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Undilated retinal viewing possible with new system
PITTSBURGH — A full retinal view without pupillary dilation now appears to be possible. An imaging device obtains images approaching the quality of 35-mm slide photography with good coverage into peripheral retina, according to researchers. The system may be effective for retinal screening exams, especially in primary eye care.
Two studies of the Optos Panoramic200 non-mydriatic scanning laser ophthalmoscope, which makes the Optomap retinal exam possible, show that it produces high resolution color digital fundus images with anatomical and pathological detail comparable to an examiner viewing the retina with an indirect ophthalmoscope, according to the manufacturers, Optos PLC, a Scottish company.
The system, which was approved by the Food and Drug Administration in 1999, is the “world’s first system capable of producing a single, high-resolution, ultra-wide field color digital image of the retina without the need for pupil dilation,” said company spokeswoman Karen Miller, with Optos North America, based in Massachusetts.
The device employs a red-green scanning laser and takes less than 2 minutes to complete imaging, Ms. Miller said.
High sensitivity
The preliminary results of a University of Pittsburgh study demonstrated an average sensitivity of 85% among three retinal specialists when comparing findings from the Optomap images and indirect ophthalmoscopy. Average sensitivity was defined as the total number of true positive findings divided by true positives plus false negatives.
There were no false positive findings for the Optomap images, and 41 of 43 scans were acceptable for physician reading.
Forty-four patients with known diabetes and 22 healthy patients were included in the study, which has not been concluded and will eventually evaluate additional patients.
The double-masked study demonstrated that the Optomap exam may be effective in screening for diabetic retinopathy and other retinal disorders, said principal investigator Thomas Friberg, MD, director of retinal services at the Eye and Ear Institute, University of Pittsburgh.
Dr. Friberg said he was unable to make conclusive statements about the exact clinical usefulness of the imaging system while the study in his center is ongoing, but he did offer initial impressions with respect to its performance.
Dr. Friberg said the Optomap exam is the first truly non-mydriatic imaging system he has used. Other types of cameras that have claimed to be non-mydriatic have often failed to perform on undilated eyes, he said.
“With some of those machines you end up having to dilate the patient anyway. With this system, we have a lot fewer failures with respect to being able to take an image through their undilated pupil. It’s unusual if we can’t image them. If they have a dense media opacity, that’s a different story, but generally we can image them,” Dr. Friberg said.
“For a noncontact machine that goes far out into the periphery, I think this has significant potential,” he said.
The resolution of the image is good, Dr. Friberg said. Ease of performing the scan, patient acceptance and use of the images to help in patient education are also favorable aspects of the Optos system, he said.
Primary eye care
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“There are a lot of patients who don’t like to be dilated. In a primary eye care setting there are some that just downright refuse to be dilated, and this gives you another way of evaluating the retina without dilating the patient. Compared to direct ophthalmoscopy it does a fabulous job. Compared to a dilated exam it is almost equal,” Dr. D’Auria said.
Dr. D’Auria and colleagues participated in a study that evaluated the sensitivity of the device, compared with a manual clinical exam, in detecting pathology in 300 eyes of 150 patients. Among three practitioners the reported sensitivity of their manual exam was 79%, 56% and 42%. The sensitivity of the doctors using Optomap images only to detect retinal pathology was 74%.
As skill levels differ between practitioners, there will be variations in clinical findings, Dr. D’Auria said.
“Those with more skill tend to find things not readily apparent in the Optomap image, such as lattice degeneration, some things out in the periphery, but you can also find that with the Optomap exam. Some practitioners are just better skilled at doing certain tests than others,” she said.
Dr. D’Auria said she finds after 2 years’ experience with the imaging system that “this a great tool in the primary eye care setting. I was very pleased with it.”
Patient-friendly
“Right now the people who have it in their practices are basically charging the patient to have it done,” Dr. D’Auria said. “It depends on where you are and what the patient can afford, but a lot of patients would definitely pay $20 to avoid dilation. A lot of people, if they have to get to work, refuse to be dilated.”
The system has not been assigned a reimbursement code at this time, although use of the photography billing code is acceptable if pathology is present in the image, Ms. Miller of Optos said.
The Optos Panoramic200 system is available through the company’s Access Technology Now program; there are no lease costs or other initial capital outlays required. A nominal per-patient fee is collected by the company.
For Your Information:
- Karen Miller can be reached at Optos North America; (800) 854-3039; fax: (508) 486-9310; e-mail: kmiller@optos.com.
- Thomas Friberg, MD, can be reached at the Eye and Ear Institute, 203 Lothrop St., #824, Pittburgh, PA 15213; (412) 647-2214; fax: (412) 647-5119; e-mail: friberg@vision.eei.upmc.edu. Dr. Friberg has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Cynthia D’Auria, OD, can be reached at New England Eye Center, 750 Washington St. Boston, MA 02111; (617) 636-4600; (617) 636-4867; e-mail: cd’auria@lifespan.org. Dr. D’Auria has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.
- For information on the Panoramic200 contact Optos North America; (800) 854-3039; fax: (508) 486-9310.