Heidelberg Spectralis Imaging System Guides Doctors
BILL KEKEVIAN, SENIOR ASSOCIATE EDITOR
The Heidelberg Spectralis is a multimodal imaging system. It provides several diagnostic images in a minimal amount of time, with less work than previous devices. For Karl Csaky, MD, of Texas Retina Associates in Dallas, it is changed his practice, especially how he communicates with patients. This tool provides more specific information than he could have obtained before. “We’ve seen patients react differently when we go over images from their exams,” he says. “A lot of patients have their children bringing them to the office. They want to know what’s happening to mom and dad. These images help them understand.”
As an SD-OCT that runs 100 times faster than the traditional time-domain OCT, the Spectralis acquires 40,000 A-scans per second. That speed and other digital capabilities mean the images the Spectralis produces have higher resolution and a clearer picture.
The features depend on the model. The top-of-the-line HRA+OCT model offers 12 modes: three OCT, six fundus-imaging, and three noncontact widefield modes.
“Typically, doctors perform SD-OCT scans to look for problems when a patient comes in with a complaint.” This has that OCT aspect, but Dr. Csaky adds, “I find that multimodality is the real value. In today’s practice, you might only need autofluorescein for 10% of patients, but when you do need it, it can dramatically impact your management of those patients.”
The FDA approved the Spectralis’ newest function, multicolor fundus imaging, in November. The function uses multiple laser colors simultaneously to selectively capture and display diagnostic information originating from different retinal structures. The increased detail can be useful to image patients with cataracts or nystagmus from whom it might otherwise be difficult to obtain images.
The imaging system’s TruTrack Active Eye Tracking follows the patient’s eye to reduce variables and produce a clearer, more precise image than was previously achievable.
“Very small eye movements can distort the image,” Dr. Csaky says. “TruTrack negates that, improving the signal-to-noise ratio. The main thing is image registration. It gives you precise locations in the eye and locks on them.” The photographer sets the parameters, ensuring point-to-point correlations between OCT and fundus images without postprocessing of the data.
Multicolor imaging is the newest Spectralis modality.
TruTrack works by simultaneously using two light beams. One captures an image of the retina and maps more than 1,000 points to track movement. The second is directed to the desired location despite blinks or movements.
Dr. Csaky has a particular fondness for the reference software, which compares two images over time. “Since both images are referenced it allows you to go line by line between the two images to compare them,” he says. Before this software existed, doctors had to estimate changes such as fluid accumulation. Although they’ve learned to read these images with great accuracy, Dr. Csaky says, “you could never really be sure.” The software aligns the image so the line scan is identical to the previous image. “Sometimes we’re talking about subtle changes. This is extremely sensitive software.”
GUIDING THE PHYSICIAN
The Spectralis won’t replace physicians, but it can now guide them more accurately. Dr. Csaky compares it to installing a GPS. “You may be used to driving without it, but when you need it, it really comes in handy. It means you can be sure where you’re going.” RP