These guidelines address the need for valid and reliable measures to aid in making decisions on teaching of braille and/or print to students with moderate to severe vision losses. After an introductory section, section 1 presents basic principles organized into the following categories: (1) learning media, (2) students who use the learning media, (3) selection of learning medium/media, and (4) use of learning media in educational settings. Section 2 addresses assessment and evaluation, detailing both individual child attributes to be measured and educational and noneducational environmental attributes to be measured. Section 3 presents 16 guidelines for decision making in selection of learning media. These include: low vision children must have annual low vision evaluations; some children show definite preferences for either visual or tactual learning at an early age; some low vision students may utilize both braille and print for selected purposes; keyboarding and auditory materials are valuable supplements; and flexibility is the key to the use of all types of media for maximum literacy. An appendix contains data on the prevalence of visual impairment, reading media and program type, and reading speeds of visually impaired students, and American Printing House distribution of federal quota based on the registration of eligible students, 1988-1990. A second appendix contains additional information by national organizations and a list of functional vision assessment instruments, and a chart which defines the levels of visual disability discussed in section 3. (Section 3 and Appendix B contain bibliographies with a total of 33 items; section 3 contains 26 additional references. (DB)