Classification and Prevalence of Early Senile Lens Opacities in Human Donor Eyes

Vrensen, G.; Willekens, B.

doi:10.1159/000417026

Cited by 17 publications

(13 citation statements)

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“…In an epidemiological survey on lenses collected from the Cornea Bank, Amsterdam, no significant correlation between cause of death and lens status was found: not even when the cause of death could be assumed to have been accompanied by long-term drug treatment, e.g. in cases of malignancy (Vrensen and Willekens, 1989). In addition, the lenses selected for the present study were clear with minimal nuclear discoloration and very few incipient opacities and were all of Caucasian origin.…”

Section: Methodological Considerationsmentioning

confidence: 58%

Ageing and changes in protein conformation in the human lens: A Raman microspectroscopic study

Siebinga

Vrensen

Otto

et al. 1992

Experimental Eye Research

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Using confocal Raman microspectroscopy with laser light of 660 nm the secondary and tertiary conformation of crystallins was studied in human lenses of varying age (20-75 years). Differences in cortical and nuclear proteins in individual lenses and among lenses of different age and differences between small equatorial opacities and adjacent clear sites were analysed using a difference spectrum approach. Intensity calibration allows assessment of local variations in protein content.The main findings and conclusions are as follows. (1) Irrespective of the age of the lens nuclear proteins proved to contain more aromatic amino acids, i.e. tryptophan, tyrosine and phenylalanine. This change most probably reflects differences in crystallin composition between nucleus and cortex as described in biochemical studies. (2) Changes in the amide bands indicate a more pronounced p-sheet conformation of the nuclear proteins. Taking into account available biochemical evidence this most probably reflects a true post-translational change in the secondary conformation of the crystallins. (3) Cortical proteins in 'old' and 'young' lenses are largely identical indicating that ageing is not accompanied by gross alterations in the transcription/translation of the crystallin genes. (4) 'Old' and 'young' nuclear proteins deviate with respect to the amount of aromatic amino acids, being more abundant in 'young' nuclear proteins. (5) Proteins in small early opacities do not exhibit alterations in conformation. (6) A pronounced peak in the difference spectra in the region 142 5-1435 cm-* for nuclear proteins especially when compared with equatorial cortical proteins may be considered as evidence for the advanced photooxidation of tryptophan and/or deamidation of asparagine from superficial to deep regions of the lens.

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Section: Methodological Considerationsmentioning

confidence: 58%

Ageing and changes in protein conformation in the human lens: A Raman microspectroscopic study

Siebinga

Vrensen

Otto

et al. 1992

Experimental Eye Research

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“…Vrensen and Willekens [8] showed that transparent lenses themselves reveal important information regarding their future processes. Later, Fujisawa and Sasaki [9] reported that light scattering intensity in lens layers detected from Scheimpfl ug slit images increased exponentially with age and estimated that the decreasing ratio might accelerate from as early as the middle 40s and there might exist racial differences .…”

Section: Discussionmentioning

confidence: 99%

Racial Differences of Lens Transparency Properties with Aging and Prevalence of Age-Related Cataract Applying a WHO Classification System

Sasaki

Sekiya²,

Jónasson³

et al. 2004

Ophthalmic Res

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Purpose: To investigate racial differences of lens transparency properties and the prevalence of lens opacification by age. Methods: Lenses of randomly selected Asian (1,038 Japanese and 517 Singaporeans) and Caucasian (1,045 Icelanders) subjects were evaluated for their lens transparency property (LTP). The prevalence of lens opacification was determined with a newly proposed WHO cataract classification system. Results: LTP increased with aging for all nationalities. Light scattering intensity was significantly higher in the Singaporeans followed by the Icelandic subjects. The prevalence of cortical opacification in Singaporeans was significantly higher than those of the other nationalities up to the age of 60, and the prevalence in Asians was significantly higher than that in Caucasians aged 60–69. Cortical opacification was more prevalent than the other types for both Japanese and Icelanders in their 50s, 60s and 70s. Regarding the central optical zone, the prevalence in the Singaporeans was significantly higher than in the other two groups in their 50s and 60s. The prevalence of nuclear opacification in Singaporeans was markedly higher than those of the two other groups for all ages. Subcapsular cataract was the least prevalent type for all age groups and nationalities; however, the highest prevalence was observed in Singaporeans. Conclusions: Lens transparency decreased with age in the Singaporeans more markedly than in the other two groups. The high prevalence of nuclear opacification in Singaporeans is considered to be due to environmental rather than race-specific factors.

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“…Small dot-like and spoke-like cortical opacities were found in 20 per cent in the age group of 31 -45 years and in 30 per cent in the age group 76-90 years. Larger segmental and annular cortical opacities were found in 10 per cent in the age group 31 -45 years and in 45 per cent in the age group 76-90 years [92]. While these cortical opacities can be either restricted to a sector or quadrant or found around the entire circumference of the lens, their extent is not directly related to lens age [90].…”

Section: Age-related Cataract (A) Forms Of Cataractmentioning

confidence: 93%

The ageing lens and cataract: a model of normal and pathological ageing

Michael

Bron

2011

Phil. Trans. R. Soc. B

394

288

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Cataract is a visible opacity in the lens substance, which, when located on the visual axis, leads to visual loss. Age-related cataract is a cause of blindness on a global scale involving genetic and environmental influences. With ageing, lens proteins undergo non-enzymatic, post-translational modification and the accumulation of fluorescent chromophores, increasing susceptibility to oxidation and cross-linking and increased light-scatter. Because the human lens grows throughout life, the lens core is exposed for a longer period to such influences and the risk of oxidative damage increases in the fourth decade when a barrier to the transport of glutathione forms around the lens nucleus. Consequently, as the lens ages, its transparency falls and the nucleus becomes more rigid, resisting the change in shape necessary for accommodation. This is the basis of presbyopia. In some individuals, the steady accumulation of chromophores and complex, insoluble crystallin aggregates in the lens nucleus leads to the formation of a brown nuclear cataract. The process is homogeneous and the affected lens fibres retain their gross morphology. Cortical opacities are due to changes in membrane permeability and enzyme function and shear-stress damage to lens fibres with continued accommodative effort. Unlike nuclear cataract, progression is intermittent, stepwise and non-uniform.

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Classification and Prevalence of Early Senile Lens Opacities in Human Donor Eyes

Cited by 17 publications

References 0 publications

Ageing and changes in protein conformation in the human lens: A Raman microspectroscopic study

Ageing and changes in protein conformation in the human lens: A Raman microspectroscopic study

Racial Differences of Lens Transparency Properties with Aging and Prevalence of Age-Related Cataract Applying a WHO Classification System

The ageing lens and cataract: a model of normal and pathological ageing

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