Occlusive retinal vasculitis in an immunocompetent woman: rare presentation of ocular melioidosis

Burkholderia pseudomallei is a known great mimicker responsible for melioidosis. Ocular involvement in melioidosis is unusual, with eyelid and orbital infection as the commonest presentation. We describe a 41-year-old, healthy woman who complained of reduced vision in her left eye. On examination, vision in the left eye was 6/9. There was evidence of occlusive retinal vasculitis on fundoscopy examination. Fundus fluorescein angiogram showed extensive capillary fallout. Diagnosis was established by a rise in the serum antibody titre for the bacterium and further supported by clinical improvement of vision after completion of treatment antibiotics. Sectoral panretinal photocoagulation at the capillary fallout area successfully arrested the sequelae of retinal ischaemia. Occlusive retinal vasculitis is a rare presentation of melioidosis. Early prompt diagnosis in an immunocompetent individual helps prevent visual-related morbidity. The ability of this bacteria to cause recurrent infection in an endemic area should not be underestimated.

Retinal vascular bed area on ultra-wide field fluorescein angiography indicates the severity of diabetic retinopathy

AimsTo quantify retinal vascular bed area (RVBA) in square millimetres on stereographically projected ultra-wide field (UWF) fluorescein angiography (FA) in eyes with diabetic retinopathy (DR).MethodsA prospective, observational study. Baseline Optos 200Tx UWF FA images of 80 eyes with DR from the DAVE (NCT01552408) and RECOVERY (NCT02863354) studies were stereographically projected at the Doheny Image Reading Center to adjust for peripheral distortion. The early-phase FA frame was used to extract the retinal vasculature as a mask for calculating RVBA. The pixels of the retinal vasculature were automatically computed in square millimetres using manufacturer-provided software.ResultsEighteen of 80 diabetic eyes were excluded because image quality and contrast were insufficient for automatic extraction of the retinal vasculature from the background fluorescence. The remaining 62 eyes were included in the final analysis. In comparison with age-matched and sex-matched normal controls, eyes with DR had a higher global RVBA for the entire retina (p<0.001), and RVBA correlated with DR severity (p<0.001), with a higher RVBA in eyes with proliferative DR (66.1±16.2 mm2) than in those with non-proliferative DR (56.2±16.6 mm2) or in normal controls (37.2±9.9 mm2). This tendency was also present in the posterior retina and mid-periphery but absent in the far-periphery. RVBA did not correlate with retinal ischaemia (p>0.05).ConclusionsEyes with DR harboured a larger global RVBA for the entire retina than normal controls, and RVBA appeared to indicate DR severity. However, this biomarker was not observed to be a good indicator of retinal ischaemia.

Diabetes and the eye

Diabetes mellitus is still one of the commonest causes of blindness worldwide. The ophthalmic complications of diabetes include diabetic retinopathy (DR), cataracts, primary open angle and neovascular glaucoma, and cranial nerve palsies. Retinovascular disease, including retinal vein and artery occlusion, and non-arteritic ischaemic optic neuropathy are more common in diabetic subjects. DR occurs in approximately 30–35% of diabetic subjects with ethnic differences. The primary abnormalities of DR are capillary basement membrane thickening, such that it becomes porous, and capillary occlusion with resultant retinal ischaemia. In Type 1 diabetes, DR is almost invariable after 15 years of disease duration. In Type 2 diabetes, 20% have retinal signs at diagnosis of diabetes, rising to a prevalence of 60% after 15 years of known disease duration. Major modifiable risk factors for DR include poor glucose and blood pressure control, and increasing lipid levels. In broad terms, Type 1 diabetes is associated with proliferative retinopathy, and Type 2 diabetes with maculopathy.

Pre-proliferative and proliferative retinopathy

Pre-proliferative retinopathy precedes proliferative retinopathy (new vessel growth) and, therefore, is an indication that the eye will soon be leading on to the advanced stages of retinopathy. Pre-proliferative retinopathy indicates chronic retinal ischaemia due to blocked capillaries. The clinical signs include multiple deep round blot haemorrhages, intra-retinal microvascular abnormalities (IRMA), and venous beading/or venous reduplication. New vessels arise at the optic disc (NVD) or new vessels elsewhere (NVE) on the retinal surface due to retinal ischaemia and increase vascular endothelial growth factor (VEGF), and others. The new vessels help compensate the hypoxic (oxygen-starved) tissue. These new vessels can easily rupture leading to haemorrhage (vitreous haemorrhage) and severe visual loss.