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Keegan Harkins, Sachin Kedar, Yasir Jamal Sepah, Mohammad Ali Sadiq, Justin West, Deepta Ghate; Lamina Cribrosa Position Changes with the Valsalva maneuver. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):5550.
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© ARVO (1962-2015); The Authors (2016-present)
The Valsalva maneuver (VM) causes an increase in intraocular pressure (IOP) and intracerebral pressure (ICP). This prospective clinical study aimed to test if acute changes in ICP and IOP can cause changes in the lamina cribrosa (LC) position.
The study population had 20 healthy volunteers from the University of Kentucky. VM was performed with a manometer and a mouth pressure of 30-33 cm of H2O held for 15 seconds. The Icare® tonometer was used to check IOP before and during the VM (after 15 seconds). The Spectralis OCT® was used to acquire 12 radial optic nerve head images before and during the VM (after 15 seconds). There was a 10 minutes gap between right and left eye measurements and between the IOP and OCT acquisition. 3 of the 12 radial OCT sections (selected by expert grader) were independently graded by 2 graders for anterior lamina cribrosa depth (LCD), Bruch’s membrane opening width (BMO) and cup depth from BMO plane. Any image with a measurement discrepancy>40 µm was re-graded by the expert grader.
The mean age was 29±4.7 years with 40 eyes analyzed There was no significant change in BMO depth (mean change -3.7±37.5 µm), cup depth (mean change -1.3±24.1 µm) and LC depth (mean change -0.3±31.4 µm) with the VM. IOP increased with the VM in all eyes (mean change3.2±2.2 mmHg, p<0.05). 20 eyes had anterior LC shift with the VM (mean LC position change -20.9±13.6 µm). 14 eyes had LC posterior shift (mean LC position change -29.2±28.2 µm). 2 eyes had no change in LC position and 4 eyes had ungradable LC. Mean IOP change was significantly (p<0.05) higher with anterior LC shift (3.65 mm Hg) versus posterior LC shift (2.93 mm Hg). There was no significant difference in IOP change with BMO widening versus shortening and in anterior and posterior cup depth shift. There was no significant association between BMO widening or shortening and anterior or posterior LC shift. There was a significant association between anterior and posterior shift of the LC and cup depth (chi square=4.37, p< 0.05).
Despite an IOP rise in all eyes, the VM causes anterior LC shift in 50% of eyes. This anterior LC shift is associated with higher IOP change and an anterior shift of the cup depth but not with BMO width changes. The eyes with anterior LC shift presumably had a rise in ICP> IOP which would presume that the LC position changes with fluctuations in ICP.
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