The Driving Simulator Visual Field in Glaucoma – A Novel Task to Test Available Field of View

Glaucoma causes peripheral vision loss and impaired driving performance. We developed a novel driving simulator visual field task (DSVF) in a panoramic driving simulator to map the available field of view under different perceptual task loads in naturalistic settings. Our hypothesis is that “available field of view” will decrease with increasing task load in both glaucoma subjects and controls. This is a cross-sectional study with 28 glaucoma subjects and 19 controls. DSVF (60̊ x 20̊ visual field at 2.5 m) was tested in a high-fidelity interactive driving simulator in 4 different scenarios: a) no distractions b) no driving condition with unrestricted head/eye movements c) driving d) driving with PASAT (Paced Auditory Serial Addition Test). Each test was repeated twice. The main outcome measure was a visual field index (DSVF-VFI). DSVF-VFI was compared to the Humphrey Visual field -HVF-VFI monocularly and binocularly to validate the test. The DSVF task was highly reproducible and comparable to HVF. An A-pillar scotoma appeared in all DSVF trials. In both glaucoma subjects and controls, the DSVF-VFI decreased with increasing task load. The DSVFI decreased significantly more in the glaucoma group as compared to the control group. We developed a predictive formula to predict available field of view while driving from clinic based HVF. Glaucoma subjects were impaired in completing multiple task demands, such as driving and DSVF- either because a) compensation for peripheral vision loss acts as a continuously present load on attention capacity b) glaucoma is associated with diminished cognitive capacity as compared to controls

Relative Contributions of Intracranial Pressure and Intraocular Pressure on Lamina Cribrosa Behavior

Purpose. To characterize the relative contributions of intraocular pressure (IOP) and intracranial pressure (ICP) on lamina cribrosa (LC) behavior, specifically LC depth (LCD) and LC peak strain. Methods. An axially symmetric finite element model of the posterior eye was constructed with an elongated optic nerve and retro-orbital subarachnoid space ensheathed by pia and dura mater. -e mechanical environment in LC was evaluated with ICP ranging from 5 to 15mmHg and IOP from 10 to 45 mmHg. LCD and LC peak strains at various ICP and IOP levels were estimated using full factorial experiments. Multiple linear regression analyses were then applied to estimate LCD and LC peak strain using ICP and IOP as independent variables. Results. Both increased ICP and decreased IOP led to a smaller LCD and LC peak strain. -e regression correlation coefficient for LCD was −1.047 for ICP and 1.049 for IOP, and the ratio of the two regression coefficients was −1.0. -e regression correlation coefficient for LC peak strain was −0.025 for ICP and 0.106 for IOP, and the ratio of the two regression coefficients was −0.24. A stiffer sclera increased LCD but decreased LC peak strain; besides, it increased the relative contribution of ICP on the LCD but decreased that on the LC peak strain. Conclusions. ICP and IOP have opposing effects on LCD and LC peak strain. While their effects on LCD are equivalent, the effect of IOP on LC peak strain is 3 times larger than that of ICP. -e influences of these pressure are dependent on sclera material properties, which might explain the pathogenesis of ocular hypertension and normal-tension glaucoma

Relative Contributions of Intracranial Pressure and Intraocular Pressure on Lamina Cribrosa Behavior

