A large difference in vision between the two eyes may be due to a problem in the bare eye vision resulting in refractive aberration, which requires a dilated eye exam to see whether it is myopia, hyperopia or astigmatism, which can be corrected in time by wearing glasses or corneal contact lenses and surgery, but may also be caused by cataracts or retinopathy in one eye. Refractive parallax is called physiological refractive parallax if the refraction of both eyes is less than 1.00D, while visual problems may occur if the refraction is greater than 1.00D. Since human eye activity is binocularly equivalent, if one eye has better vision and can focus clearly, and the other eye has poor vision and blurred vision, the eye is easily called the weak eye. The difference in visual acuity between the two eyes is large, the received imaging cannot be fused and is prone to bilateral functional abnormalities. 1, children: children with refractive disparity are preferred to wear frame glasses, which should be worn throughout the day. As children’s eyes are still developing, it is not recommended to choose refractive surgery treatment; 2, adults: adult patients are also preferred to frame glasses for correction, if dizziness occurs after wearing glasses, you can choose to correct isotropic lenses, for patients who have not been corrected for a long time can alternate gaze to improve. For patients who cannot wear glasses or are unwilling to wear glasses, they can choose IOL implantation to improve the symptoms of refractive disparity in both eyes. The early symptoms of cataract are not obvious and may only be blurred vision, but with the development of the disease, myopia and glare may appear, and with the aggravation of the disease, heavy cases may lead to blindness. 1. Surgery: When the vision is lower than 0.4, it is necessary to consider surgery to treat cataract, which requires a professional doctor to develop a surgical plan according to individual conditions, such as ultrasonic cataract aspiration or IOL implantation. Third, monocular retinopathy such as retinal detachment, macular degeneration, diabetic retinopathy, etc., may produce black shadows floating and cloudy shadows often in the visual field, or even a sharp decrease or complete loss of vision. Surgical treatment is usually required, such as extra-scleral ring ligation pad pressure, vitrectomy retinal repositioning, etc.