Aging effect on rabbit's lens fibers; A scanning electron microscopic study

The eye lens is a minute organ with complex structure that plays an indispensible role in the process of vision. It is composed mainly of modified epithelial cells that form a unique type of fibers. This study was performed to highlight the morphological variations of lens fibers in different age groups in rabbits' lenses. These variations in fibers' structure may have a great impact on the optical properties of the lens. Material and methods: Fifteen white male rabbits of different ages ranging from one month to four and half years were equally divided into three groups; young, adult and aged. Their lenses were dissected and processed for scanning electron microscopy. Gross lenses' diameters and A-P axis lengths were assessed using digitalized gross photomicrographs from dissecting microscope. Also, diameter of lens fibers was measured digitally for comparative purposes among the groups. Statistical analysis for significance of obtained data was performed using analysis of variance and student-T test. Results: The average equatorial diameter was 6.1% and 14.5% larger in adult and aged lenses than young ones. The average A-P axis length was 14.1% in adult and 21.7% in aged lenses more than in young lenses as well. Lens fibers exhibited some variations in the pattern of lateral interdigitations that became more branched with folding. Fiber diameter demonstrated an increase from young to adult lenses then a decrease in aged lens was noticed. Conclusion: Lens fibers undergo some morphological variations by age progression in the form of compaction in addition to changes in the appearance of ball and socket interdigitations. These changes can be correlated to some age-related optical disturbances as senile prespyopia and cataract. Recommendation: Age-related changes in the morphology of lens fibers should be considered in any experimental study including the lens to avoid interpretation bias and get more reliable results