What is the estimated visual field for this subject after 20 years of follow-up? Provide a 95% confidence interval associated with this estimate.

Ophthalmology

Retinitis pigmentosa (RP) is a hereditary ocular disease in which patches of pigment appear on the retina, potentially resulting in substantial vision loss and in some cases complete blindness. An important issue is how fast the subjects decline. Visual field is an important measure of area of vision, which is measured in degree². A visual field area for a normal person is around 11,000 degree². The longitudinal data in Table 11.29 were provided by an individual patient.

Table 11.29: Longitudinal visual field data for one RP patient

 

Suppose the rate of change of ln (visual field) is a linear function of follow-up time.

Transcribed Image Text:

Visual field area (degree") Time In Visit (yr) (visual field area) 3059 8.03 2 3053 8.02 1418 7.26 4 3 1692 7.43 4 1978 7.59 1567 7.36 1919 7.56 1998 7.60 11 1648 7.41 10 13 1721 7.45 11 15 1264 7.14 7.532 6.09 1938 mean sd 4.97 597 0.280