Quantification of RAPD by an automated pupillometer in asymmetric glaucoma and its correlation with manual pupillary assessment

Diagnostic Value of Point-of-Care Ultrasound-Guided Assessment of Relative Afferent Pupillary Defect in Adult Ocular Trauma Patients Presenting to the Emergency Department: A Prospective Cohort Study

OBJECTIVES

Early diagnosis of relative afferent pupillary defects (RAPDs) in patients with ocular trauma is crucial for timely management and improved outcomes. However, clinical examination can be challenging for patients with periorbital ecchymosis. This study aimed to compare the diagnostic accuracy of point-of-care ultrasound (POCUS) and clinical examination by emergency physicians for detecting RAPD in adult ocular trauma patients and to evaluate the proportion of RAPD in patients with ocular trauma who presented to the ED.

METHODS

This prospective cohort study was conducted at an academic emergency department in South India. Adult ocular trauma patients were assessed for RAPD using clinical examinations by emergency physicians and POCUS. The diagnostic accuracies of both methods were compared, with the ophthalmologist's final diagnosis serving as the gold standard. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for both techniques.

RESULTS

A total of 376 patients (median age, 35 years) were included in this study. RAPD was identified in 14.63% of the patients. The sensitivity and specificity of POCUS in detecting RAPD were 92.73% and 99.38%, respectively, which were higher than those of clinical examination, with a sensitivity of 81.82% and specificity of 99.07%. The PPV and NPV of the clinical examination were 93.75% and 96.95%, respectively, whereas the PPV and NPV of POCUS were 96.23% and 98.76%, respectively. POCUS accurately diagnosed RAPD in patients with periorbital ecchymosis.

CONCLUSION

POCUS-guided RAPD assessment proves to be a better diagnostic adjunct compared to clinical examination in patients with ocular trauma presenting to the emergency department.

Binocular head-mounted chromatic pupillometry can detect structural and functional loss in glaucoma

Aim

The aim of this study is to evaluate the utility of binocular chromatic pupillometry in detecting impaired pupillary light response (PLR) in patients with primary open-angle glaucoma (POAG) and to assess the feasibility of using binocular chromatic pupillometer in opportunistic POAG diagnosis in community-based or telemedicine-based services.

Methods

In this prospective, cross-sectional study, 74 patients with POAG and 23 healthy controls were enrolled. All participants underwent comprehensive ophthalmologic examinations including optical coherence tomography (OCT) and standard automated perimetry (SAP). The PLR tests included sequential tests of full-field chromatic stimuli weighted by rods, intrinsically photosensitive retinal ganglion cells (ipRGCs), and cones (Experiment 1), as well as alternating chromatic light flash-induced relative afferent pupillary defect (RAPD) test (Experiment 2). In Experiment 1, the constricting amplitude, velocity, and time to maximum constriction/dilation were calculated in three cell type-weighted responses, and the post-illumination response of ipRGC-weighted response was evaluated. In Experiment 2, infrared pupillary asymmetry (IPA) amplitude and anisocoria duration induced by intermittent blue or red light flashes were calculated.

Results

In Experiment 1, the PLR of POAG patients was significantly reduced in all conditions, reflecting the defect in photoreception through rods, cones, and ipRGCs. The variable with the highest area under the receiver operating characteristic curve (AUC) was time to max dilation under ipRGC-weighted stimulus, followed by the constriction amplitude under cone-weighted stimulus and the constriction amplitude response to ipRGC-weighted stimuli. The impaired PLR features were associated with greater visual field loss, thinner retinal nerve fiber layer (RNFL) thickness, and cupping of the optic disk. In Experiment 2, IPA and anisocoria duration induced by intermittent blue or red light flashes were significantly greater in participants with POAG than in controls. IPA and anisocoria duration had good diagnostic value, correlating with the inter-eye asymmetry of visual field loss.

Conclusion

We demonstrate that binocular chromatic pupillometry could potentially serve as an objective clinical tool for opportunistic glaucoma diagnosis in community-based or telemedicine-based services. Binocular chromatic pupillometry allows an accurate, objective, and rapid assessment of retinal structural impairment and functional loss in glaucomatous eyes of different severity levels.

