MFERG Study of HCQ Retinopathy in Lupus Nephritis Patients: A Randomized Controlled Clinical Trial

The aim of the study to assess the multifocal ERG (mfERG) changes in SLE patients treated with chloroquine in renal patients with comparison to SLE patients without kidney affection.

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.1 Studies

reported that the percentage of SLE patients demonstrating ocular manifestations

can reach up to 30%.2

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.3

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.4 Lupus retinopathy is usually associated with

high disease activity especially nephritis and cerebritis. 5

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). 6 HCQ bind 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 paracentral 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. 7 To diagnose HCQ-induced retinopathy, various methods have been recommended, including: Spectral Domain Optical Coherence Tomography (SD-OCT), automated perimetry test, multifocal electroretinogram (mfERG), But it is controversial as to which of these methods is the Gold Standard early detection of HCQ-induced retinopathy. So it's important to find a tool that can help us diagnose early. 8 mfERG is highly sensitive among the mentioned tests and because it is an objective test, it is less dependent on the patient's response and cooperation .The mfERG objectively evaluates the electroretinographic response of the macular region, and in HCQ retinopathy, this response is reduced in the paracentral region

Eligibility Criteria:
Inclusion Criteria:

* 1. Age ≥18 years old. 2. Emmetropic patients with normal fundus. 3. Patients with SLE diagnosed by a rheumatologist with no ocular involvement upon clinical examination.

Exclusion Criteria:

- 1. Patients with history of intraocular surgery as cataract surgery ,retinal detachment surgery, anti-glucoma surgery.

2. Patients with significant media opacity as corneal opacity, cataract. 3. Patients with ocular diseases as glaucoma, uveitis. 4. Patients with systemic diseases as diabetes mellitus, hypertension.