Abstract
Based on biomechanical theory, lamina cribrosa (LC) displacement, the key component of progressive glaucomatous change, is presumed to be dependent on intraocular pressure (IOP) as well as tissue stiffness of LC. In the performance of the Valsalva maneuver, both IOP and cerebrospinal fluid pressure can increase. The present study investigated the age-dependent variation of LC displacement during the standardized Valsalva maneuver in healthy subjects. Sixty-three (63) eyes (age range: 20–76 years) were prospectively underwent IOP measurement and Cirrus HD-OCT optic disc scans before and during the standardized Valsalva maneuver. During the standardized Valsalva maneuver, the IOP significantly increased from 13.2 ± 2.9 mmHg to 18.6 ± 5.2 mmHg (P < 0.001). The maximal LC depth significantly decreased in the younger age groups (age: 20 s to 40 s) but not in the older age groups (age: over 50). The BMO distance did not change significantly. Younger age (P = 0.009), a smaller increase of IOP during the Valsalva maneuver (P = 0.002), and greater baseline maximal LC depth (P = 0.013) were associated with more anterior displacement of the LC during the standardized Valsalva maneuver. Taken together, age as well as translaminar pressure dynamics seems to play a crucial role in LC biomechanics.
Highlights
Having hypothesized that age-related change of the lamina cribrosa (LC) and peripapillary sclera influences the degree of LC displacement during the standardized Valsalva maneuver, we investigated, in the present study, whether LC depth change during the standardized Valsalva maneuver differed according to subject age and evaluated the factors associated with LC displacement
Five subjects were excluded due to unclear visibility of the anterior LC surface, and two others owing to difficulties in performing the standardized Valsalva maneuver
Zhang et al.[25] recently investigated intraocular pressure (IOP) and CSFP changes during the Valsalva challenge in patients with lumbar puncture. They reported that the CSFP increment (10.5 ± 2.7 mmHg) exceeded that of IOP (1.9 ± 2.4 mmHg), with the consequence that the TLPD was decreased or reversed
Summary
Despite controversies to linkage between CSFP and glaucoma development, the position of LC, representatively measured as LC depth, can be dependent on translaminar pressure dynamics[22]. This phenomenon has been further evidenced by posterior displacement of the LC in pediatric patients with surgical decompression due to increased intracranial pressure[23]. Recent study with numerical simulated model exhibited less remarkable influence of CSFP than IOP on ONH biomechanics, and proposed different role of IOP and CSFP on ONH deformation[24] In this regard, further investigation and better understanding for LC behavior according to the translaminar pressure dynamics is imperative. Having hypothesized that age-related change of the LC and peripapillary sclera influences the degree of LC displacement during the standardized Valsalva maneuver, we investigated, in the present study, whether LC depth change during the standardized Valsalva maneuver differed according to subject age and evaluated the factors associated with LC displacement
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