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Target Concepts:
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Query: UMLS:C0851184 (
thinning
)
11,252
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
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 conjunctiva 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.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:The Basel longitudinal study on aging (1955-1978). Ophthalmo-gerontological research results. 362 22
The pathologic basis for
presbyopia
is classically attributed to lenticular sclerosis or atrophy of the ciliary muscle, but recent work suggests that thickening and loss of elasticity of the anterior lens capsule play an important role. As no practical means for attenuating or reversing the aging process of lens protein has been identified, alteration of the lens capsule eventually might prove to be a desirable alternative to spectacle correction in presbyopic individuals. This paper describes changes in the refractive properties of the lens resulting from alteration of the anterior lens capsule by application of focal cautery, using both an in vitro, in situ and an in vivo rabbit model. In vitro thermal treatment (electrocautery) of the capsule significantly increased the anterior curvature of the lens by an average of +2.95 diopters. Histologic examination of the treated lenses showed
thinning
of the capsule in the treated areas, as well as focal vacuolar degeneration in the lens substance beneath the lesions. In vivo thermal treatment of eyes induced a significant shift toward myopia, compared with control eyes. The accommodative range increased post-treatment relative to the controls, but the effect diminished over time, stabilizing near baseline at two to three weeks after treatment. Histologic examination showed localized changes but no signs of diffuse cataract formation. We conclude that the anterior capsule may play a significant role in the refractive power and accommodative changes in the crystalline lens.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Refractive changes induced by electrocautery of the rabbit anterior lens capsule. 820 61