Factors Associated with Lamina Cribrosa Displacement After Trabeculectomy Measured by Optical Coherence Tomography in Advanced Primary Open Angle Glaucoma
Purpose: To investigate the relationship of lamina cribrosa displacement to corneal biomechanical properties and visual function after mitomycin C-augmented trabeculectomy. Method: Eighty-one primary open angle eyes were imaged before and after trabeculectomy using an enhanced depth spectral-domain optical coherence tomography (SDOCT). Corneal biomechanical properties were measured with the Ocular Response Analyser before the surgery. The anterior lamina cribrosa (LC) was marked at several
... ked at several points in each of six radial scans to evaluate LC displacement in response to Intraocular pressure (IOP) reduction. A Humphrey visual field test (HVF) was performed before the surgery as well as three and six months postoperatively. Results: Factors associated with a deeper baseline anterior lamina cribrosa depth (ALD) were cup-disc ratio (P=0.04), baseline IOP (P= 0.01), corneal hysteresis (P= 0.001), and corneal resistance factor (P= 0.001). After the surgery, the position of LC became more anterior (negative), posterior (positive) or remained unchanged. The mean LC displacement was -42 μm (P= 0.001) and was positively correlated with the magnitude of IOP reduction (regression coefficient: 0.251, P=0.02), and negatively correlated with age (regression coefficient: - 0.224, P= 0.04) as well as baseline cup-disk ratio (Regression coefficient: -0.212,P= 0.05) Eyes with a larger negative LC displacement were more likely to experience an HVF improvement of more than 3 dB gain in mean deviation (P= 0.002). Conclusion: A lower SDOCT cup-disc ratio, younger age, and a larger IOP reduction were correlated with a larger negative LC displacement and improving HVF. Corneal biomechanics did not predict LC displacement.