Ophthalmic manifestations in seropositive dengue fever patients during epidemics caused by predominantly different dengue serotypes

Purpose: Dengue fever (DF) epidemics in Singapore in 2005-2006 and 2007 were caused predominantly by dengue virus serotypes 1 (DENV-1) and 2 (DENV-2) respectively. We investigated the prevalence of ophthalmic manifestations during these consecutive epidemics. Methods: Seropositive DF patients admitted to the hospital during two separate dengue epidemics were enrolled from June 2005 to December 2007. Demographic, ophthalmic, and laboratory data were collected. The primary outcome measures were differences in ophthalmic and laboratory features across the two epidemics. Factors associated with increased risk of developing various DF-related ophthalmic manifestations were the secondary outcome measures. Results: Of the 115 patients enrolled, 109 (94.7%; 33 in 2005-2006 and 76 in 2007) completed the eye screening protocol. Majority of patients were Chinese (65, 59.6%) and males (81, 74.3%). The mean age was 40.8 years (range, 18-87). Colour vision impairment (12 vs 14 [36.4% vs 18.7%]; P = 0.04), cotton wool spots (10 vs 3 [30.3% vs 3.9%]; P < 0.001), bleeding diathesis (7 vs 3 [21.2% vs 3.9%]; P = 0.004) and abnormal liver function (mean alanine amino-transferase [150.2 U/L vs 68.28 U/L; P = 0.001], mean aspartate amino-transferase [196.86 U/L vs 99.53 U/L; P = 0.002], total protein [68.43 g/L vs 72.27 g/L; P = 0.016], serum albumin [36.86 g/L vs 40.5 g/L; P = 0.001]) were noted more often in DF epidemics predominantly caused by DENV-1 compared to DENV-2. Conclusions: A higher prevalence of colour vision impairment, cotton wool spots, bleeding diathesis, and abnormal liver function was found in DF epidemics predominantly caused by DENV-1 compared to DENV-2.