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Telemedicine screening for CMV retinitis using digital fundus photography provides an effective and efficient way to monitor at risk patients, reported Singapore researchers at the annual meeting of the American Academy of Ophthalmology. "With the advent of highly active antiretroviral therapy, CMV retinitis is now less common among patients with AIDS. However, there is an ongoing need for screening asymptomatic patients as this disease continues to blind many in underserved communities, and in developing countries. Preservation of vision depends on prompt detection and early treatment, noted Seo-Wei Leo MD, the Eye Institute, Tang Tock Seng Hospital , Singapore . Singapore has a national CMV retinitis screening programme for HIV patients in place, which forms part of its comprehensive public health response to the AIDS epidemic. The programme uses indirect ophthalmoscopy, the current gold standard for screening. However, this approach is costly and time-consuming, particularly at remote locations, she said.
For this reason, Dr Leo and colleagues designed a protocol to evaluate a telemedicine approach to the problem. Over a 12-month period, between April 2001 and March 20002, they performed 341 screenings of 682 eyes of 153 HIV patients. Patients were required to have at least one of the following symptoms: visual complaints; CD4 cell counts less than 50/microlitre; AIDS defining illness; or other CMV disease. The majority of patients in the study group, 86.5%, were males. Most, 83.9%, qualified for screening on the basis of low CD4 cell counts. Another 15.5% had manifest AIDS, while 5.3% had other CMV disease. Only 6.8% were screened on the basis of visual complaints. All of the patients underwent digital photographic screening using Zeiss FF450 fundus camera with a Kodak DCS620 digital back. A qualified ophthalmologist obtained nine standardised fields of 50 degrees each. These were captured and stored in tiff format, for subsequent panoramic reconstruction. Patients also underwent indirect ophthalmoscopy by another ophthalmologist who was blinded to the study protocol.
The digital images were interpreted on a 21-inch Sony Trinitron CRT. Patients had dilated pupils for all examinations. Ten of the images obtained by digital camera were unreadable. Of the 10 eyes concerned, seven had dense cataracts. Another two eyes were phthisical, and one eye had a vitreous haemorrhage secondary to proliferative diabetic retinopathy. This correlated with the indirect ophthalmoscopy findings, which graded all 10 cases as ‘poor view'. The digital screening was 100% sensitive, picking up all 17 eyes with CMV retinitis. In addition, the system had a specificity of 99.84%. One initially suspicious reading was later determined to be a false positive caused by an image artefact. Dr Leo noted that the study revealed an interesting difference in disease presentation compared to what might be expected in the Western world. While most CMV retinitis patients in the West present with visual symptoms, 71.4% of cases in this study were asymptomatic. Even among the 15.3% of patients who had visual symptoms, only a fraction were bothered enough by the symptoms that a consultation was considered necessary. This highlights the value of screening asymptomatic at-risk patients.
She explained that previously patients needed to spend considerable time and energy to receive routine screening for CMV retinitis. This telemedicine programme reduces the patients' need to travel. While once patients had to make repeated visits to different clinics and offices, they now only need to appear at one location for screening.This makes there lives easier and improves compliance with the programme, she said, adding: "By providing direct links between the patient and physician, telemedicine can bring medical expertise to a remote site. Our study illustrates how telemedicine can be used totransfer medical information for screening, diagnosis, and planning therapy." She added that the next step in the study would be to evaluate the use of trained medical technicians to read the images. CMV retinitis is still the most common cause of ocular morbidity in people with AIDS. In the early days of the epidemic it was an end-stage presentation, but with the development of aggressive anti-retroviral therapy HIV patients are living much longer. A major study published in 2003 (Kempen et al., Arch.Ophth, 2003; 121:466-476) concluded that a regimen of highly active anti-retroviral therapy greatly reduces the risk of vision loss among AIDS patients with CMV retinitis. Seo-Wei Leo MD
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