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Article ; Online: Biometry of the human cornea and globe: An evaluation by age, gender and population.

Augusteyn, Robert C / Mohamed, Ashik

2022 Volume 216, Page(s) 108932

Abstract: The purpose of this study was to examine the effects of age, gender and population origin on human globe and corneal dimensions and to explore the relationships between the dimensions. Human post-mortem eyes were obtained in Hyderabad (n = 223; range, 0- ... ...

Abstract	The purpose of this study was to examine the effects of age, gender and population origin on human globe and corneal dimensions and to explore the relationships between the dimensions. Human post-mortem eyes were obtained in Hyderabad (n = 223; range, 0-85 years) and Miami (n = 486; range, 6-103 years). The eyes were freed of extraneous tissues and globe antero-posterior length (GAPL), mean globe diameter (MGD) (average of horizontal and vertical), and corneal horizontal (HCD) and vertical (VCD) diameters were measured using digital calipers. The relationships of age, gender and population origin with globe and corneal dimensions and the relationships between the dimensions were assessed by bivalent and multiple regression analyses. Globe and cornea dimensions increase asymptotically with age until around the late teens but do not change thereafter. Bivariate and multivariate regression analyses of the >20-year-old eyes showed that population was significantly correlated with GAPL, MGD, HCD and VCD. Male globes and corneas were larger than those from females, but the difference did not appear to be statistically significant. All Hyderabad dimensions were significantly larger than those from the Miami. Neither GAPL nor MGD were correlated with the corneal dimensions. GAPL was significantly correlated with MGD as was HCD with VCD.
MeSH term(s)	Adolescent ; Adult ; Aged ; Aged, 80 and over ; Aging/physiology ; Axial Length, Eye/anatomy & histology ; Biometry/methods ; Child ; Child, Preschool ; Cornea/anatomy & histology ; Cornea/growth & development ; Eye/anatomy & histology ; Eye/growth & development ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Sex Factors ; Tissue Donors
Language	English
Publishing date	2022-01-15
Publishing country	England
Document type	Comparative Study ; Journal Article ; Multicenter Study ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	80122-7
ISSN	1096-0007 ; 0014-4835
ISSN (online)	1096-0007
ISSN	0014-4835
DOI	10.1016/j.exer.2022.108932
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Article ; Online: On the contribution of the nucleus and cortex to human lens shape and size.

Augusteyn, Robert C

Clinical & experimental optometry

2017 Volume 101, Issue 1, Page(s) 64–68

Abstract: Background: The shape of the human lens changes from almost spherical at birth to ellipsoid due to a decrease in sagittal thickness and an increase in equatorial diameter during the first two decades of life. Both dimensions increase thereafter. This ... ...

Abstract	Background: The shape of the human lens changes from almost spherical at birth to ellipsoid due to a decrease in sagittal thickness and an increase in equatorial diameter during the first two decades of life. Both dimensions increase thereafter. This study was undertaken to determine the reason for the change. Methods: Published refractive index gradients, from 20 lenses aged from seven to 82 years, were used to calculate the protein contents of concentric shells of fibre cells in human lenses. The boundaries of nuclear cores containing from 2.5 to 45 mg, in 2.5 mg increments, were determined from the isoindicial shells. Cortex thickness was determined from the distance between the 30 mg nuclear boundary and the capsule. Results: The sagittal thickness of every nuclear core decreased until age 40 years and remained constant thereafter. Over the same time frame, the equatorial diameter of the cores containing up to 30 mg of protein increased, while those of cores larger than 30 mg decreased. The volumes of the cores decreased and their shapes changed from near spherical to spheroidal. Equatorial and sagittal cortex thickness increased linearly with age at 0.0082 mm per year. The anterior sagittal cortex was 0.23 mm larger than the posterior and the equatorial cortex was 0.62 mm greater. Conclusions: Changes in lens shape observed during the first two decades of life are due to remodelling and compaction of the 30 mg nuclear core. Cortex growth is linear throughout life.
MeSH term(s)	Adolescent ; Adult ; Aged ; Aged, 80 and over ; Aging ; Child ; Humans ; Lens Cortex, Crystalline/anatomy & histology ; Lens Cortex, Crystalline/growth & development ; Lens Nucleus, Crystalline/anatomy & histology ; Lens Nucleus, Crystalline/growth & development ; Middle Aged ; Organ Size ; Young Adult
Language	English
Publishing date	2017-03-30
Publishing country	Australia
Document type	Journal Article
ZDB-ID	639275-1
ISSN	1444-0938 ; 0816-4622
ISSN (online)	1444-0938
ISSN	0816-4622
DOI	10.1111/cxo.12539
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Article ; Online: Growth of the eye lens: II. Allometric studies.

