The Basel longitudinal study on aging (1955?1978)

Abstract

In the prospective Basel longitudinal study on aging (1955–1978) 123 men (age at entry from 6–61 years) were investigated in 2 year (average) intervals. Complete case histories are available on 67 subjects over the entire period (19.6 ± 0.85 years). Part I of the study was to confirm the hypothesis of Bernstein and of Steinhaus, according to which life expectancy can be estimated from the speed of development of presbyopia. Parallel to the measurement of accommodation range (after preliminary determination of refraction and visual acuity), the development of height, body weight, vital capacity, expiratory volume, chest circumference, abdominal circumference, blood pressure, ECG and pulse wave velocity were measured. Invasive investigations were not undertaken. Only when hypertension was combined with obesity was the diminution of accommodation range striking (Fig. 10c; however there were only 3 subjects in this risk group). Taking everything into consideration there was a concomitance between decrease of accommodation range and changes of medical parameters (Table 6). Intercurrent illness did not influence the accommodation range. Longitudinal measurements and cross-sectional comparisons (data averaged to the same point as of the same age) were carried out. The results did not always coincide. We could not confirm the hypothesis of Bernstein and of Steinhaus. In Part II the results of the objective measurements are given. Apparently growth of the skull does not stop entirely. The increase of interpupillary distance can be complete at 17 years of age, but also can continue to the 30th year. The palpebral fissure increases an average of 3 mm more horizontally between the 6th and the 20th year of life. The corneal diameter remains constant in all age classes, that is, the growth of the cornea should be complete before the 6th year of life. Early arcus senilis changes are found already in the 20-year-old. The increase in the course of time of arcus senilis is obvious, it is most pronounced in obese hypertensives. Still there are persons who at 65 years of age show no arcus senilis. In the 20th year degenerative deposits in the conjuctiva begin. They increase in number and above the 60th year all subjects showed degenerative deposits. Aqueous veins are less visible in younger subjects. With increasing age — as a result of degenerative thinning of the conjunctiva — they are recognizable in ever greater numbers. The depth of the anterior chamber attains its greatest extent between the 20th and the 30th year. After this it decreases again due to the continued growth of the lens with the size of the eye remaining constant (with occasional exceptions). Myopic eyes have a deeper anterior chamber than hyperopic eyes. With lateral asymmetry of the anterior chamber of a subject, the left anterior chamber was deeper than the right chamber more frequently than the other way around. Signs of cataracta senilis incipiens appeared in our subjects only after the 50th year. Only 1 subject (age 66) underwent cataract surgery during the observation period. There was no dependence of any of the parameters mentioned on another. Repeated photography of the anterior surface of the iris during 20 years showed a constant coarse as well as fine structure. Changes such as described by practitioners of ‘iris diagnosis’, were not noted even in the 40 cases who experienced more or less serious health changes. The photography of the healthy iris can serve for identification of the individual just like his fingerprint. Interesting in our case material in the longitudinal analysis, is the analogous finding with respect to the ECG: the form of the QRS complex remains unchanged during the entire lifetime in a form specific to the individual (Gsell et al., 1986). The surface of the optic disc, just as its brightness, did not change during 8 years in healthy adults. Ophthalmoscopy of the retinal vessels has subjective uncertainties. Clear narrowing of caliber and sharpening of the light reflex were recorded during 20 years only in the obese hypertensives. The retinal vessels, measured according to the method of Kagan et al. (1967) showed a physiological trend toward decrease in length. The stereochronoscopic analysis of all colored photographs of the fundus showed in 6 cases over 8–11 years longitudinal changes: formation and clearing of deposits (possibly cholesterol); stretching of circumpapillary vessels in 2 cases of progessive myopia; striking decrease in vessel length in one case of presenile sclerosis of fundal vessels; narrowing on one hand and passive stretching of arteries on the other hand in one case of accelerated hypertension; positional changes of the circumpapillary vessels between the 70th and the 80th year of life in one emmetropic eye (and not in the partner's eye!), which 50 years previously had suffered a perforating glass splinter injury. Long term 'movements; of the retinal vessels should be given further attention.