a 25-year - old female patient with good past health was admitted to a general hospital in hong kong with fever of unknown origin after traveling to indonesia . based on the clinical features and a positive real - time polymerase chain reaction for dengue virus type 1 the patient developed dengue macu - lopathy mainly affecting the vision of her left eye . as there is no proven treatment for dengue maculopathy , the patient opted for observation . dengue fever is an acute viral infection caused by four closely related dengue viruses ( flavivirus ) and transmitted through the bite of infected female aedes aegypti mosquitos . endemic areas are the americas , southeast asia , western pacific , africa and the eastern mediterranean . in hong kong , . the principal vector aedes aegypti is not found , but the prevailing species aedes albopictus can also spread the disease . dengue fever has become a notifiable disease to the hong kong department of health since march 1994 , and all reported cases are investigated to establish their source . clinical manifestations of dengue fever range from benign self - limiting fever , chills and headache to severe dengue haemorrhagic fever and dengue shock syndrome . diagnosis can be confirmed with laboratory tests such as the haemagglutination inhibition test , immunoglobulin g or m enzyme immunoassays and polymerase chain reaction ( pcr ) for dengue virus . common ocular manifestations include retinal haemorrhages , macular oedema , yellow spots , optic disc swelling and retinal vasculitis [ 5 , 6 , 7 ] . we report a case of bilateral dengue maculopathy with spontaneous recovery in a 25-year - old female patient . a 25-year - old female with good past health presented to a general hospital in hong kong with a 2-day history of fever , headache and retro - orbital pain preceded by papular rash over both hands and both feet . systemic workup revealed lymphopenia , neutropenia , thrombocytopenia and a negative culture for sputum , blood and stool , and the patient was negative for anti - hiv antibodies , malaria , leptospira and rickettsial antibodies . real - time pcr for dengue virus type 1 was positive so that the diagnosis of dengue fever was confirmed . four days after admission , the patient complained of a paracentral absolute scotoma in her left eye . on examination , the snellen visual acuity in her right and left eye was 20/25 and 20/60 , respectively . there was no relative afferent pupillary defect or loss of colour perception on ishihara test plates . amsler chart testing showed a round , absolute scotoma inferotemporal to the fixation point in her left eye . fundal examination showed an area of retinal infiltrate and a haemorrhage superonasal to the fovea in her left eye and some retinal pigment epithelium ( rpe ) changes in her right eye ( fig . spectral - domain optical coherence tomography ( oct ) was performed and showed retinal thickening corresponding to the area of retinitis and haemorrhage . 2 ) . multifocal electroretinogram ( erg ) showed a reduction in first - order kernel responses at the central maculae of both eyes ( more severe in the left eye ) ( fig . secondary to dengue fever and the absence of a proven benefit of steroid treatment , the patient opted for observation . one week after the onset of visual symptoms , the vision of her left eye deteriorated to 20/250 . aqueous tapping with an aseptic technique was performed and sent for pcr for cytomegalovirus , herpes simplex and varicella zoster viruses . the patient opted for empirical treatment with oral valganciclovir 900 mg bid for a few days until the results of the pcr were negative . eleven days after visual symptom onset , the patient 's condition started to improve with less retinal haemorrhage and resolving retinitis . after 9 months , her snellen best - corrected visual acuity was stable at 20/20 , but there were a persistent reduction in retinal responses on multifocal erg and a persistent paracentral scotoma . the prevalence of maculopa - thy in patients hospitalized for dengue fever was reported to be 10%   and there was no case of dengue maculopathy during the dengue epidemic in 2007 . ocular involvement is usually asymmetric , with a best - corrected visual acuity ranging from 20/30 to hand movements , and it usually occurs 67 days after the onset of dengue fever symptoms [ 5 , 6 , 7 ] . the patient recovered from dengue fever within about 1 week , and her ocular symptoms lasted for about 3 weeks . there was no report on the relationship between the course of recovery of the systemic condition and that of maculopathy . multifocal erg was shown to be a useful tool , especially in cases with absent or subtle clinical signs . the area of reduction in first - order kernel responses corresponds well to the scotoma and represents the dysfunction of photoreceptors . in our case , the multifocal erg demonstrated the reduction in retinal responses in the asymptomatic eye , implying bilateral involvement . such localized retinal dysfunction may persist despite improvement of visual acuity . in a study by chia et al . , there was little change or incomplete resolution in 9 out of 15 patients over 3 to 10 months . visual recovery may be prolonged or scotomata may persist even at 2 years [ 10 , 13 ] . in our case , although visual acuity recovered spontaneously , there were persistent changes on multifocal erg . there were three patterns of maculopa - thy : diffuse retinal thickening , cystoid macular oedema and foveolitis . scotomata were shown to persist longest in patients with foveolitis and shortest in those with diffuse retinal thickening . there is no proven antiviral treatment or commercially available vaccine for both dengue fever and dengue maculopathy . it is postulated that there may be an immune basis for the occurrence of maculopathy rather than a direct viral infection . low serum complement 3 levels had been found to be significantly associated with the presence of dengue macu - lopahty . the 6- to 7-day delay in the onset of visual symptoms from the acute viral infection corresponds to the time of onset of antibody production or immune complex deposition . direct viral infection causes apoptosis and dysfunction of endothelial cells , dendritic cells , monocytes and hepatocytes . this may lead to an aberrant immune response causing overproduction of cytokines and subsequent production of autoantibodies against platelets and endothelial cells . it is uncertain whether dengue maculopathy is associated with the production of autoantibodies against retina , rpe or choroidal antigens [ 14 , 15 ] . there was a case of dengue maculopathy , who recovered rapidly from counting fingers to 20/40 while on high - dose oral prednisolone , but experienced a visual deterioration to counting fingers as the steroid was tapered . this patient was lost to follow - up and the final outcome was not known . in a retrospective study of dengue foveolitis , 5 of 6 patients were treated with periocular steroids , oral prednisolone , intravenous methylpred - nisolone or intravenous immunoglobulin . all but one eye had a best - corrected visual acuity of 6/7.5 or better at a mean of 2.2 months . however , the good visual outcome may also be the natural course of the disease . in conclusion , immunity to one serotype of the dengue virus would not confer protection against subsequent infection with the other three serotypes . education on preventive measures such as avoiding mosquito bites and eliminating stagnant water is also important .
purposeto report a case of dengue maculopathy , which resolved spontaneously without treatment.methodsa 25-year - old female patient with good past health was admitted to a general hospital in hong kong with fever of unknown origin after traveling to indonesia . 
 based on the clinical features and a positive real - time polymerase chain reaction for dengue virus type 1 , she was diagnosed with dengue fever . 
 the patient developed dengue macu - lopathy mainly affecting the vision of her left eye . 
 abnormalities on a multifocal electro - retinogram showed bilateral involvement.resultsas there is no proven treatment for dengue maculopathy , the patient opted for observation . 
 her vision returned to normal within 3 weeks.conclusiondengue maculopathy can cause severe visual loss and may resolve without treatment .