Augusteyn, Robert C

Molecular vision

2014 Volume 20, Page(s) 427–440

Abstract: Purpose: The purpose of this study was to examine the ontogeny and phylogeny of lens growth in a variety of species using allometry.: Methods: Data on the accumulation of wet and/or dry lens weight as a function of bodyweight were obtained for 40 ... ...

Abstract	Purpose: The purpose of this study was to examine the ontogeny and phylogeny of lens growth in a variety of species using allometry. Methods: Data on the accumulation of wet and/or dry lens weight as a function of bodyweight were obtained for 40 species and subjected to allometric analysis to examine ontogenic growth and compaction. Allometric analysis was also used to compare the maximum adult lens weights for 147 species with the maximum adult bodyweight and to compare lens volumes calculated from wet and dry weights with eye volumes calculated from axial length. Results: Linear allometric relationships were obtained for the comparison of ontogenic lens and bodyweight accumulation. The body mass exponent (BME) decreased with increasing animal size from around 1.0 in small rodents to 0.4 in large ungulates for both wet and dry weights. Compaction constants for the ontogenic growth ranged from 1.00 in birds and reptiles up to 1.30 in mammals. Allometric comparison of maximum lens wet and dry weights with maximum bodyweights also yielded linear plots with a BME of 0.504 for all warm blooded species except primates which had a BME of 0.25. When lens volumes were compared with eye volumes, all species yielded a scaling constant of 0.75 but the proportionality constants for primates and birds were lower. Conclusions: Ontogenic lens growth is fastest, relative to body growth, in small animals and slowest in large animals. Fiber cell compaction takes place throughout life in most species, but not in birds and reptiles. Maximum adult lens size scales with eye size with the same exponent in all species, but birds and primates have smaller lenses relative to eye size than other species. Optical properties of the lens are generated through the combination of variations in the rate of growth, rate of compaction, shape and size.
MeSH term(s)	Animals ; Body Weight ; Humans ; Lens, Crystalline/anatomy & histology ; Lens, Crystalline/growth & development ; Organ Size ; Phylogeny
Language	English
Publishing date	2014-03-30
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	2017540-1
ISSN	1090-0535 ; 1090-0535
ISSN (online)	1090-0535
ISSN	1090-0535
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Article ; Online: Growth of the eye lens: I. Weight accumulation in multiple species.

Augusteyn, Robert C

Molecular vision

2014 Volume 20, Page(s) 410–426

Abstract: Purpose: To examine the accumulation of wet and/or dry weight in the ocular lens as a function of age in different species.: Methods: Wet weights and/or fixed dry weights were obtained from measurements in the author's laboratory and from the ... ...

