FOCUS ON THE FUNDUS
TWO-IN-ONE SYSTEM PROVIDES PRECISE RETINAL INFORMATION
MURRAY FINGERET, O.D., F.A.A.O.
THE FUNDUS automated perimetry (FAP) COMPASS imaging system, by CenterVue, captures threshold visual field images and fundus photos.
The device is made up of an automated perimeter and a scanning ophthalmoscope. Specifically, the device provides true-color, confocal images of the retina and measurements of retinal threshold sensitivity under non-mydriatic conditions. The resulting image has a 60° field of view with a 30° projection field.
At the beginning of the test, the device takes an infrared picture of the back of the eye, acting as an auto-refractor, to measure the eye’s refractive power.
The resulting image is transmitted to a tablet device, and a circle is overlaid on the picture. With my finger, I move the circle over the photo of the optic disc to plot the blind spot. Then, I select which test to conduct (24-2 or 10-2), and the system lays out the pattern points. (This set up eliminates fixation problems from the equation, although false positives and negatives are still significant.)
Next, the device utilizes real-time retinal tracking at 25 images per second. If the patient moves, the instrument adjusts and accounts for the movement before projecting the stimulus that the patient detects. The real-time retinal tracking system occurs throughout the test. The tracking path and the time remaining to complete the test are displayed. The test takes about five minutes, which can vary slightly depending on whether you have selected 24-2 OR 10-2, and includes the taking of the photograph.
COMPASS image. The patient has both glaucoma and an epiretinal membrane.
The FAP COMPASS generates a print out showing the test location results in decibels on the actual fundus picture (vs. a flipped image), gray scale, the pattern deviation plots and a fixation analysis. Additionally, the device compares the visual field result against the age-appropriate normative database.
COMPASS is fully automated and has an operator-friendly interface, requiring nominal training. The test is easy to run, making images simple to acquire. Make sure that the patient is comfortable at the instrument for optimal results.
Real-time visualization improves the overall experience. This function allows the technician or O.D. to see whether the person is getting tired or whether the eye is drooping, causing edge points to be missed.
Additionally, the test may be suspended at any point without loss of data, which helps ensure patient comfort.
By combining the forces of an automated perimeter and a scanning ophthalmoscope, the FAP COMPASS allows me to put structure and function results together in one test, which streamlines the diagnosis and management process for my patient and my practice. OM
DR. FINGERET is chief of the optometry section, Brooklyn/St. Albans Campus, Department of Veterans Administration New York Harbor Health Care System and a clinical professor at the State University of New York, College of Optometry and a fellow of the American Academy of Optometry. He founded the Optometric Glaucoma Society and regularly speaks and lectures on the topic. Visit tinyurl.com/OMcomment to comment.