What's a major cause of vision loss in people above 40 years old?

Adults over 40 years old are at risk of developing serious eye diseases leading to vision loss. The major ones include cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy. Glaucoma is asymptomatic and causes damage to the optic nerve leading to loss of visual field. Age-related macular degeneration leads to loss of central vision. Diabetic retinopathy is found in patients with diabetes and can lead to blurry or distorted central vision. Cataract causes impairment of vision or glare since the lens becomes cloudy.