Discussion

Dengue fever, the most common mosquitoborne viral disease in humans, is a multisystemic disease with known complications⁽¹⁾, which includes blurring of vision, scotoma, ocular pain, metamorphopsia, micropsia, impairment of color vision and floaters. It usually occurs within the first month after contracting dengue fever. The main ocular findings have been found in both anterior and posterior segments which include subconjunctival hemorrhages, anterior uveitis, vitritis, macular and retina hemorrhage, diffused retina edema, Roth’s spot, macular yellow spots, and optic disc swelling⁽¹⁾. FFA showed leakage in the optic disc and retinal vessels, macular nonperfusion, and RPE defects, suggesting that the retina and RPE were the primary sites of involvement. The pathophysiological mechanism behind dengue infection and ocular involvement is still unclear, but is speculated to be related to an immune-mediated process^(2,3). The aggressive immune response may cause increased capillary permeability, plasma leakage, and hemorrhagic diathesis. This hemorrhage bleeding tendency can occur in both the retina and choroid causing retina hemorrhage and choroidal circulatory disorders. The outer retina layer is fed by choroidal circulation making it vulnerable to ischemic diseases.

In this study, both patients tested positive for dengue serology. It was noted that similar symptoms and retina changes occurred in both cases, which could be explained by the immune theory. The white spots were found in the retinal outer layers and only around the retinal capillaries. According to the immune-mediated process^(2,3), the pathophysiological mechanism of these white spots may be explained by antigen-antibody complex deposit around venular and arteriolar because of the increased capillary permeability.

Both patients’ initial symptoms were also characteristic of multiple evanescent white dot syndrome (MEWDS): multiple yellow-white spots at the level of multiple layers of the retina, RPE, choriocapillaris, and the choroid. Jampol et al.⁽⁴⁾suggested that MEWDS was a specific type of autoimmune disease, which was usually a self-limiting condition with patients recovering and achieving a good visual acuity within several weeks. Choroidal circulation disturbance may also be involved. Therefore, it is doubtful that both disease have similar or same immune-mediated process.