@article{kaskar_wells-gray_fleischman_grace_2022, title={Evaluating machine learning classifiers for glaucoma referral decision support in primary care settings}, volume={12}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-022-12270-w}, abstractNote={Several artificial intelligence algorithms have been proposed to help diagnose glaucoma by analyzing the functional and/or structural changes in the eye. These algorithms require carefully curated datasets with access to ocular images. In the current study, we have modeled and evaluated classifiers to predict self-reported glaucoma using a single, easily obtained ocular feature (intraocular pressure (IOP)) and non-ocular features (age, gender, race, body mass index, systolic and diastolic blood pressure, and comorbidities). The classifiers were trained on publicly available data of 3015 subjects without a glaucoma diagnosis at the time of enrollment. 337 subjects subsequently self-reported a glaucoma diagnosis in a span of 1-12 years after enrollment. The classifiers were evaluated on the ability to identify these subjects by only using their features recorded at the time of enrollment. Support vector machine, logistic regression, and adaptive boosting performed similarly on the dataset with F1 scores of 0.31, 0.30, and 0.28, respectively. Logistic regression had the highest sensitivity at 60% with a specificity of 69%. Predictive classifiers using primarily non-ocular features have the potential to be used for identifying suspected glaucoma in non-eye care settings, including primary care. Further research into finding additional features that improve the performance of predictive classifiers is warranted.}, number={1}, journal={SCIENTIFIC REPORTS}, author={Kaskar, Omkar G. and Wells-Gray, Elaine and Fleischman, David and Grace, Landon}, year={2022}, month={May} }
 @article{fleischman_kaskar_shams_zhang_olson_zdanski_thorp_kuznetsov_grace_lee_2019, title={A Novel Porcine Model for the Study of Cerebrospinal Fluid Dynamics: Development and Preliminary Results}, volume={10}, ISSN={["1664-2295"]}, DOI={10.3389/fneur.2019.01137}, abstractNote={Idiopathic intracranial hypertension, space-flight associated neuro-ocular syndrome (SANS), and glaucoma are conditions that are among a spectrum of cerebrospinal fluid (CSF)-related ophthalmologic disease. This implies that local CSF pressures at the level of the optic nerve are involved to variable extent in these disease processes. However, CSF pressure measurements are problematic due to invasiveness and interpretation. The pressure measured by a lumbar puncture is likely not the same as the orbital CSF pressure. It is believed this is at least in part due to the flow restrictive properties of the optic canal. To investigate CSF flow within the orbit, a model for CSF dynamics was created using three medium-sized pigs. Contrast was administered through a lumbar subarachnoid space access. The contrast front was imaged with repeated computed tomographic (CT) imaging. Once contrast entered the orbit, rapid, sequential CT imaging was performed until the contrast reached the posterior globe. Head tilting was performed to highlight the role of gravitational dependence within the subarachnoid space.}, journal={FRONTIERS IN NEUROLOGY}, author={Fleischman, David and Kaskar, Omkar and Shams, Rayad and Zhang, Xinxin and Olson, Daniel and Zdanski, Carlton and Thorp, Brian D. and Kuznetsov, Andrey V and Grace, Landon and Lee, Yueh Z.}, year={2019}, month={Oct} }
 @article{kaskar_fleischman_lee_thorp_kuznetsov_grace_2019, title={Identifying the Critical Factors Governing Translaminar Pressure Differential Through a Compartmental Model}, volume={60}, ISSN={["1552-5783"]}, DOI={10.1167/iovs.18-26200}, abstractNote={Purpose The effective management of glaucoma is hindered by an incomplete understanding of its pathologic mechanism. While important, intraocular pressure (IOP) alone is inadequate in explaining glaucoma. Non-IOP–mediated risk factors such as cerebrospinal fluid (CSF) pressure have been reported to contribute to glaucomatous optic neuropathy. Due to the difficulty associated with experimental measurement of the salient variables, such as the retrobulbar CSF pressure, porosity of the subarachnoid space (SAS), and especially those concerned with the perioptic SAS, there remains a limited understanding of the CSF behavior contributing to the translaminar pressure gradient (TLPG), hypothesized to be a critical factor in the development of glaucoma. Method An integrated compartmental model describing the intracranial and orbital CSF dynamics, coupled with intraocular dynamics, is developed based on first principles of fluid mechanics. A sensitivity analysis is performed to identify anatomic characteristics that significantly affect the retrobulbar subarachnoid space (RSAS) pressure and, consequently, the TLPG. Results Of the 28 parameters considered, the RSAS pressure is most sensitive to CSF flow resistance in the optic nerve SAS and the potential lymphatic outflow from the optic nerve SAS into the orbital space. A parametric study demonstrates that a combination of resistance in the range of 1.600 × 1012 − 1.930 × 1012 Pa s/m3 (200.0 − 241.3 mm Hg min/mL) with 5% to 10% lymphatic CSF outflow yields RSAS pressures that are consistent with the limited number of studies in the literature. Conclusions The results suggest that a small percentage of lymphatic CSF outflow through the optic nerve SAS is likely. In addition, flow resistance in the orbital CSF space, hypothesized to be a function of patient-specific optic nerve SAS architecture and optic canal geometry, is a critical parameter in regulating the RSAS pressure and TLPG.}, number={8}, journal={INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE}, author={Kaskar, Omkar G. and Fleischman, David and Lee, Yueh Z. and Thorp, Brian D. and Kuznetsov, Andrey V. and Grace, Landon}, year={2019}, month={Jul}, pages={3204–3214} }
 @article{morales_kaskar_grace_2018, title={Design and processing of an elastomeric nanocomposite for biomedical pressure sensing applications}, volume={17}, ISSN={["2352-4928"]}, DOI={10.1016/j.mtcomm.2018.09.019}, abstractNote={Taguchi Method is used to identify parameter effects and interactions to inform the design and processing of a carbon black (CB) and poly(styrene-isobutylene-styrene) (SIBS) nanocomposite. Potential uses include stick-to-skin pressure sensors and other applications for which targeted mechanical properties and pressure sensitivity derived from the tailorability of SIBS/CB are required. Specimens ranging from 10% to 20% CB content by weight were fabricated by high-shear mixing, ultrasonication, and solvent casting. The relationship between pressure-sensing capability and tensile strength of SIBS/CB nanocomposites is complex and dependent upon nanoparticle dispersion (represented by high-shear mixing time), CB content, and casting temperature. By using an L8 3-Factor 2-Level Taguchi orthogonal array and screening analysis, design and processing parameters to achieve targeted mechanical and electrical performance of SIBS/CB nanocomposites can be determined through a relatively small number of experiments. Main effects and interactions of the processing parameters were identified. Analysis indicates that mechanical strength is highly dependent on CB content and dispersion (mixing time), whereas pressure-dependent electrical resistance is highly dependent on CB content and casting temperature. The predictive models derived from these efforts will enable preliminary design of processing parameters for SIBS/CB nanocomposites to targeted, application-specific mechanical and pressure-sensing properties.}, journal={MATERIALS TODAY COMMUNICATIONS}, author={Morales, Brigitte and Kaskar, Omkar and Grace, Landon R.}, year={2018}, month={Dec}, pages={278–288} }