Investigation of structural changes of choroid in patients with recurrent aphthous stomatitis

Impairments in humoral and cellular immunity are observed in patients with recurrent aphthous stomatitis (RAS). The subfoveal choroidal thickness has been shown to increase in RAS patients. However, the number of studies monitoring structural changes of the choroid in these patients is limited. Therefore, in our study, the choroidal thickness (CT) and choroidal vascular index (CVI), determined by the ratio of vascular luminal area to choroidal area, were examined in RAS patients presented to or consulted in our clinic, and the variations in CT and CVI were compared with control cases, and the findings were associated with the presence of RAS. This cross-sectional study included 38 patients diagnosed with RAS in the dermatology clinic between July 2023 and November 2023, who were either referred to our clinic for consultation by the dermatology clinic or presented to our clinic for routine ophthalmologic examination. For the control group, 38 healthy individuals (without RAS), who were examined in our clinic during the same period, and whose age and gender distributions closely resembled those of the patient group, were selected. During the ophthalmological examination, intraocular pressure (IOP), spherical equivalent, visual acuity, axial length (AL), central corneal thickness (CCT), and keratometry (K1, K2) were measured. Using enhanced depth imaging-optical coherence tomography (EDI-OCT), retinal nerve fiber layer (RNFL), central foveal thickness (CFT), CT (central fovea, nasal, and temporal), and CVI data were measured, and the results were compared with healthy controls. The findings of the ophthalmological examination did not differ significantly between the two groups (P>0.05). The mean subfoveal CT of RAS patients increased significantly compared to healthy controls (P=0.046), but temporal and nasal CT values did not show a significant difference between the two groups (P>0.05). Additionally, the CVI values of RAS patients were significantly higher than those of healthy controls (P = 0.042). To the best of our knowledge, this study is the first to report a significant increase in CVI in patients with RAS, an inflammatory disease that usually occurs as the precursor symptom of Behçet's disease The inflammatory pathway in patients with RAS may increase ocular blood flow, leading to increased CT and CVI. Ocular changes detected in the examination of patients with RAS may be important for early diagnosis of Behçet's disease, as RAS may be a precursor of Behçet's disease. Our study may contribute to developing a deeper understanding of how choroidal components are involved in the pathogenesis of RAS using CVI