The patient’s eyes see things very darkly, which may be caused by eye trauma, cataract, retinitis pigmentosa and so on. 1. Ocular trauma: patients with ocular trauma may experience discomfort such as dimmed vision and small size due to vitreous hemorrhage, retinal detachment and macular edema. 2. Cataract: Cataract refers to the visual impairment disease caused by decreased transparency or color change of the lens. When the transparency of the patient’s lens decreases with aging, the contrast sensitivity of the eyes decreases, and the patient may have the symptom of darkness in the eyes. 3. Retinitis pigmentosa: Retinitis pigmentosa belongs to the hereditary photoreceptor cell function abnormality disease, patients may have poor night vision, the field of vision gradually shrinking symptoms. Due to the abnormalities in the retina, patients may also have the symptom of dark vision. It is recommended that patients with dark vision and other discomforts should consult a doctor for evaluation of their condition and follow the doctor’s instructions for treatment.