Abstract
Purpose :
Both plaquenil toxicity (PT) and ocular manifestations of Systemic Lupus Erythematosus (SLE) are known to lead to central visual field defects and thinning of the retina. However, the retinal layers that are initially affected may differ between the two. Plaquenil adsorbs to melanin within the RPE in a bulls-eye pattern around the macula, while SLE may cause inflammation and ischemia within the inner retina. In patients with SLE, optical coherence tomography (OCT) and OCT angiography (OCTA) may provide a method of differentiating the two by isolating the inner and outer retinal thicknesses and quantifying ischemic areas within the macula.
Methods :
A retrospective, cross-sectional study of 43 patients, 16 with SLE, 17 with non-SLE autoimmune diseases, and 10 age-matched controls were scanned using a CIRRUS™ 5000 with AngioPlex® OCT Angiography (ZEISS, Dublin, CA). 512x128 macular cube scans and 3mm x 3mm angiography scans were obtained on each patient. A multi-layer segmentation was applied to cube scans to separate the inner and outer retinal layers at the outer margin of the inner nuclear layer (Fig. 1). The average vessel density (VD) was calculated within the inner ring of an ETDRS grid using multiple retinal slab segmentations. Patients were grouped based on clinically diagnosed disease state as well as presentation of PT. Groups were compared using a student’s t-test with significant deviation defined as p<0.05.
Results :
Figure 2 details p-value comparisons between groups. SLE patients with PT (116.1 ± 28.2) exhibited a thinner inner retina than other groups, while the inner retinal thickness of non-SLE patients with PT (156.1 ± 7.4) and controls (152.1 ± 6.7) did not differ. Outer retinal thickness was thinner in patients with PT (135.1 ± 9.9) than controls (157.5 ± 12.9). VD was also decreased in both PT patient groups in the deep capillary plexus in comparison to their respective non-PT cohorts and controls.
Conclusions :
PT may cause specific thinning within the outer retina, while lupus-related maculopathy affects primarily the inner retina. This may indicate that mutli-layer segmentation analysis can be more useful than full thickness analytics in differentiating the two. Additionally, PT was shown to generally decrease retinal VD in both groups.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.