Objective: Dengue fever causes numerous systemic manifestations, including maculopathy, with loss of vision. This study sought to determine the prevalence of dengue maculopathy in patients hospitalized with dengue fever.
Design: Cross-sectional observational study in which consecutive patients hospitalized with dengue fever during a dengue epidemic were enrolled over a 3-week period.
Participants: Patients hospitalized in 2 general hospitals in Singapore with dengue fever.
Testing: Patients completed a standardized questionnaire and underwent tests for near and distance visual acuity (VA), Amsler grid testing, dilated retinal examination, serum complements C3 and C4, and urinary microalbumin.
Main outcome measures: Dengue maculopathy found on retinal examination.
Results: One hundred ninety-seven patients were enrolled, of whom 119 (60.4%) were male and 78 (39.6%) female. The patients ranged between 12 and 67 years old (mean, 32.65). One hundred sixty of 197 patients had positive dengue immunoglobulin M serology. Dengue maculopathy was detected in 27 eyes of 16 of the seropositive patients, giving a prevalence of 10% (95% confidence interval, 6.03%-15.40%). None of the patients who were dengue immunoglobulin M negative had dengue maculopathy. Dengue maculopathy eyes were more likely to have distance acuity worse than logarithm of the minimal angle of resolution 0.15 (Snellen 6/9 or worse) (P = 0.005) and abnormalities on Amsler grid testing (P = 0.001), with a greater proportion of these patients having visual complaints (P = 0.002) and lower mean complement C3 levels (P = 0.008) as compared with patients without maculopathy. Logistic regression analysis showed Amsler grid abnormalities to be the most consistent factor associated with dengue-related maculopathy (P<0.001), with a hazard ratio of 8.669; sensitivity, 29.6%; and specificity, 95.4%.
Conclusion: The prevalence of dengue maculopathy among patients hospitalized for dengue fever is 10% in our series. Amsler grid abnormalities, reduced distance VA, and the presence of visual symptoms are associated with dengue maculopathy. Low complement C3 levels in these patients suggest that this is an immune-mediated disease.