Pupillary response to chromatic light stimuli as a possible biomarker at the early stage of glaucoma: a review

Glaucoma is a multifactorial neurodegenerative disease of the optic nerve currently considered a severe health problem because of its high prevalence, being the primary cause of irreversible blindness worldwide. The most common type corresponds to Primary Open-Angle Glaucoma. Glaucoma produces, among other alterations, a progressive loss of retinal ganglion cells (RGC) and its axons which are the key contributors to generate action potentials that reach the visual cortex to create the visual image. Glaucoma is characterized by Visual Field loss whose main feature is to be painless and therefore makes early detection difficult, causing a late diagnosis and a delayed treatment indication that slows down its progression. Intrinsically photosensitive retinal ganglion cells, which represent a subgroup of RGCs are characterized by their response to short-wave light stimulation close to 480 nm, their non-visual function, and their role in the generation of the pupillary reflex. Currently, the sensitivity of clinical examinations correlates to RGC damage; however, the need for an early damage biomarker is still relevant. It is an urgent task to create new diagnostic approaches to detect an early stage of glaucoma in a prompt, quick, and economical manner. We summarize the pathology of glaucoma and its current clinical detection methods, and we suggest evaluating the pupillary response to chromatic light as a potential biomarker of disease, due to its diagnostic benefit and its cost-effectiveness in clinical practice in order to reduce irreversible damage caused by glaucoma.

A differential of the left eye and right eye neurological pupil index is associated with discharge modified Rankin scores in neurologically injured patients

Background

Automated infrared pupillometry (AIP) and the Neurological Pupil index (NPi) provide an objective means of assessing and trending the pupillary light reflex (PLR) across a broad spectrum of neurological diseases. NPi quantifies the PLR and ranges from 0 to 5; in healthy individuals, the NPi of both eyes is expected to be ≥ 3.0 and symmetric. AIP values demonstrate emerging value as a prognostic tool with predictive properties that could allow practitioners to anticipate neurological deterioration and recovery. The presence of an NPi differential (a difference ≥ 0.7 between the left and right eye) is a potential sign of neurological abnormality.

Methods

We explored NPi differential by considering the modified Rankin Score at discharge (DC mRS) among patients admitted to neuroscience intensive care units (NSICU) of 4 U.S. and 1 Japanese hospitals and for two cohorts of brain injuries: stroke (including subarachnoid hemorrhage, intracerebral hemorrhage, acute ischemic stroke, and aneurysm, 1,200 total patients) and 185 traumatic brain injury (TBI) patients for a total of more than 54,000 pupillary measurements.

Results

Stroke patients with at least 1 occurrence of an NPi differential during their NSICU stay have higher DC mRS scores (3.9) compared to those without an NPi differential (2.7; P < .001). Patients with TBI and at least 1 occurrence of an NPi differential during their NSICU stay have higher discharge modified Rankin Scale scores (4.1) compared to those without an NPi differential (2.9; P < .001). When patients experience both abnormalities, abnormal (NPi < 3.0) and an NPi differential, the latter has an anticipatory relationship with respect to the former (P < .001 for z-score skewness analysis). Finally, our analysis confirmed ≥ 0.7 as the optimal cutoff value for the NPi differential (AUC = 0.71, P < .001).

Conclusion

The NPi differential is an important factor that clinicians should consider when managing critically ill neurological injured patients admitted to the neurocritical care units.

Trial registration

NCT02804438, Date of Registration: June 17, 2016.

Correlation between relative afferent pupillary defect and visual field defects on Humphrey automated perimetry: A cross-sectional clinical trial

Purpose

To evaluate the correlations between relative afferent pupillary defect (RAPD) magnitude, assessed using the clinical plus scale and neutral density filters, and visual field parameters in patients with unilateral or asymmetrical bilateral optic neuropathy or retinopathy.

Methods

Fifty-two patients with RAPD, graded by the swinging flashlight test and neutral density filters, were analyzed in this cross-sectional trial. The RAPD clinical plus scale was divided into grade 1+, initial weak constriction; grade 2+, initial stall then dilatation; grade 3+, immediate dilatation; and grade 4+, fixed amaurotic pupil. Patients with positive RAPD underwent a visual field examination with Humphrey automated perimetry that included visual field index (VFI), mean deviation (MD), and pattern standard deviation (PSD). Spearman’s rank correlation coefficients and linear regression were used to analyze the association between RAPD grades and visual field parameters.

Results

RAPD clinical plus grades were correlated with interocular VFI (r = 0.55, P < 0.001) and MD (r = 0.48, P = 0.004) differences. Average interocular VFI differences were estimated as follows: 16.75 × RAPD plus grade– 7.53. RAPD, graded by neutral density filters, was correlated with VFI (r = 0.59, P < 0.001), MD (r = 0.54, P < 0.001), and PSD (r = 0.34, P = 0.01).

Conclusions

The RAPD plus scale and neutral density filter grading systems were associated with quantitative visual field defect parameters, with VFI showing the strongest association. RAPD clinical grading could substitute more sophisticated central visual field evaluation methods as a low-cost, low-tech, and widely available approach.

