*Old and well-functioning*;
Determinants of PReservation Of Function in ELderly

According to the majority of older people preservation of physical and
psychosocial functioning is important in their live. However, two third of
older people have one or more chronic disease, with a mean number of conditions
of 2.5. For older people these chronic conditions become problematic as soon as
these conditions threat daily live activities and vitality. Functional decline
and loss of vitality can change the balance in daily living negatively with the
risk of a cascade breakdown. This group of older people is vulnerable; this
vulnerability is often defined as *frailty*. Although frailty is studied in a
growing number of studies, the pathway to frailty is almost unknown. Age,
disease, loss of muscle mass and bone mineral density are considered as key
factors in the process of frailty. The lack of understanding of the physiology
and etiology of frailty causes a problem in the development of effective
preventive interventions. Preventive interventions could enable people, even in
old age and with chronic conditions, to live independently the life they choose
to live. Cardiovascular diseases (CVD) such as coronary ischemic disease, heart
failure and cerebrovascular accidents are prominent among the chronic
conditions that predispose elderly people to functional limitations and
disability. Because of the aging of the population, the number of people with
functional limitations and disability will only increase.

Many elderly develop one or more eye conditions threatening that independency.
A decline in visual functioning and eye disease change the balance in daily
life with potential drastically consequences: increased dependency on others
and potential admission to a nursing home.

Several aspects of visual functioning are affected by geriatric (old age)
disease or ocular complications of chronic disease, such as visual acuity,
visual field, contrast sensitivity, refraction, or glare. Exact numbers of
visual challenges of independent living elderly are lacking as ocular changes
are not routinely registered in physician*s registries and patients are not
routinely screened nor do they seek medical care as they consider visual
decline a normal deterioration with age. The impact of visual impairment and
effects of even *normal* age-related functional decline may therefore be
underestimated.

To our knowledge, no study addressed the effect or combined effect of several
visual aspects including straylight (glare) and ocular health on activities of
daily living in independently living elderly.

The aim of this project is to gain insight in which somatic, cognitive and
psychosocial
factors contribute to preservation of functioning, in order to identify older
people with potential
risk of functional decline in an early stage and develop interventions to
prevent or delay
functional decline to enable older people to stay independent and able to take
care of themselves.

The aim of the additional study is to gain insight in which factors (i.e.
somatic, psychosocial) contribute to the preservation of visual functioning and
in which aspects of vision influence the individual*s well being with respect
to physical, social and mental functioning. The knowledge will enable the
development of preventive interventions in older people to stay independent and
take care of themselves.

a longitudinal population-based study

The participants will be invited for 3 visits, because the program
(measurements, tests and questionnaires) will be too intensive for 1 day. The
third visit will be at a different location. Fasting bloodsamples will be
collected and the six minute walking test will be performed. No serious adverse
events were reported in numerous of studies. In only a small percentage of the
participants dizziness and nausea were reported.
During the third visit pupillary dilation eye drops will be administered. Due
to that, participants may experience photophobia (1-4 hours). Therefore, all
participants will receive free transportation to and from the research center.