Multimodal imaging of dark without pressure in high myopia reveals evidence that photoreceptor microscopic lesions may be reversible.

Dark without pressure (DWP) is the more darkly pigmented area of the retina in the fundus, typically exhibits relatively distinct boundaries, and varies in shape, size, and distribution across different individuals. Previous studies have concluded that DWP alone has no impact visual acuity, visual field, or other visual functions. This study aims to reveal the multimodal imaging manifestations of DWP in high myopia and to explore its impact on retinal function. This is a prospective study. Eleven high myopia patients with DWP were recruited. Detailed ophthalmological examinations, such as visual acuity, intraocular pressure, slit lamp microscope, and fundoscopy, were performed in all participants to exclude other ocular diseases or retinopathies. Multimodal imaging including swept source optical coherence tomography (SS-OCT), adaptive optics (AO) fundus imaging was applied to analyze morphologic manifestations of DWP. Retinal photosensitivity was detected by perimetry or microperimetry. Eight of the participants were followed for at least 5 months and up to 32 months. The DWP appeared as water trace pattern that was darker in color than the surrounding normal fundus. The punctate light reflectivity of the photoreceptor mosaic in AO fundus imaging was missing, and the light reflectivity in ellipsoid zone (EZ) of SS-OCT B scan was attenuated or even disappeared simultaneously. Perimetry revealed reduced retinal photosensitivity in the DWP lesions. At 5-month follow-up, the area of DWP lesions could appear to expand or shrink. Where the DWP faded away, the reflectivity of EZ on SS-OCT returned to normal hyperreflectivity, accompanied with a recovered retinal photosensitivity. The imaging basis for DWP in high myopia is the presence of microscopic lesions in the outer retina which could be shown morphologically with optical imaging and functionally with microperimetry. It is variable in size and may be reversible in function in the fundus.