Retinal microvasculature alteration in patients with systemic sclerosis and chloroquine treatment

BACKGROUND: Retinal vascular abnormality is an important part of ocular systemic sclerosis (SSc), and long-term use of chloroquine can lead to retinal toxicity. This study was conducted to evaluate retinal microvascular changes using optical coherence tomography angiography (OCTA) in patients with SSc and SSc patients on long-term chloroquine treatment. METHODS: Fifteen SSc patients without chloroquine (30 eyes), 15 SSc patients taking long-term chloroquine (30 eyes) and 15 healthy controls (30 eyes) were recruited to this cross-sectional study. OCTA was used to examine the superficial and deep retinal capillary plexus in the macular retina of each eye. The densities of microvessels (MIR), macrovessels (MAR) and total microvessels (TMI) in the superficial and deep retina of the three groups were calculated and compared. We used the hemisphere segmentation method [superior right (SR), superior left (SL), inferior left (IL), and inferior right (IR)] and Early Treatment Diabetic Retinopathy Study (ETDRS) method [right (R), superior (S), left (L), and inferior (I)] to analyze changes in retinal microvascular density. RESULTS: The superficial and deep retinal MIR density in SSc patients decreased (P<0.05) compared with the healthy control group. This significant difference was found in both superficial and deep layers in S, L, SR, SL and IL regions (P<0.05), and additionally in the R and I regions in the superficial layer (P<0.05). Similarly, compared with SSc patients who did not take chloroquine, the superficial and deep retinal MIR density of SSc patients on long-term chloroquine also decreased (P<0.05). This significant difference was found in both superficial and deep layers in R, I and IL regions (P<0.05), and additionally in the IR region in the superficial layer (P<0.05). CONCLUSIONS: The OCTA results suggest that retinal MIR density is decreased in SSc patients, and that long-term use of chloroquine will aggravate this damage, resulting in a further decrease in retinal MIR density.