The Northern Ireland Sensory Ageing Study
Condition: Aging
Study type: Observational

Summary: 
      A visual function focused add-on study to the Northern Ireland Cohort for the Longitudinal
      Study of Ageing (NICOLA). There are three key aims:

        1. Quantify age-related decline in a variety of visual functions within a populations based
           cohort.

        2. Explore the mechanisms underlying age-related visual impairments.

        3. Investigate how visual function impacts vision related quality of life.
    

Detailed description: 
      The investigators propose to put together a battery of test to assess different aspects of
      visual function and apply them to two groups of participants in order to explore differences
      in chronological and physiological aging.

      Group 1: 25 participants from each decade from 20-90. Those from 50+ will be recruited from
      the NICOLA study and retinal/lens images assessed to confirm normality (drusen <63µm or clear
      retina, LOCS III <1). Those younger will be recruited via advertisements in the University
      and targeting friends and relatives or NICOLA participants. This will enable the rate of
      decline with age to be calculated. Linear, bilinear, and simple nonlinear candidate functions
      of parameter vs. age will be applied to determine which best characterises the change.

      Group 2: 250 participants NICOLA participants aged 60 will be invited to participate; only
      those whose ocular images confirm normality will be included. This will enable mechanisms
      underlying individual differences in aging to be investigated. Normal aging will be
      determined from group 1 analysis and participants will be able to be categorised as aging
      well or aging poorly. Multivariate regression analysis will be used to investigate the
      relationship between visual function and lifestyle and environmental factors. Principal
      components analysis will be used to look at the relationships between visual parameters.
      These participants will also be asked to complete the NEIVFQ-25, to characterise visual
      function related quality of life and this will be compared with their measured visual
      function.

      Visual function parameters measured after protocol refraction will include: Photopic and
      mesopic visual acuity and contrast sensitivity using City Occupational acuity-plus
      software17, near visual acuity, reading speed and SKILL card18, MAIA microperimetry and cone
      dark adaptation.19 Intra-ocular scatter will be assessed using the Oculus C-quant to assess
      the extent to which ocular factors are degrading vision.20 Three-point vernier acuity will
      also be measured as this is thought to stay stable throughout life.15 Time will be taken to
      ensure participants receive sufficient training to produce reliable thresholds.

      All study visits will occur at the Welcome-Wolfson Clinic Research Facility.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        25 participants from each decade from 20-90. Those from 50+ will be recruited from the
        NICOLA study. 250 participants NICOLA participants aged 60 will be invited to participate;
        only those whose ocular images confirm normality will be included.
      
Biospecimen description: 
      Blood sample.
    
Keywords: Visual Nonspecific