OCT Angiography Parameters in Nasal Polyposis Associated with Chronic Rhinosinusitis

PURPOSE This study aimed to evaluate optical coherence tomography angiography (OCTA) parameters in cases of chronic rhinosinusitis with nasal polyposis (CRSwNP), a common cause of chronic airway obstruction. These parameters were compared with those of healthy individuals. METHODS In this prospective study, 29 eyes of 29 participants with CRSwNP and 30 eyes of 30 individuals in the healthy control group were evaluated. Cases diagnosed with CRSwNP were defined as group 1, and the control group as group 2. Nasal polyps were documented and graded using nasal endoscopy. A complete ophthalmic examination and OCTA analysis were performed. Retinal vascular density (VD) in four quadrants of both the superficial and deep capillary plexuses were analyzed. Foveal avascular zone (FAZ) area, retinal nerve fiber layer (RNFL), and vessel diameter index (VDI) were measured and compared. RESULTS Retinal VD in the superficial plexus showed a significant difference between Group 1 and Group 2 only in the nasal quadrant (p=0.046). In the deep capillary plexus, differences were statistically significant in all quadrants (nasal, temporal, superior, and inferior), with lower vascular density in the CRSwNP group (p=0.008, p=0.037, p=0.011, and p=0.001, respectively). In Group 1, FAZ areas were 0.390±0.81 mm ² and 0.395±0.96 mm ² in the superficial and deep plexuses, respectively. In Group 2, superficial and deep FAZ areas were 0.337±0.12 mm ² and 0.467±0.14 mm ² , respectively. The difference in FAZ area in the superficial plexus was not statistically significant, but the difference in the deep plexus was (p=0.062 and p=0.022, respectively). VDI was slightly higher in Group 1 than in Group 2, but the difference was not statistically significant in either the superficial or deep plexus (p=0.259 and p=0.200, respectively). The average macular RNFL thickness was 110.31±10.48 µm in Group1 and 93.22±11.50 µm in Group2, with the difference being statistically significant (p=0.007). CONCLUSION CRSwNP is an upper respiratory tract obstruction that can lead to hypoxia, increased small vessel resistance, dysregulation of nocturnal blood pressure, and alterations in perfusion pressure. The severity of nasal polyposis has been shown to significantly increase oxidative stress. CRSwNP may also result in differences in some OCTA parameters when compared to healthy individuals. To the best of our knowledge, this is the first study to evaluate OCTA findings in patients with CRSwNP. Our findings suggest that repeated hypoxic cycles may affect OCTA parameters, particularly in the outer retinal layers and the RNFL.