Posterior Segment Evaluation of Patients With SLE Using OCT and OCTA

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease that involves different organs and systems. The heterogeneous nature of the disease represents a great challenge in its diagnosis and management. Studies reported that the percentage of SLE patients demonstrating ocular manifestations can reach up to 30%. The pathogenesis of the ocular involvement is still unclear, but immune complex vasculopathy and inflammatory mediators might be implicated. The most common ocular manifestation in SLE was found to be kerato-conjunctivitis sicca(KCS) followed by retinopathy, where is the most severe manifestation was the optic nerve involvement, which might end up with irreversible blindness while anterior uveitis is a rare manifestation in SLE. Retinal involvement can vary from subclinical vascular changes to vaso- occlusive vision-threatening retinopathy. Lupus retinopathy is secondary to IgG complex-mediated micro-angiopathy that leads to small vessels infarcts. Currently, there is no agreement on existing biomarkers to identify SLE patients who have subclinical retinal involvement, or to identify whether micro-vascular changes in the retina are attributable to SLE. Lupus retinopathy is usually associated with high disease activity especially nephritis and cerebritis. On the other side, hydroxychloroquine,(HCQ) a cornerstone in lupus treatment, rarely causes ocular toxicity at doses of less than 6.5 mg/kg per day. Moreover, HCQ is found to be associated with retinopathy after a prolonged time of treatment (\>5 years). HCQ binds to melanin pigments in the retinal pigment epithelium (RPE). This binding may serve to concentrate the agents in the cell and contribute to their long-term effects. The classic pattern of retinal toxicity of HCQ is RPE depigmentation with foveal sparing, known as bull's-eye maculopathy. Although visual acuity in these patients seems intact, patients complain from para-central scotomas associated with reading difficulties. Besides, reduced color perception can be seen as retinopathy symptoms. That is why it is important to evaluate the eyes before starting therapy and during follow-up visits. Modern imaging techniques have provided easier and more accurate evaluation as Optical coherence tomography (OCT) is a noninvasive imaging technology, which picks up cross-sectional pictures of the retinal layers, detect thinning of retinal nerve fiber layer and macula. Optical coherence tomography angiography (OCTA) is a relatively new technique that allows visualization of the retina capillary bed and its subtle changes.