Instrumental Activities of Daily Living Tools in Very-Low Vision: Ready for Use in Trials?

Area of Science:

• Ophthalmology
• Rehabilitation Science
• Clinical Trials

Background:

• Traditional visual function assessments often lack sensitivity to detect improvements from vision restoration interventions.
• Instrumental Activities of Daily Living (IADL) offer a functional outcome measure relevant to patients with vision impairment.
• Several vision-specific IADL instruments exist, but their suitability for vision restoration trials requires evaluation.

Purpose of the Study:

• To review existing vision-specific IADL instruments for their utility in vision restoration trials.
• To present validation data for the most promising IADL instruments, specifically the Very Low Vision IADL (IADL-VLV).

Main Methods:

• A systematic review of vision-specific IADL instruments was conducted.
• Internal consistency, test-retest reliability, content validity, and construct validity were assessed for relevant instruments.
• The Very Low Vision IADL (IADL-VLV) was further validated in a low-vision clinic sample (n=51).

Main Results:

• Six instruments were identified: LVFSE, TIADL, MLVAI, ADREV, FLORA, and IADL-VLV.
• The IADL-VLV demonstrated high test-retest reliability (ICC=0.981).
• The MLVAI and IADL-VLV were specifically developed for ultra-low vision contexts and showed better reliability than LVFSE. Ceiling effects were noted across instruments.

Conclusions:

• The IADL-VLV and MLVAI are the most suitable IADL instruments for vision restoration trials, including those involving gene therapy or visual prostheses for inherited retinal diseases.
• Further validation of these instruments is necessary to confirm their efficacy in diverse patient populations and intervention types.