Study on association of the central cornea histology change with age in adults by in vivo confocal microscopy / 眼科研究

ABSTRACT

Background Corneal confocal microscopy can denamically offer the morphological image of corneal cells at cellular level.To find out the dynamic change of corneal thickness and morphology of corneal cells with aging is very important for the design of corneal refractive surgery.ObjectivePresent study is to find out the important relevance of dynamic change of corneal thickness and morphology of corneal cells with aging and the design of corneal refractive surgery and investigate the influence of age on central corneal tissue and characterize precisely the anatomy of cornea by in vivo confocal microscopy.Methods122 eyes of 122 normal subjects were enrolled in this study with the age from 18 through 80 years old.The subjects were diagnosed as emmetropia in the Center of Tianjin Medical University from August 2003 to December 2007.All eyes were examined in vivo by confocal microscopy.The cell morphology,cell density and corneal thickness were measured by confocal microscopy.The relationship of central corneal tissue change and age was evaluated.ResultsThe density of corneal superficial basement epithelial cells showed a significantly negative correlation with age (r=-0.355,P=0.017).The keratocyte density in the anterior and posterior stroma indicated a significantly negative correlation with age (r_1=-0.462,P=0.001;r_2=-0.403,P=0.016).The thickness of corneal epithelium cells had a significantly negative correlation with age (P=0.02).The mean value of total corneal thickness and stromal thickness in high myopic eyes was (523.2±26.20)μm and (468.4±20.72)μm respectively,presenting a significantly negative correlation with age (r_1=-0.552,P=0.014;r_2=-0.545,P=0.035).A significantly negative correlation was also found in endothelial cell areas and density with age (r_1=0.417,P=0.004;r_2=-0.598,P=0.002).The percentage of polymorphological corneal endothelial cells was considerably increased(r=0.417,P=0.004)but that of pleomorphism cells was significantly decreased in >60-year-old population compared with younger subjects (r=-0.598,P=0.002).The morphology of corneal basement cell,anterior stroma cytocyte and endothelial cell were normal in younger subjects,and enlargement of the cells in size,decreases of number and density of the cells were found in >60-year-old subject.ConclusionThe anatomy and histology of the central cornea in young subjects exist discrepancy from older ones.The corneal hisological changes with aging include thinner thickness of epithelium,thinner thickness of cornea,decreased density of keratocyte and endothelial cells and increased size of endothelial cells.Corneal thickness is asymmetric and seems to undergo age-related anatomic changes.