Corneal hysteresis in patients with glaucoma-like optic discs, ocular hypertension and glaucoma.

BACKGROUND: To compare corneal hysteresis (CH) measurements between patients with glaucoma, ocular hypertension (OHT) and glaucoma-like optic discs (GLD)- defined as a cup to disc ratio greater than or equal to 0.6 with normal intraocular pressure (IOP) and visual fields. The secondary aim was to investigate whether corneal resistance factor (CRF) and central corneal thickness (CCT) differ between patient groups. METHODS: In this cross sectional study a total of 123 patients (one eye each) were recruited from a glaucoma outpatient department to undergo ocular response analyser (ORA) testing and ultrasound pachymetry as well as clinical examination. A One-way Analysis of Covariance (ANCOVA) was conducted to evaluate the mean difference in CH between the three diagnostic groups (glaucoma, OHT and GLD) correcting for potential confounding factors, IOP and age. Analysis was repeated for CRF and CCT. RESULTS: There was a significant difference in mean CH across the three diagnosis groups; F(2, 115) = 96.95; p < 0.001. Mean CH significantly higher for GLD compared to glaucoma (mean difference 1.83, p < 0.001), and significantly higher for OHT compared to glaucoma (mean difference 2.35, p < 0.001). Mean CH was slightly lower in patients with GLD than those with OHT but this difference was not statistically significant. A similar pattern was seen when the analysis was repeated for CRF and CCT. CONCLUSIONS: Higher CH in GLD and OHT compared to glaucoma suggests increased viscoelasticity of ocular tissues may have a protective role against glaucoma.

What's in a Gene? Pseudoexfoliation Syndrome and Pigment Dispersion Syndrome in the Same Patient.

Pseudoexfoliation syndrome (PXS) and pigment dispersion syndrome (PDS) are two of the commonest disorders to produce secondary open-angle glaucoma through trabecular meshwork blockage. Each is a defined clinical entity, and while genetics likely play a significant role in the pathogenesis of both, the specific genes involved appear to be distinct. There is surprisingly little published in the literature regarding the coexistence of PDS and PXS in the same patient. We present the intriguing case of a patient who developed PDS in one eye and PXS in the other. This unusual case acts as a platform for an interesting discussion of the genomics of PXS and PDS.

The Function of Matricellular Proteins in the Lamina Cribrosa and Trabecular Meshwork in Glaucoma.

PURPOSE: To review the current literature regarding the role of matricellular proteins in glaucoma, specifically in the lamina cribrosa (LC) region of the optic nerve head (ONH) and the trabecular meshwork (TM). METHODS: A literature search was performed for published articles describing the expression and function of matricellular proteins such as thrombospondin (TSP), connective tissue growth factor (CTGF), secreted protein acidic and rich in cysteine (SPARC), and periostin in glaucoma. RESULTS: In glaucoma, there are characteristic extracellular matrix (ECM) changes associated with optic disc cupping in the ONH and subsequent visual field defects. Matricellular proteins are a family of nonstructural secreted glycoproteins, which enable cells to communicate with their surrounding ECM, including CTGF, also known as CCN2, TSPs, SPARC, periostin, osteonectin, and tenascin-C and -X, and other ECM proteins. Such proteins appear to play a role in fibrosis and increased ECM deposition. Importantly, most are widely expressed in tissues particularly in the TM and ONH, and deficiency of TSP1 and SPARC has been shown to lower intraocular pressure in mouse models of glaucoma through enhanced outflow facility. CONCLUSION: This article highlights the role of matricellular proteins in glaucoma pathology. The potential role of these proteins in glaucoma is emerging as some have an association with the pathophysiology of the TM and LC region and might therefore be potential targets for therapeutic intervention in glaucoma.