Lyme neuroretinitis in Singapore: a diagnostic dilemma.

three-disc-diameters with a pale, swollen optic disc (Fig. 1A). Colour vision, using the Ishihara’s screening test for colour defi ciency, was normal in the right eye but left eye testing could not be performed. A HumphreyTM visual fi eld test showed a diffuse dampening of the left visual fi eld. Based on these fi ndings, a provisional diagnosis of left non-arteritic anterior ischaemic optic neuropathy (NAAION) was made. Blood investigations revealed normal full blood count, erythrocyte sedimentation rate, renal panel, glucose and glycated haemoglobin levels. The Venereal Disease Research Laboratory (VDRL) and fl uorescent treponemal antibody absorbed (FTA-ABS) tests were negative. Autoimmune antibodies, such as anti-nuclear antibody, anti-double-stranded DNA antibody and anti-phospholipid antibody, were negative. One week later, there was no improvement in vision in the left eye. However, the macular oedema appeared to be resolving and the disc was pale. Magnetic resonance imaging (MRI) of the brain and anterior visual pathways was then performed, which were normal. A macular star started to appear at 3 weeks from onset of symptoms with persistence of a pale disc with blurred disc margins (Fig. 1B). A diagnosis of left neuroretinitis was made and a work-up for possible infective causes was done. The patient was then reviewed a week later and visual acuity in the affected eye had shown some improvement to CF at 3 metres. Visual fi eld testing by confrontation revealed a central scotoma and a left RAPD was still present. Patient was then started on oral prednisolone 30 mg once-a-day in view of possible infl ammatory aetiology for the neuroretinitis. Immunoglobulin G (Ig G) titres for Dear Editor, Neuroretinitis is an infl ammatory process of the optic nerve, typically characterised by optic disc oedema and the presence of a macular star.1, 2 The aetiology is usually infectious3 and neuroretinitis secondary to Lyme disease is a rare occurrence worldwide.4 To date, there has been no reported incidence of Lyme disease in Singapore. We report an interesting case of neuroretinitis with falsepositive enzyme-linked immunosorbent assay (ELISA) serology for Lyme disease in Singapore. As a result, the patient was treated with antibiotics with some symptomatic relief. Subsequently, a repeat ELISA Lyme’s test done did not show a rising titre and Western blot test for Lyme disease was negative. It is hence crucial to establish a correct diagnosis for Lyme neuroretinitis for appropriate treatment.