NoIR SpectraShield dark gray (filter 22) Sunglasses offer 100 percent ultraviolet protection, 11 percent light transmission and 100 percent blue light protection. They heighten contrast, feature maximum brightness and good visual acuity. The SpectraShield frame has a ledge at the top to keep the sun or light from beaming in and it has the same filter within the small windows on the sides of the frame. The NoIR SpectraShield frame offers complete protection from the sun and artificial lighting. These sunglasses can be worn alone or over prescription glasses. Offered in medium which measures approximately 6.1 inches wide. Useful for those with glaucoma, diabetic retinopathy, and post op cataract conditions.