The assessment of visual impairment has been significantly revised from the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition. The Fifth Edition, Chapter 12, The Visual System, bases ratings on an estimate of the severity of the effects of certain types of visual loss on the ability to perform activities of daily living (ADLs). Permanent visual impairment is defined as a permanent loss of vision that remains after a patient reaches maximal medical improvement in the underlying medical condition. To assess vision loss, physicians must conduct a visual assessment, including the cause, severity, and prognosis of the underlying disorder and the expected or documented effects of the vision loss on the patient's ability to perform ADLs. Tables in Chapter 12 guide the assessment of visual impairment and consider the results of visual acuity testing, acuity-related impairment rating, and associated classifications. Table 12-10, Classification of Impairment of the Visual System and of the Whole Person, uses clinical data to classify the individual in one of six classes associated with a range of whole person impairment. According to the Fifth Edition of the AMA Guides, examining ophthalmologists or optometrists are required to have new visual acuity charts, appropriate visual field testing equipment, and other equipment for testing contrast sensitivity and glare tests as needed.