Analysis of nuclear fiber cell compaction in transparent and cataractous diabetic human lenses by scanning electron microscopy

BACKGROUND: Compaction of human ocular lens fiber cells as a function of both aging and cataractogenesis has been demonstrated previously using scanning electron microscopy. The purpose of this investigation is to quantify morphological differences in the inner nuclear regions of cataractous and non-cataractous human lenses from individuals with diabetes. The hypothesis is that, even in the presence of the osmotic stress caused by diabetes, compaction rather than swelling occurs in the nucleus of diabetic lenses. METHODS: Transparent and nuclear cataractous lenses from diabetic patients were examined by scanning electron microscopy (SEM). Measurements of the fetal nuclear (FN) elliptical angles (anterior and posterior), embryonic nuclear (EN) anterior-posterior (A-P) axial thickness, and the number of EN fiber cell membrane folds over 20 μm were compared. RESULTS: Diabetic lenses with nuclear cataract exhibited smaller FN elliptical angles, smaller EN axial thicknesses, and larger numbers of EN compaction folds than their non-cataractous diabetic counterparts. CONCLUSION: As in non-diabetic lenses, the inner nuclei of cataractous lenses from diabetics were significantly more compacted than those of non-cataractous diabetics. Little difference between diabetic and non-diabetic compaction levels was found, suggesting that diabetes does not affect the degree of compaction. However, consistent with previous proposals, diabetes does appear to accelerate the formation of cataracts that are similar to age-related nuclear cataracts in non-diabetics. We conclude that as scattering increases in the diabetic lens with cataract formation, fiber cell compaction is significant

Analysis of nuclear fiber cell compaction in transparent and cataractous diabetic human lenses by scanning electron microscopy

BACKGROUND: Compaction of human ocular lens fiber cells as a function of both aging and cataractogenesis has been demonstrated previously using scanning electron microscopy. The purpose of this investigation is to quantify morphological differences in the inner nuclear regions of cataractous and non-cataractous human lenses from individuals with diabetes. The hypothesis is that, even in the presence of the osmotic stress caused by diabetes, compaction rather than swelling occurs in the nucleus of diabetic lenses. METHODS: Transparent and nuclear cataractous lenses from diabetic patients were examined by scanning electron microscopy (SEM). Measurements of the fetal nuclear (FN) elliptical angles (anterior and posterior), embryonic nuclear (EN) anterior-posterior (A-P) axial thickness, and the number of EN fiber cell membrane folds over 20 μm were compared. RESULTS: Diabetic lenses with nuclear cataract exhibited smaller FN elliptical angles, smaller EN axial thicknesses, and larger numbers of EN compaction folds than their non-cataractous diabetic counterparts. CONCLUSION: As in non-diabetic lenses, the inner nuclei of cataractous lenses from diabetics were significantly more compacted than those of non-cataractous diabetics. Little difference between diabetic and non-diabetic compaction levels was found, suggesting that diabetes does not affect the degree of compaction. However, consistent with previous proposals, diabetes does appear to accelerate the formation of cataracts that are similar to age-related nuclear cataracts in non-diabetics. We conclude that as scattering increases in the diabetic lens with cataract formation, fiber cell compaction is significant

Morphology of the normal human lens

Purpose. To provide a quantitative, morphologic description of differentiated lens fiber cells in all regions of aged normal human lenses. Methods. Transparent normal human lenses (age range, 44 to 71 years) were examined with correlative transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Vibratome sections allowed examination of internal structures, whereas dissected whole lenses revealed surface characteristics. Additionally, image analysis was used to measure cross-sectional areas of fiber cells. Results. Approximate regional dimensions (percentage of diameter and thickness, respectively) were determined for whole lenses : cortex 16%, 17% ; adult nucleus 24%, 21% ; juvenile nucleus 12%, 9% ; fetal nucleus 45%, 49% ; and embryonic nucleus 3%, 4%. Cortical cells were irregularly hexagonal, and the average cross-sectional area measured 24 ± 9 μm2. Adult nuclear cells were flattened with intricate membranous interdigitations and an area of 7 ± 2 μm2. Juvenile nuclear cells had an area of 14 ± 5 μm2. Fetal nuclear cells were rounded with an area of 35 ± 22 μm2. Embryonic nuclear cells also were rounded and had a variable area of 80 ± 68 μm2. Fiber cell cytoplasm in all lens regions appeared smooth in texture and homogeneous in staining density. Conclusions. Both TEM and SEM are necessary to obtain a complete description of fiber cells. Cross-sections of fibers give new insights into the lamellar organization of the lens, indicating that each region has characteristic cell shapes and sizes. Furthermore, average dimensions were used to demonstrate that the number of cells and approximate growth rates vary significantly between adjacent regions

Representative scanning electron micrographs of split rabbit lens nuclei

<p><b>Copyright information:</b></p><p>Taken from "Age-related compaction of lens fibers affects the structure and optical properties of rabbit lenses"</p><p>http://www.biomedcentral.com/1471-2415/7/19</p><p>BMC Ophthalmology 2007;7():19-19.</p><p>Published online 20 Dec 2007</p><p>PMCID:PMC2249566.</p><p></p> A-B. Low and medium magnification of adult rabbit lens nuclei. C-D. Low and medium magnification of aged rabbit lens nuclei. It is clear that the EN of aged lenses appeared more disorganized than the EN of adult lenses (compare panels B and D)

Representative light micrographs from thick (1–2 μm) sections of cross-sectioned cortical fiber cells

<p><b>Copyright information:</b></p><p>Taken from "Age-related compaction of lens fibers affects the structure and optical properties of rabbit lenses"</p><p>http://www.biomedcentral.com/1471-2415/7/19</p><p>BMC Ophthalmology 2007;7():19-19.</p><p>Published online 20 Dec 2007</p><p>PMCID:PMC2249566.</p><p></p> A. Adult lens at 7 mm equatorial diameter. B. Adult lens at 6 mm equatorial diameter. C. Aged lens at 7 mm equatorial diameter. D. Aged lens at 6 mm equatorial diameter. Cross sectioned fibers from aged rabbit lenses were noticeably and significantly smaller than those from adult rabbit lenses