In 2A Questionnaire 2, adult Lifelines participants filled in questionnaire about eye conditions, developed by the Department of Ophthalmology at the UMCG (section: diseases & symptoms).
The questionnaire contained both general questions and questions from validated ophthalmological instruments:

• VISION1-5: general questions on vision aids
• VISION6-24: questions derived from part 1 and 2 of the Visual Functioning Questionnaire (VFQ-25/NL) on visual impairments and related functional limitations / quality of life
• VISION25A/B: general questions about the diagnosis of macular degeneration and glaucoma
• VISION26-28: questions derived from the Short Questionnaire for Dry Eye Syndrome (SQ-DES) (DES or Keratoconjunctivitis sicca).
• VISION29-30: general questions about (laser) eye surgery
• VISION31A1-5: general questions about the use of eye drops or gel

The VFQ-25 is a vision-specific measure of helth-related quality of life, composed of eight multi-item scales, four single-item scales, and one composite score ranging in value from 0 (poor) to 100 (high).
The following dimensions of vision-targeted function and HRQoL comprise the VFQ-25:

• overall vision
• difficulty with near vision activities
• difficulty with distance vision activities
• limitations in social functioning due to vision
• role limitations due to vision
• dependency on others due to vision
• mental health symptoms due to vision
• driving difficulties
• limitations with peripheral and colour vision
• ocular pain.

Mangione et al. (1998)¹⁾ was the first to show that the NEI-VFQ is reliable and valid. They showed that the psychometric properties of the NEI-VFQ were not influenced by the type or severity of the underlying eye disease, suggesting that the measure will provide reproducible and valid data when used across multiple eye conditions.
The VFQ-25 has additionally been shown to be valid and reliable in several populations and eye diseases ^2)3)4)5)6)7)

In Lifelines a subset of the VFQ-25 was used and there is no information available regarding validity and reliability.

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6-point scale: no difficulty at all, a little difficulty, moderate difficulty, extreme difficulty, stopped doing this because of your eyesight, stopped doing this for other reasons or not interested in doing this)

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