An optometric technician works under the supervision of an optometrist or ophthalmologist. Instructors train students to work in eye care under the supervision of optometrists and ophthalmologists. Instruction emphasizes the unique duties required of an optometric technician to provide quality vision care services to patients. The technical training includes optical terminology; optical properties of light; patient pretesting skills such as tonometry, keratometry, visual acuity, color vision, visual field testing and blood pressure; frame and lens selection; eyeglass adjustment; contact lens patient education; ocular anatomy and physiology; visual training and practice management. Clinical experience working directly with doctors and patients is an important part of the curriculum.