FLORA™: Phase I development of a functional vision assessment for prosthetic vision users

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Rehabilitation Science

Background:

• Developing effective functional assessments is crucial for evaluating vision restoration treatments in ultra-low vision populations.
• The Argus II Retinal Prosthesis System offers partial vision restoration, necessitating tools to measure its impact.
• Existing assessments may not be suitable for individuals with severe to profound vision loss.

Purpose of the Study:

• To develop and pilot a functional assessment for ultra-low vision individuals undergoing vision restoration.
• To capture functional visual ability and well-being in subjects implanted with the Argus II Retinal Prosthesis System.
• To determine the appropriateness of assessment tools and identify potential floor or ceiling effects.

Main Methods:

• The Functional Low-Vision Observer Rated Assessment (FLORA) was developed, incorporating self-report, observed functional tasks, and narrative summaries.
• Twenty-six subjects with severe to profound retinitis pigmentosa, implanted with the Argus II System, were assessed by seven evaluators.
• Analysis focused on the suitability of interview questions and tasks, and the presence of rating scale limitations.

Main Results:

• All 14 interview questions were utilized, and all 35 functional vision tasks were selected for evaluation at least once.
• Evaluators used all four rating options (impossible, difficult, moderate, easy), indicating a lack of floor or ceiling effects.
• Subjects utilized 'vision only' 75% of the time with the Argus II System ON, compared to 29% with the System OFF.

Conclusions:

• The initial version of the FLORA assessment demonstrated utility and avoided floor and ceiling effects in an ultra-low vision population.
• The assessment successfully captured functional vision and well-being in subjects using the Argus II Retinal Prosthesis System.
• Future development will focus on refining the FLORA and establishing its reliability and validity for enhanced clinical use.