Abstract	Purpose: To examine the accumulation of wet and/or dry weight in the ocular lens as a function of age in different species. Methods: Wet weights and/or fixed dry weights were obtained from measurements in the author's laboratory and from the literature for over 14,000 lenses of known-ages, representing 130 different species. Various algorithms were tested to determine the most suitable for describing the relationship between lens weight and age. Results: For 126 of the species examined, lens growth is continuous throughout life but asymptotic and can be reasonably described with a single logistic equation, W=Wm e(-(k/A)), where W is lens wet or dry weight; Wm is the maximum asymptotic weight, k is the logistic growth constant and A is the time from conception. For humans, elephants, hippopotami, minks, wild goats and woodchucks, lens growth appears to be biphasic. No gender differences could be detected in the lens weights for 70 species but male lenses are reportedly 10% larger than those of females in northern fur seals and pheasants. Dry weight accumulation is faster than that for wet weight in all species except birds and reptiles where the rates are the same. Low lens growth rates are associated with small animals with short gestation periods and short life spans. Conclusions: Lens growth is continuous throughout life and, for most species, is independent of gender. For most, growth takes place through a monophasic asymptotic mode and is unaffected by events such as hibernation. This makes lens weight measurement a reliable tool for age determination of species culled in the wild. Compaction of the growing lens generates different properties, appropriate to an animal's lifestyle. How these events are controlled remains to be established.
MeSH term(s)	Aging/physiology ; Animals ; Female ; Humans ; Lens, Crystalline/anatomy & histology ; Lens, Crystalline/growth & development ; Logistic Models ; Male ; Organ Size ; Species Specificity
Language	English
Publishing date	2014-03-29
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	2017540-1
ISSN	1090-0535 ; 1090-0535
ISSN (online)	1090-0535
ISSN	1090-0535
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Article ; Online: Human lens weights with increasing age.

Mohamed, Ashik / Augusteyn, Robert C

Molecular vision

2018 Volume 24, Page(s) 867–xxx

Abstract: ... for 1 week, and then dried at 80 °C until a constant weight was achieved.: Results: Wet and dry lens ...

Abstract	Purpose: To evaluate the changes with age in human lens wet and dry weights. Methods: All procedures were performed by the same person in the same environment. Lenses were extracted from donor eyes within a median post-mortem time of 22 h, blotted dry and weighed within 30 min, immediately placed in fixative for 1 week, and then dried at 80 °C until a constant weight was achieved. Results: Wet and dry lens weights were obtained from 549 human lenses. Before age 2 years, most of the weight increases are due to a self-limiting process and can be described with logistic equations. The maximum asymptotic wet and dry weights for male lenses are 6.0 and 1.77 mg, respectively, heavier than those for female lenses. After age 3 years, male and female lens weights increase at the same linear rate. Conclusions: The data support the biphasic growth model for human lenses. Male lenses are significantly larger than female lenses at the conclusion of the prenatal growth mode, but the rate of weight accrual is constant thereafter. Lens weights increase continuously throughout life and can be described with equations that incorporate terms for prenatal and postnatal growth.
MeSH term(s)	Adolescent ; Adult ; Aged ; Aged, 80 and over ; Aging/physiology ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Infant, Newborn ; Lens, Crystalline/anatomy & histology ; Lens, Crystalline/growth & development ; Male ; Middle Aged ; Organ Size ; Tissue Donors
Language	English
Publishing date	2018-12-31
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	2017540-1
ISSN	1090-0535 ; 1090-0535
ISSN (online)	1090-0535
ISSN	1090-0535
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Article ; Online: Lens growth and protein changes in the eastern grey kangaroo.

Augusteyn, Robert C

Molecular vision

2011 Volume 17, Page(s) 3234–3242

Abstract: Purpose: Development in marsupials takes place predominantly ex utero while the young is attached to a nipple in the mother's pouch, very different from that in other species. This study was undertaken to examine whether this affects lens growth and the ...

