Thickness of the Lamina Cribrosa, and the Anatomic Relationships Between the Lamina Cribrosa and the Cerebrospinal Fluid and Intraocular Spaces in Glaucomatous and Non-Glaucomatous Eyes

Abstract

Purpose: : The optic disc provides a separation between the intraocular space (IOS) and the cerebrospinal fluid space (CSFS). The main structure for this division is the lamina cribrosa (LC). A possible role of the pressure in the CSFS in glaucomatous optic neuropathy has been recently proposed¹. The purpose of this study was to analyze and compare the thickness of the LC, and the anatomic correlations between the LC and the IOS and the CSFS in glaucomatous and non-glaucomatous eyes².

Methods: : A total of 25 human eyes were analyzed: 17 globes were from enucleated eyes with choroidal melanoma without optic nerve involvement (control group), and 8 eyes from painful intractable glaucoma in blind eyes (glaucoma group). Axial (horizontal) histologic sections passing through the optic nerve and the pupil were digitized and morphometrically analyzed. The following parameters were measured: the length of the anterior and posterior surfaces of the LC (and its ratio); the thickness of the LC at the center of the disc, both borders, and the halfway points between center and borders; the length of the posterior border of the LC exposed to the pia; the shortest distance between the inner surface of the LC and the CSFS and the shortest distance between the inner surface of the LC and the pia matter. Statistical analysis was performed using the unpaired t test and were considered significant when p < 0.05.

Results: : The ratio of the anterior surface to the posterior surface of the LC was lower in the control group compared to glaucoma (p < 0.01). The LC was thinner in the glaucoma group when compared with controls in the 5 measured points (p < 0.0001). The posterior surface of the LC in contact with the CSFS was wider (p < 0.05), and the shortest distance between LC and the pia matter was significantly shorter (p < 0.05) in the glaucoma group.

Conclusions: : The LC is significantly thinner in glaucomatous eyes. Glaucomatous eyes had a wider contact area between the posterior surface of the LC and the CSFS. These results may play an influential role in the pathophysiology of optic disc damage in glaucoma.

References: : 1-Berdahl JP, et al. Ophthalmology 2008;115:763-768. 2- Jonas JB, et al. Invest Ophthalmol Vis Sci 2003;44:5189-5195.

Keywords: optic disc • anatomy • pathology: human