Visual impairment is a form of visual loss that interferes with an individual’s daily activities of living and is secondary to a functional etiology in the eye or visual system. Based on the patient’s visual acuity and visual field, visual impairment can be classified mainly into two main categories: moderate visual impairment, defined as a best-corrected visual acuity (BCVA) between 20/70 to 20/200 or a visual field of ≤ 20 degrees diameter in the better-seeing eye, and legal blindness, defined as a BCVA between ≤ 20/200 or a visual field of ≤ 20 degrees diameter in the better-seeing eye.