Abstract	Purpose: Development in marsupials takes place predominantly ex utero while the young is attached to a nipple in the mother's pouch, very different from that in other species. This study was undertaken to examine whether this affects lens growth and the production of lens proteins in kangaroos. Methods: Fresh lenses were obtained at official culls from eastern gray kangaroos (Macropus giganteus). Wet weights were recorded for all and protein contents were determined for one lens from each animal. Dry weights, after fixation were obtained for 20 lenses. Ages were determined using both molar progression and total lens protein content. Lenses were divided into concentric layers by controlled dissolution using phosphate buffered saline. Samples were taken for determination of protein contents and dry weights, which were then used to determine the age of the layer removed. Soluble crystallin distributions were determined by fractionation of the centrifuged extracts using HPLC-GPC and the polypeptide contents of both soluble and insoluble proteins were assessed by SDS-PAGE. Results: Lens growth is continuous from birth throughout adulthood and the increases in wet weight and fixed dry weight can be described with a single logistic growth functions for the whole life span. Three major crystallin classes, α-, β-, and γ-crystallins, were identified in the immature pouch-young animals aged around 60 days after birth. Adult lenses contain, in addition, the taxon-specific μ-crystallin. The proportions of these vary with the age of the lens tissue due to age related insolubilization as well as changes in the synthesis patterns. During early lactation (birth to 190 days), the α-, β-, and γ-crystallins represent 25, 53, and 20% of the total protein, respectively. After the pouch-young first releases the nipple (190 days), there is a rapid decrease in the production of γ-crystallins to around 5% of the total and a corresponding increase in μ-crystallin, from 0.5% to 15%. These changes were complete by the time the animal was fully weaned, around 1.5 years, and the final proportions of the 4 protein classes were maintained for the rest of life. The solubilities of α- and β-crystallins in the center of the lens decreased after age 5 years. Conclusions: Kangaroo lens growth is asymptotic, similar to that in most other species, even though most development of the young animal takes place ex utero. Changes in the patterns of lens protein synthesis in the kangaroo are similar to those observed in other species except for the large decrease in γ-crystallin and the matching increase in the marsupial-specific μ-crystallin, during late lactation.
MeSH term(s)	Age Factors ; Animals ; Chromatography, High Pressure Liquid ; Crystallins/genetics ; Crystallins/metabolism ; Electrophoresis, Polyacrylamide Gel ; Female ; Gene Expression Regulation, Developmental ; Lens, Crystalline/metabolism ; Macropodidae ; Male ; Solubility ; Weights and Measures ; alpha-Crystallins/genetics ; alpha-Crystallins/metabolism ; beta-Crystallins/genetics ; beta-Crystallins/metabolism ; gamma-Crystallins/genetics ; gamma-Crystallins/metabolism
Chemical Substances	Crystallins ; alpha-Crystallins ; beta-Crystallins ; gamma-Crystallins ; crystallin mu (147681-64-9)
Language	English
Publishing date	2011-12-14
Publishing country	United States
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	2017540-1
ISSN	1090-0535 ; 1090-0535
ISSN (online)	1090-0535
ISSN	1090-0535
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Article ; Online: Relationship of the cornea and globe dimensions to the changes in adult human crystalline lens diameter, thickness and power with age.

Mohamed, Ashik / Nandyala, Sushma / Ho, Arthur / Manns, Fabrice / Parel, Jean-Marie A / Augusteyn, Robert C

Experimental eye research

2021 Volume 209, Page(s) 108653

Abstract: It is well known that human crystalline lens shape, dimensions and optical properties change throughout life and influence whole eye refraction. However, it is not clear if lens properties are associated with other ocular parameters. The purpose of the ... ...

Abstract	It is well known that human crystalline lens shape, dimensions and optical properties change throughout life and influence whole eye refraction. However, it is not clear if lens properties are associated with other ocular parameters. The purpose of the present study was to investigate the relationship of corneal and external globe dimensions with adult lens diameter (LD), lens thickness (LT) and lens power (LP) in order to determine if external factors influence lens properties. Postmortem human eyes (n = 66, age = 20-78 years) were obtained from the Ramayamma International Eye Bank, Hyderabad, India. Globe antero-posterior length (GAPL) and mean (average of horizontal and vertical) diameters of cornea (MCD) and globe (MGD) were measured using digital calipers. Eyes were dissected to produce ocular structures that contain the lens maintained in its accommodating framework, including intact zonules, ciliary body and sections of sclera. Specimens were mounted in a mechanical lens stretching system. LD, LT and LP were measured using high magnification retro-illumination photography, slit illumination photography and Scheiner principle-based optical system respectively in the unstretched (accommodated) state. Relationships between external globe and corneal dimensions and LD, LT or LP were assessed by multiple regression analysis. Age (0.012 ± 0.003 mm/year; p<0.001) and GAPL (0.185 ± 0.045 mm/mm; p<0.001) were significant (p<0.0001) predictors of LD. After adjusting for age-related increases, LD appears to be positively correlated with GAPL. Age (0.010 ± 0.004 mm/year; p = 0.009) and GAPL (-0.143 ± 0.060 mm/mm; p = 0.02) were significant (p = 0.001) predictors of LT. After adjusting for the age-related increase, LT appears to be negatively correlated with GAPL. Only age was a significant predictor of LP (-0.26 ± 0.04 D/year; p<0.001). The results suggest that, apart from aging, lens diameter and thickness are dependent on the anteroposterior length of the eye globe. Lens power is not influenced by globe dimensions.
MeSH term(s)	Accommodation, Ocular/physiology ; Adult ; Aged ; Aging/physiology ; Biometry/methods ; Cornea/anatomy & histology ; Cornea/growth & development ; Eye/anatomy & histology ; Eye/growth & development ; Female ; Humans ; Lens, Crystalline/anatomy & histology ; Male ; Middle Aged ; Organ Size ; Refraction, Ocular/physiology ; Young Adult
Language	English
Publishing date	2021-06-05
Publishing country	England
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
ZDB-ID	80122-7
ISSN	1096-0007 ; 0014-4835
ISSN (online)	1096-0007
ISSN	0014-4835
DOI	10.1016/j.exer.2021.108653
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Article ; Online: On the growth and internal structure of the human lens.

