Visual impairment varies greatly. A person is considered legally blind when visual acuity is 20/70 or less in the better eye with the use of corrective lenses. The term blindness can be reserved for those with total loss of sight, and visually impaired can refer to people with various gradations of vision. Most people considered legally blind have some vision. Others who have low vision may rely on residual vision with the use of adaptive equipment. Persons who are totally blind may have visual memory, the utility of which varies depending on the age when vision was lost.
Whatever the degree of impairment, students who are visually impaired can participate fully in classroom activities, discussions and group work. To record notes, some use laptop computers or computerized Braillers. Students who are visually impaired may encounter difficulties in laboratory classes, field trips and internships. With planning and adaptive equipment, these difficulties can be minimized.