Purpose. To characterize the relative contributions of intraocular pressure (IOP) and intracranial pressure (ICP) on lamina cribrosa (LC) behavior, specifically LC depth (LCD) and LC peak strain. Methods. An axially symmetric finite element model of the posterior eye was constructed with an elongated optic nerve and retro-orbital subarachnoid space ensheathed by pia and dura mater. -e mechanical environment in LC was evaluated with ICP ranging from 5 to 15mmHg and IOP from 10 to 45 mmHg. LCD and LC peak strains at various ICP and IOP levels were estimated using full factorial experiments. Multiple linear regression analyses were then applied to estimate LCD and LC peak strain using ICP and IOP as independent variables. Results. Both increased ICP and decreased IOP led to a smaller LCD and LC peak strain. -e regression correlation coefficient for LCD was −1.047 for ICP and 1.049 for IOP, and the ratio of the two regression coefficients was −1.0. -e regression correlation coefficient for LC peak strain was −0.025 for ICP and 0.106 for IOP, and the ratio of the two regression coefficients was −0.24. A stiffer sclera increased LCD but decreased LC peak strain; besides, it increased the relative contribution of ICP on the LCD but decreased that on the LC peak strain. Conclusions. ICP and IOP have opposing effects on LCD and LC peak strain. While their effects on LCD are equivalent, the effect of IOP on LC peak strain is 3 times larger than that of ICP. -e influences of these pressure are dependent on sclera material properties, which might explain the pathogenesis of ocular hypertension and normal-tension glaucoma

Three-dimensional shape analysis of peripapillary retinal pigment epithelium-basement membrane layer based on OCT radial images

The peripapillary retinal pigment epithelium-basement membrane (ppRPE/BM) layer angle was recently proposed as a potential index for estimating intracranial pressure noninvasively. However, the ppRPE/BM layer angle, measured from the optical coherence tomography (OCT) scans, varied across the radial directions of the optic disc. This made the ppRPE/BM layer angle difficult to be utilized in its full potential. In this study, we developed a mathematical model to quantify the ppRPE/BM layer angles across radial scans in relation to the ppRPE/BM 3D morphology in terms of its 3D angle and scanning tilt angles. Results showed that the variations of the ppRPE/BM layer angle across radial scans were well explained by its 3D angle and scanning tilt angles. The ppRPE/BM layer 3D angle was reversely fitted from the measured ppRPE/BM layer angles across radial directions with application to six eyes from four patients, who underwent medically necessary lumbar puncture. The fitted curve from our mathematical model matched well with the experimental measurements (R2 \u3e 0.9 in most cases). This further validated our mathematical model. The proposed model in this study has elucidated the variations of ppRPE/BM layer angle across 2D radial scans from the perspective of the ppRPE/BM layer 3D morphology. It is expected that the ppRPE/BM layer 3D angle developed in this study could be further exploited as a new biomarker for the optic disc

INFLUENCE OF INTRACRANIAL PRESSURE ON THE LAMINA CRIBROSA

ABSTRACT Glaucoma is an eye disease related with vision field loss. Although previous study has investigated the influence of intraocular pressure (IOP) on the glaucoma damage to the lamina cribrosa (LC), the intracranial pressure's (ICP) effect on the LC has never been elucidated. The goal of this work is to determine the effect of ICP on the LC

Episcleral Venous Pressure And Intraocular Pressure As Biomarkers For Intracranial Pressure Changes

There is need for non-invasive reliable intracranial pressure (ICP) monitoring. We hypothesize that ICP changes will affect ocular venous drainage and consequently affect the episcleral venous pressure (EVP), intraocular pressure (IOP) and retinal vein diameter (RVD) of the eye. EVP measurement is routine in aqueous humor dynamics glaucoma research. EVP has a predicted 1:1 correlation with IOP

Piloting A New Method For Estimating Visual Field Loss In A Panoramic Naturalistic Environment

Patients with field defects have increased motor vehicle accidents. Standard automated perimetry lacks external validity in naturalistic environments. To resolve this, Driving Simulator Visual Field(DSVF) was designed in a high-fidelity driving simulation system with 290° panoramic environment

The Ability to Fake a Neurologic Field Defect

To determine if volunteers can simulate and reproduce three automated visual field (Humphrey) (HVF) defects hemianopia (HA), quadrantanopia (QA) and central scotoma (CS)

Optic Nerve Head Morphology In Perinatal Onset Static Encephalopathy.

To evaluate optic nerve head(ONH) pallor and cupping in children with perinatal onset static encephalopathy(POSE) and its association with age of onset, type of cerebral palsy(CP), ambulation and neuro-radiologic abnormalities.SKcerebralpals