Augusteyn, Robert C

Experimental eye research

2010 Volume 90, Issue 6, Page(s) 643–654

Abstract: Growth of the human lens and the development of its internal features are examined using in vivo and in vitro observations on dimensions, weights, cell sizes, protein gradients and other properties. In vitro studies have shown that human lens growth is ... ...

Abstract	Growth of the human lens and the development of its internal features are examined using in vivo and in vitro observations on dimensions, weights, cell sizes, protein gradients and other properties. In vitro studies have shown that human lens growth is biphasic, asymptotic until just after birth and linear for most of postnatal life. This generates two distinct compartments, the prenatal and the postnatal. The prenatal growth mode leads to the formation of an adult nuclear core of fixed dimensions and the postnatal, to an ever-expanding cortex. The nuclear core and the cortex have different properties and can readily be physically separated. Communication and adhesion between the compartments is poor in older lenses. In vivo slit lamp examination reveals several zones of optical discontinuity in the lens. Different nomenclatures have been used to describe these, with the most common recognizing the embryonic, foetal, juvenile and adult nuclei as well as the cortex and outer cortex. Implicit in this nomenclature is the idea that the nuclear zones were generated at defined periods of development and growth. This review examines the relationship between the two compartments observed in vitro and the internal structures revealed by slit lamp photography. Defining the relationship is not as simple as it might seem because of remodeling and cell compaction which take place, mostly in the first 20 years of postnatal life. In addition, different investigators use different nomenclatures when describing the same regions of the lens. From a consideration of the dimensions, the dry mass contents and the protein distributions in the lens and in the various zones, it can be concluded that the juvenile nucleus and the layers contained within it, as well as most of the adult nucleus, were actually produced during prenatal life and the adult nucleus was completed within 3 months after birth, in the final stages of the prenatal growth mode. Further postnatal growth takes place entirely within the cortex. It can also be demonstrated that the in vitro nuclear core corresponds to the combined slit lamp nuclear zones. In view of the information presented in this review, the use of the terms foetal, juvenile and adult nucleus seems inappropriate and should be abandoned.
MeSH term(s)	Body Water ; Crystallins/metabolism ; Humans ; Lens Cortex, Crystalline/cytology ; Lens Cortex, Crystalline/metabolism ; Lens Nucleus, Crystalline/cytology ; Lens Nucleus, Crystalline/embryology ; Lens Nucleus, Crystalline/metabolism ; Organ Size
Chemical Substances	Crystallins
Language	English
Publishing date	2010-02-18
Publishing country	England
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Review
ZDB-ID	80122-7
ISSN	1096-0007 ; 0014-4835
ISSN (online)	1096-0007
ISSN	0014-4835
DOI	10.1016/j.exer.2010.01.013
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Article: Growth of the lens: in vitro observations.

