The CMV retinitis becomes one of the most prevalent opportunistic infection in AIDS patients causing blindness. The prevalence of CMV retinitis in the cohort of 303 hospitalized AIDS patients was 7.6% in a single health center in Shanghai, China. It seemed that the occurrence of CMV retinitis in this retrospective study was lower than the prevalence reported in literatures[12
]. This prevalence may be over-estimated because the limitation of subjects in our study. But we could find the trend of CMV retinitis of patients in late stage of AIDS. In our understanding from a point of view of Chinese culture on their health and cost concern about doctor's visits, minor vision problem was and will not be the main reason for the AIDS patients to seek medical attention in comparison with other vital signs and symptoms at the later stage of disease course. Some patients only visited the doctor when their diseases were very serious. So many of them died from other infections or complications before CMV retinitis had been diagnosed. For example, seven advanced AIDS patients entered into the study died within 2 weeks after their primary admission to the hospital. Currently there is no well-organized epidemiological survey or study on the prevalence of CMV retinitis in the AIDS patients in China. So the prevalence of CMV retinitis in whole population of AIDS patients with different stages of disease in China still need to be identified. The results from the study indicated the prevalence of CMV retinitis of AIDS patients when they came to hospital for medical treatment. This study raises our awareness of special attention to full examination of the entire retina through a full dilated pupil using an indirect ophthalmoscope of AIDS patients in their first clinical visit since a majority of CMV retinitis could be asymptomatic and diagnosed only through clinical screening and ophthalmologic examination[8
]. The study also implies the importance and urgency to have national-wide epidemiology survey on the prevalence of CMV retinitis and to launch educational programs for AIDS patients to gain basic knowledge on retinitis and other potential opportunistic infection in their lifetime.
Seven patients died (11 eyes) and 16 patients (24 eyes) survived. The proportion of blindness and low vision in eyes infected with CMV retinitis respectively was 20.8% (5/24) and 29.2% (7/24) when they were diagnosed in survivors. The ganciclovir therapy was effective in 16 patients (24 eyes). After anti-CMV treatment, the proportion of blindness or low vision was 16.7% (4/24). The rate of blindness and low vision was high. CMV retinitis is a serious disease causing blindness, but the vision acuity of many patients will improve if anti-CMV therapy provided promptly. The vision acuity after anti-CMV in our study is the vision acuity while ending follow-up, so there was limitation. But these results of vision acuity showed the anti-CMV was effective.
Cotton wool patches are often observed in the early stage[13
]. It is important to keep in mind that it was often difficult to distinguish the cotton wool patches or hemorrhage along with retinal vessels in the early stage of CMV retinitis from the retinopathy induced by HIV infection. The white cotton wool patches identified in 3 eyes during the initial diagnosis had evolved into large area of yellow-white retinal lesions two months later without treatment of anti-CMV therapy. It becomes clear that early retinopathy can not be ignored and should follow-up closely in the ADIS patients.
According with previous studies[14
], our result showed that prevalence of CMV retinitis was closely related to the levels of CD4+
T lymphocyte counts in 303 AIDS patients in this cohort study. A routine ocular examination should be performed in the AIDS patients with CD4+
T lymphocyte counts less than 50 cells/μl. Taken together, the number of CD4+
T lymphocyte in peripheral blood is an empirical indicator on occurrence, progress, alleviation and regression of CMV retinitis in clinical diagnostic and management. In our study, CMV retinitis in 4 patients with CD4+
T lymphocyte counts > 50 cells/μl were diagnosed without ART. We should observe more cases to study the reason about CMV retinitis diagnosed in high CD4+
T lymphocyte counts patients such as race of people, age, complicating other disease et al.
CMV viral load was quantified with the real-time PCR assay to explore whether the level of CMV viral load in blood was correlated to the severity of CMV retinitis in this study. There was limitation to detect the level of CMV viral load in blood, sometimes CMV in the blood does not rule out the possibility of a different infection in the eye. It was reported that the CMV-PCR assay had a high predicting value with estimated sensitivity of 95% in detecting untreated CMV retinitis if vitreous samples were used[17
]. However, the vitreous sampling procedure has a risk to cause hemorrhage, infection and vision acuity loss, and was difficult to obtain patient's consent. So vitreous sampling is reserved for unusual cases with atypical features, where clinical findings are ambiguous and there needs to be clarification between other retinitis.
The choice of available drugs includes ganciclovir, foscarnet, cidofovir and fomivirsen. Because of cost and supply issues of anti-CMV drugs, ganciclovir is still the first-line anti-CMV drug for clinical management of CMV retinitis associated with AIDS in this study. In combination with antiretroviral medication, suppression of CMV disease for a short-term and maintenance of vision for a relatively long-term were achieved from this study. The CMV viral loads in patients after anti-CMV therapy were decreased below detectable level. Although it is reported that intravitreal injection of ganciclovir or intraocular implant of sustain-release ganciclovir improved treatment efficacy and reduce side-effect of the drug, this therapeutic procedure has neither been applied in the study nor reported in other central hospitals in China for treatment of CMV retinitis.
IRU is recognized as one of important causes of visions loss[18
]. Two cases of IRU (3 eyes) were diagnosed in our study (2/23). Their visions were 20/32, 20/40, 20/40, respectively, and average CD4+
T lymphocyte count was 112 cells/μl while vitritis and uveitis were observed. Goldberg reported that use of cidofovir increased the risk of IRU by a factor of 3.3[20
]. Although immune reaction to low level of CMV antigen in infected eye is essential to IRU pathogenesis, its mechanism is still not fully understood[18