“Low incidence disability” means a severe disabling condition with an expected incidence rate of less than one percent of the total statewide enrollment in kindergarten through grade 12. For purposes of this definition, severe disabling conditions are hearing impairments, vision impairments, and severe orthopedic impairments, or any combination thereof. For purposes of this definition, vision impairments do not include disabilities within the function of vision specified in Section 56338.
Source:
Section 56026.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=EDC§ionNum=56026.5..