Augusteyn, Robert C

Clinical & experimental optometry

2008 Volume 91, Issue 3, Page(s) 226–239

Abstract: Understanding the normal functioning of the human lens and its role in the development of disorders of vision, such as presbyopia and cataract, requires a thorough knowledge of how the lens grows and how its properties change with age. Many of these ... ...

Abstract	Understanding the normal functioning of the human lens and its role in the development of disorders of vision, such as presbyopia and cataract, requires a thorough knowledge of how the lens grows and how its properties change with age. Many of these properties can be obtained only by studying the isolated organ in vitro. In addition, because of the difficulties in obtaining human tissues, animal lenses are frequently used as models for the human lens. Information is needed for these as well. In this review, current knowledge of lens growth and factors that affect growth are examined in a variety of species. Topics covered include changes in lens weight, dimensions, stiffness and refractive index distribution with age and the influence of other factors such as gender, environment and body size. From these, it has become clear that lens growth is not greatly affected by external influences. Although there are many similarities in the growth of lenses from different species, humans (and probably all primates) have distinctly different growth patterns, with prenatal and postnatal growth having different regulatory mechanisms. As a result, human lens properties are different from those of other species. Unfortunately, many of the published data are unreliable, presumably because of post-mortem changes, making it difficult to extrapolate in vitro observations to the in vivo situation.
MeSH term(s)	Aging/physiology ; Biomechanical Phenomena ; Embryonic Development ; Fetus/anatomy & histology ; Humans ; In Vitro Techniques ; Lens, Crystalline/anatomy & histology ; Lens, Crystalline/embryology ; Lens, Crystalline/growth & development ; Models, Biological ; Organ Size ; Presbyopia/physiopathology ; Risk Factors
Language	English
Publishing date	2008-05
Publishing country	Australia
Document type	Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Review
ZDB-ID	639275-1
ISSN	0816-4622
ISSN	0816-4622
DOI	10.1111/j.1444-0938.2008.00255.x
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Article ; Online: On the relationship between rabbit age and lens dry weight: improved determination of the age of rabbits in the wild.

Augusteyn, Robert C

Molecular vision

2007 Volume 13, Page(s) 2030–2034

Abstract: ... fixed for at least four weeks and the fixed lenses be dried for two weeks at 85 degrees C or, preferably ... three days at 100 degrees C. Any formula, relating age and lens dry weight for any species, must take ...

Abstract	Purpose: Eye lens dry weights are commonly used for estimating the age of animals in the wild, but reported relationships are variable. The purpose of this study was to determine why different relationships have been reported using data available for the same species of rabbits. Methods: Published results that relate lens weight to age for wild European rabbits from four locations in Australia and cottontail rabbits from two locations in the United States have been reexamined. In addition, the effects of variations in lens preparation have been tested with fresh eyes. Results: It was found that, in previous studies, the logistic type relationship between lens weight and age was interpreted inappropriately through the use of age constants, which imply that lens growth commences before conception. Using gestational time as the constant yields a single formula for each species, and this is consistent with most of the published data. Variations in fixation and drying conditions may be responsible for small differences between different populations. Conclusions: When using lens dry weights as a measure of age, it is recommended that eyes be fixed for at least four weeks and the fixed lenses be dried for two weeks at 85 degrees C or, preferably, three days at 100 degrees C. Any formula, relating age and lens dry weight for any species, must take into account the fact that lens growth commences during gestation not before or after.
MeSH term(s)	Aging/physiology ; Animals ; Animals, Newborn/growth & development ; Animals, Wild/anatomy & histology ; Animals, Wild/embryology ; Animals, Wild/growth & development ; Artifacts ; Embryonic Development ; Gestational Age ; Histological Techniques ; In Vitro Techniques ; Lens, Crystalline/anatomy & histology ; Lens, Crystalline/embryology ; Lens, Crystalline/growth & development ; Organ Size ; Rabbits/anatomy & histology ; Rabbits/embryology ; Rabbits/growth & development
Language	English
Publishing date	2007-10-25
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2017540-1
ISSN	1090-0535 ; 1090-0535
ISSN (online)	1090-0535
ISSN	1090-0535
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