A haploscope based binocular pupillometer system to quantify the dynamics of direct and consensual Pupillary Light Reflex

This study described the development of a haploscope-based pupillometer for the parametrization of the Pupillary Light Reflex (PLR), and its feasibility in a set of 30 healthy subjects (light or dark-colored irides) and five patients diagnosed with Relative Afferent Pupillary Defect (RAPD). Our supplementary aim focused on evaluating the influence of iris colour on the PLR to decide whether a difference in PLR parameters should be anticipated when this system is used across ethnicities. All the participants underwent a customized pupillometry protocol and the generated pupil traces, captured by an eye tracker, were analyzed using exponential fits to derive PLR parameters. A Pupil Response Symmetry (PRS) coefficient was calculated to predict the presence of RAPD. The mean (SD) Initial PD during dilation (3.2 (0.5) mm) and the minimum PD during constriction (2.9 (0.4) mm) in the light iris group had a statistically significant (p < 0.001) higher magnitude compared to the dark iris group. The normal limits of the PRS coefficient ranged from - 0.20 to + 1.07 and all RAPD patients were outside the calculated normal limits. This proposed system, analysis strategies, and the tested metrics showed good short-term repeatability and the potential in detecting pupil abnormalities in neuro-ophthalmic diseases.

Quantification of relative afferent pupillary defect by an automated pupillometer and its relationship with visual acuity and dimensions of macular lesions in age-related macular degeneration

Purpose

The occurrence of relative afferent pupillary defect (RAPD) secondary to optic nerve diseases and widespread retinal disorders is well established. However, only very few reports of RAPD in macular disorders exist in the literature. In this study, we used automated pupillometer to evaluate RAPD in eyes with macular lesions.

Methods

It was a prospective cross-sectional study. A total of 82 patients with choroidal neovascular membrane (CNVM) - 65 unilateral and 17 bilateral macular lesions - were enrolled. RAPD was assessed with an automated pupillometer and macular lesions evaluated with optical coherence tomography (OCT). The length of the ellipsoid zone disruption was measured as the longest length of lesion on the horizontal raster scans and the area of macular lesion was measured manually, mapping the affected area of ellipsoid zone on the enface images.

Results

: RAPD scores showed good correlation with the intereye difference in length of maximum ellipsoid zone disruption (r-value = 0.84, P value <0.001) and macular lesion area as measured on OCT in all unilateral cases (r-value = 0.84, P value <0.001). Best-corrected visual acuity was also found to have a significant correlation with lesion size on the OCT as well as the length of ellipsoid zone disruption in unilateral cases.

Conclusion

: RAPD evaluated with an automated binocular pupillometer is a noninvasive and objective method to assess macular lesions in CNVMs; it shows good correlation with structural lesion dimensions on OCT in unilateral cases. Further longitudinal studies are needed to assess the significance of these findings in disease progression as well as correlation with lesion response to treatment.

Pupillary light reflex as a diagnostic aid from computational viewpoint: A systematic literature review

This work presents a detailed and complete review of publications on pupillary light reflex (PLR) used to aid diagnoses. These are computational techniques used in the evaluation of pupillometry, as well as their application in computer-aided diagnoses (CAD) of pathologies or physiological conditions that can be studied by observing the movements of miosis and mydriasis of the human pupil. A careful survey was carried out of all studies published over the last 10 years which investigated, electronic devices, recording protocols, image treatment, computational algorithms and the pathologies related to PLR. We present the frontier of existing knowledge regarding methods and techniques used in this field of knowledge, which has been expanding due to the possibility of performing diagnoses with high precision, at a low cost and with a non-invasive method.

Evaluating State-of-the-Art Computerized Pupillary Assessments for Glaucoma Detection: A Systematic Review and Meta-Analysis

Computerized pupillary light reflex assessment devices (CPLRADs) may serve as an effective screening tool for glaucomatous optic neuropathy, since they can dynamically detect abnormal pupillary responses from a novel sequence of light stimuli and functionally-shaped stimuli. The aim of this study was to systematically evaluate the current state of advanced CPLRADs and accuracy of application in detecting glaucoma. An electronic literature search of PubMed, MEDLINE, and Embase from database inception to December 2019 was performed. Studies that reported data on the use of computer-aided pupillometry with monocular and/or binocular monitoring in glaucoma patients were included. Two review authors independently conducted the study selection and extracted study data. A total of twenty-five studies were included in this review; eight studies with a total of 829 subjects were included in this meta-analysis. Data were pooled using a random-effect model, since the significant heterogeneity (P < 0.1, I ²> 50%). Our meta-analysis of eight studies showed reasonably high summary sensitivity and specificity estimates of 0.81 (95% CI 0.73-0.89) and 0.83 (95% CI: 0.75-0.91), respectively. Simpler monochromatic devices, such as Pupilmetrix^TM PLR60, generally performed as well as or slightly better than more complex chromatic devices. This review suggests that CPLRADs may facilitate direct clinical decision making for glaucoma diagnosis and evaluation, and may provide a deeper understanding of the pathomechanism of glaucoma.