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.

PurposeWe tested the hypotheses that retinal venule diameter (Dv) is associated with baseline intracranial pressure (ICP) level and that Dv is reduced shortly after ICP lowering.MethodsDv and arteriole diameter (Da) were extracted from scanning laser ophthalmoscopic images in 40 eyes of 20 adult human subjects (10 with and 10 without papilledema) immediately before and after measurement of ICP (range, 10–55 cm H2O) and ICP lowering by cerebrospinal fluid (CSF) drainage via lumbar puncture (LP). Generalized estimating equations (GEE) modeled the relationship between baseline ICP, Da and Dv before LP. Additional GEE modeled the relationship between initial ICP and change in Da and Dv (post-LP – pre-LP) following ICP lowering.ResultsTest–retest variability of diameter measurements ranged from 0.1 to 2.9 μm (0.1%–2.72%). Neither Da nor Dv pre-LP was associated with baseline ICP level (P = 0.140 Dv, P = 0.914 Da, GEE). Da and Dv change after ICP lowering was associated with baseline ICP, with vessel diameters increasing with lower baseline ICP and decreasing with elevated initial ICP (P = 0.030 baseline ICP vs. Dv change, P = 0.012 baseline ICP vs. Da change, GEE models).ConclusionsRetina arteriole and venule diameters change immediately following ICP lowering. The direction of change is dependent on the initial ICP; both increased in subjects with high ICP and both decreased in subjects with normal ICP.Translational RelevanceThe relationship between initial ICP and direction of retinal vessel size change following ICP lowering suggests a potential effect of ICP on cerebral and ocular hemodynamics that is relevant when considering the use of retinal vessel measurements as a clinical marker of ICP change.

Significant additional long-term IOP lowering may be achieved by switching to bimatoprost in patients with open-angle glaucoma who are not at target IOP with latanoprost.

Background. Diabetic retinopathy and kidney disease share underlying mechanisms of microvascular damage and are often comorbid in people with diabetes. We evaluated whether there is a relationship between retinal capillary perfusion as measured by swept-source optical coherence tomography angiography and estimated glomerular filtration rate (eGFR) and albuminuria in patients with diabetes and chronic kidney disease (CKD). Method. A cross-sectional pilot study was conducted at the University of Washington among a subset of participants with diabetes and CKD participating in a larger cohort study. Participants were excluded if they were known to have kidney disease from conditions other than diabetes. Ten participants (11 eyes) were included. Retinal nonperfusion (RNP) and vessel density (VD) were measured by swept-source optical coherence tomography angiography in 30° and 60° field of view (FOV) regions centered at the fovea. Correlations of RNP and VD with eGFR and albuminuria were analyzed. Results. Participants had a mean age of 72 years, hemoglobin A1c of 8.1%, eGFR of 45 mL/min/1.73 m2, and urine albumin-to-creatinine ratio of 162 mg/g. Mean (SD) RNP was 6.6% (4.2%) and 16.9% (7.7%) in 30° and 60° FOV regions, respectively. eGFR was negatively correlated to RNP in both the 30° and 60° FOV regions (R = −0.69, p = 0.004 , and R = −0.46, p = 0.057 , respectively), and correlations were stronger among a subset of 7 participants with evidence of diabetic retinopathy on exam and fundus photos. The estimated GFR was not significantly correlated with vessel density. Urine albumin-to-creatinine ratio was not significantly correlated with RNP or VD. Conclusions. Our proof-of-concept study showed that lower eGFR was significantly correlated with retinal nonperfusion in participants with diabetes and CKD. Advanced retinal imaging may enhance the noninvasive evaluation of kidney function in diabetes.