Abstract
Abstract: :
Purpose:To examine the human Lamina Cribrosa (LC) in normally hydrated sections from individuals from two separate age groups to reveal its true size, shape and configuration and any age–related changes in these features using Differential Interference Contrast (DIC) optics. METHODS: 22 cadaver eyes (6 pairs), 10 from female and 12 from male donors were used. All eyes fell into one of two age categories, 38–49yrs and 78–89yrs. The optic nerve head was isolated and sectioned in the horizontal plane from each specimen. The LC was viewed using DIC optics under x10 magnification. Measurements of LC thickness were taken and morphological differences were noted. Statistical analyses involved the use of univariate and one–way ANOVA and post hoc testing. Results: The average LC thickness was 0.59mm (+/–0.16). LC thickness was significantly increased in individuals aged 78–89yrs (0.64mm +/–0.09) when compared to those aged 38–49yrs (0.52mm +/–0.17) p value <0.001, univariate ANOVA. A gender difference was observed, males had a significantly thicker LC than females, (0.66mm +/–0.16 and 0.52mm +/–0.13 respectively) p value <0.001, univariate ANOVA. Age differences in lamellar organisation were also noted. Conclusions: The lamina cribrosa (LC) is found in the intraocular portion of the optic nerve, it is a sieve like structure consisting of collagenous lamellae. It allows retinal ganglion cell axons to exit the eye and acts as a barrier between the intra and extraocular spaces. The age related changes of the human LC in the hydrated state have yet to be assessed. Our results indicate an age–related increase in thickness of the LC. We also noted morphological differences in lamellar thickness and organisation between the different age groups. Males were found to have a significantly thicker LC compared to females irrespective of age. These findings are compatible with results from analyses of the extracellular matrix of the LC that have highlighted an age related increase in its major constituents, in particular collagen and elastin. These changes alter the compliance of the LC and this may have implications with respect to susceptibility of the aged population to glaucomatous optic neuropathy.
Keywords: lamina cribrosa • aging • imaging/image analysis: non-clinical