 1, 2015. retinalphysician. http://tinyurl.com/lkr9qqu . Accessed May 11, 2017.
  2. Haag-Streit gains FDA approval for Fundus Module 300, ASCRS•ASOA 2017. prweb.com/releases/2017/04/prweb14284966.htm . Accessed May 2, 2017.
  3. Haag-Streit Fundus Module 300 Brochure. haagstreit.com/fileadmin/HaagStreit_Diagnostics/slitlamps/Imaging/Brochures_Flyers/Flyer_Fundus_Module_300_e_Web.pdf . May 11, 2017.