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Telemedical evaluation appears accurate in diagnosing ROP
With a decreasing number of physicians screening for the disease, the technology could become crucial for premature infants.
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Intra-physician agreement between ophthalmoscopic and telemedicine-based diagnosis of retinopathy of prematurity is high, according to study results.
“There’s a problem with the current state of care,” Michael F. Chiang, MD, told Ocular Surgery News in a telephone interview. “We’ve got more and more premature babies who are surviving, yet fewer ophthalmologists to screen for retinopathy of prematurity (ROP).”
Fewer physicians are willing to screen for ROP because the examination is time-consuming and difficult, Dr. Chiang said, adding that telemedicine could potentially solve these problems.
In a prospective study presented at the American Academy of Ophthalmology annual meeting in New Orleans, he and colleagues investigated the agreement between ophthalmoscopic examination and image-based telemedical analysis in the diagnosis of ROP in 67 consecutive premature infants hospitalized at the Columbia University neonatal intensive care unit (NICU) between November 2005 and October 2006.
“Of all the babies that we examined for ROP over the course of a 1-year study recruitment period, we consented about 62% for this study. I think that it’s a good sample of what we’re doing in the real world,” Dr. Chiang said.
The study
One of two physicians performed both evaluations for each patient: the dilated ophthalmoscopic examination between 31 and 33 weeks or 35 and 37 weeks postmenstrual infant age and the telemedical examination. In both evaluations, patients were diagnosed with no ROP, mild ROP, type 2 pre-threshold ROP or treatment-requiring ROP.
The telemedical examination was conducted using posterior, temporal and nasal images taken with a wide-angle fundus camera (RetCamII, Clarity Medical Systems) by a trained NICU nurse.
“Our protocol had them capture up to two additional images if, in the opinion of the nurse, they added some diagnostic value,” Dr. Chiang said.
The images were taken during two sessions and uploaded to a Web-based system developed by the study authors. Along with the photographs, the nurses uploaded clinical data, including basic patient demographics, birth weight, gestational age and postmenstrual age. After 4 to 12 months, telemedical interpretations were performed by the same ophthalmologist who performed the original ophthalmoscopic examination, and results were compared.
Diagnosis agreement, discrepancy
For the 134 total eyes, the researchers found absolute agreement between the two examinations in 86.3% of cases and discrepancies in 13.6% of cases.
Most clinically significant discrepancies involved zone 1 ROP. Specifically, zone 1 disease was diagnosed in two eyes by ophthalmoscopy but not telemedicine and in six eyes by telemedicine but not ophthalmoscopy, Dr. Chiang said.
“Based on guidelines from the Early Treatment for ROP (ETROP) randomized controlled trial, if you have stage 3 disease in zone 1, you have treatment-requiring disease, and if you have stage 1 or 2 disease in zone 1 … then you have what’s called type 2 ROP, which has significant implications in terms of follow-up and risk for progression,” he said.
Zone 1 ROP is diagnosed by doubling the distance between the optic disc and macula. That distance becomes the radius of a circle, and any peripheral ROP in that circle is diagnosed as being in zone 1. This analysis, in particular, may be easier to conduct with a photograph obtained through telemedicine than with a wiggling, fragile infant, Dr. Chiang said.
“I think that there’s definitely some rationale that if you’ve got the photograph, it might be more precise and reproducible than ophthalmoscopy,” he said.
Dr. Chiang and colleagues also saw discrepancies involving plus disease, which was diagnosed in two eyes by ophthalmoscopy but not telemedicine and in two eyes by telemedicine but not ophthalmoscopy. Plus disease is diagnosed by comparing a patient’s venule dilation and arteriole tortuosity to that of a standard published photograph.
“If you have plus disease, it means that the baby needs to be treated with laser. … Plus disease is a crucial parameter to diagnose properly,” he said.
Working system
“What we’re really talking about is using technology to expand the availability of patient access to experts who can diagnose disease, but you’ve got to get the picture to the expert,” Dr. Chiang said.
With formidable data showing the accuracy of telemedicine screening, the next step involves dealing with workflow issues. To put a telemedicine screening program in place, an accepted protocol for the photographers and protocols for reading the images would be required, he said.
Additionally, a working system would need to ensure that retinal images are taken, uploaded onto the system, interpreted by an expert and returned to the NICU in a short period of time. “Timely for this disease means that if you’ve diagnosed treatment-requiring disease, you need to treat it within 48 to 72 hours,” Dr. Chiang said.
The time factor is one reason why the best person to photograph the eyes is the neonatal nurse, who is already present in the NICU and knows how to deal with premature infants, he said.
“It would defeat the purpose to have an ophthalmologist be the person who takes the picture because if they’re there, they might as well examine the baby,” Dr. Chiang said.
Decreasing screening rates
Telemedicine screening for ROP may become more important in the future, especially as ophthalmoscopy screening rates decrease, Dr. Chiang said.
Survey data have shown that there are fewer and fewer ophthalmologists who are willing to perform these ROP ophthalmoscopic exams, he said. “That’s because of a lot of concerns about the time that it takes to do them because you’ve got to coordinate all these exams, walk or drive to the neonatal intensive care unit and go from bed to bed examining each infant. It’s a completely different model from what ophthalmologists are used to.”
Premature infants are difficult to examine for ROP, especially for someone not trained to deal with them. They are fragile, often sick and wiggle around during examination, Dr. Chiang said.
“One thing that we know is that there often aren’t enough pediatric ophthalmologists and retinal specialists available to do these examinations and treatments,” he said.
For more information:
- Michael F. Chiang, MD, can be reached at Columbia University College of Physicians and Surgeons, 635 W. 165th St., Box 92, New York, NY 10032; 212-342-3440; fax: 212-305-5962; e-mail: chiang@dbmi.columbia.edu. Dr. Chiang is an unpaid member of the scientific advisory board for Clarity Medical Systems.
- Jessica Loughery is an OSN Staff Writer who covers all aspects of ophthalmology.