The severity rating scales support consistency in determining service delivery times for students who are Blind or Visually Impaired. Use the scales to establish how often a particular service should be delivered to a student. The Vision Services Severity Rating Scale was updated in 2024. For more information about the updated document, watch LIVE with LIO: Using the New Severity Rating Scale.

Vision Services Severity Rating Scale (VSSRS)


For visual impairment services delivered by teachers and teacher consultants.

Download VSSRS [PDF]

Orientation & Mobility Severity Rating Scales (O&MSRS)


For orientation and mobility services.


For orientation and mobility services delivered to students with additional needs.