Quantitative Association Between Peripapillary Bruch's Membrane Shape and Intracranial Pressure

Abstract

PurposeThe purpose of this study was to determine if there is a quantitative relationship between chronic intracranial pressure (ICP) and peripapillary Bruch's membrane (pp-BM) shape and to determine whether change in pp-BM shape can be detected within 1 hour after ICP lowering by lumbar puncture (LP).MethodsIn this study, 30° nasal-temporal optical coherence tomography B-scans were obtained within 1 hour before and after LP in 39 eyes from 20 patients (age = 23–86 years, 75% female, ICP [opening pressure] = 10–55 cm H2O). A total of 16 semi-landmarks defined pp-BM on each image. Geometric morphometric analysis identified principal components of shape in the image set. Generalized estimating equation models, accounting for within-subject correlation, were used to identify principal components that were associated with chronic ICP (comparing pre-LP images between eyes) and/or acute ICP changes (comparing pre- and post-LP images within eyes). The pp-BM width and anterior pp-BM location were calculated directly from each image and were studied in the same manner.ResultsPrincipal component 1 scalar variable on pre-LP images was associated with ICP (P < 0.0005). Principal component 4 magnitude changed within eyes after LP (P = 0.003). For both principal components 1 and 4, lower ICP corresponded with a more posterior position of pp-BM. Chronic ICP was associated with both pp-BM width (6.81 μm/cm H2O; P = 0.002) and more anterior location of temporal and nasal pp-BM margins (3.41, 3.49 μm/cm H2O; P < 0.0005, 0.002).ConclusionsThis study demonstrates a quantitative association between pp-BM shape and chronic ICP level. Changes in pp-BM shape are detectable within 1 hour of lowering ICP. pp-BM shape may be a useful marker for chronic ICP level and acute ICP changes. Further study is needed to determine how pp-BM shape changes relate to clinical markers of papilledema.

Current concepts of cerebrospinal fluid dynamics and the translaminar cribrosa pressure gradient: a paradigm of optic disk disease

“…197 Gampa and colleagues analyzed 20 patients undergoing LP and found a detectable downward bowing of the Bruch membrane complex within 1 hour of lowering the ICP, supporting the concept that it is a flexible and dynamic structure that acutely changes with alterations in CSF pressure. 54 Anand and coworkers also found a decrease in the Bruch membrane complex angulation immediately after LP in 5 patients with IIH. 2 In addition to the Bruch membrane complex orientation, there are structural changes in the LC in response to changes in CSF pressure.…”

Update on the Diagnosis and Treatment of Idiopathic Intracranial Hypertension

“…70 Research studies have demonstrated that quantitative OCT parameters of the optic nerve head such as optic nerve head volume and eye shape relate to other optic nerve head measures and CSF pressure. 71,72 Furthermore, OCT measures of optic nerve swelling normalized in association with treatment provided in the IIHTT 73 ; however, these are not considered established diagnostic tests as yet.…”

Three-Dimensional Characterization of Peripapillary Retinal Pigment Epithelium-Basement Membrane Layer in Patients following Lumbar Puncture

“…Morphological quantifications from the OCT scans (e.g., retinal thickness and lamina cribrosa depth) facilitate the diagnosis and treatment planning of many blinding diseases [5][6][7][8]. The shape of peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer has attracted much attention due to its relationship with ICP fluctuations [9]. Specifically, Sibony et al used a manual segmentation method for selected patients with symmetrical temporal-nasal scans, and observed that the ppRPE/BM layer exhibited a deeper V-shape following the ICP-lowering intervention [10].…”

“…There are several limitations to the methods used by these groups. The principal component analysis (PCA) method was generally used in the aforementioned shape analysis [9,11]. However, the principal components depend on the choice of dataset [12,13], and the shape analysis results highly depend on the choice of OCT scan direction.…”

“…However, the principal components depend on the choice of dataset [12,13], and the shape analysis results highly depend on the choice of OCT scan direction. Moreover, only one OCT scan per patient was used for the ppRPE/BM layer shape analysis (mostly the temporal-nasal scan) [9][10][11]14] due to the labor intensive methods for manual segmentations. However, one recent study showed that the ppRPE/BM layer shapes were different across various radial directions [15].…”