Observational Study of Dark without Pressure in Myopic People Based on Ultra-widefield SS-OCTA and Ultra-widefield CFP

Purpose: This study aimed to investigate the incidence and distribution characteristics of dark without pressure (DWOP), a relatively underexplored retinal feature, in myopic people based on ultra-widefield swept source optical coherence tomography angiography (UWF-SS-OCTA) and ultra-wide field color fundus photography (UWF CFP). Methods: Subjects were recruited from December 2021 to May 2024 at Sichuan Provincial People's Hospital. Each eye underwent a comprehensive ophthalmic examination, including UWF CFP and 24×20 mm UWF-SS-OCTA. Eyes were categorized based on spherical equivalent (SE) into four groups: emmetropia, mild myopia, moderate myopia, and high myopia. Results: A total of 304 subjects (592 eyes) were recruited. The overall incidence of DWOP was 25.5%. It was significantly higher in the high myopia group (44.3%) compared to the emmetropia group (10.9%) ( p < 0.001). Axial length greater than 26 mm and SE less than -6.0 D were associated with increased DWOP risk. DWOP was predominantly found in the inferotemporal mid-periphery (68.9%). Retinal thickness in the DWOP region was 205.0 ± 13.6 μm, 1.70% lower than that in the normal region ( p = 0.001). Among the 34 eyes followed for 3 to 49 months, 52.4% of eyes showed an increase of DWOP area size, and 28.6% showed a decrease in area size. Conclusions: DWOP is commonly observed in high myopic eyes, primarily in the mid-peripheral inferior temporal region, with boundaries that change over time. These findings suggest a need for further investigation into the clinical significance of DWOP progression in myopic patients.