Asymmetric Macular Structural Damage Is Associated With Relative Afferent Pupillary Defects in Patients With Glaucoma

Detection of Relative Afferent Pupillary Defect and Its Correlation with Structural and Functional Asymmetry in Patients with Glaucoma Using Hitomiru, a Novel Hand-Held Pupillometer

Patients with asymmetric glaucomatous optic neuropathy (GON) present a relative afferent pupillary defect (RAPD) in the eye with more advanced damage. Although useful, pupillometric RAPD quantification is not widely used as it is not portable. Whether asymmetry of the peripapillary capillary perfusion density (CPD) detected using optical coherence tomography angiography correlates with the severity of RAPD remains unknown. This study assessed RAPD in 81 patients with GON using Hitomiru, a novel hand-held infrared binocular pupillometer. The correlation and ability to detect clinical RAPD based on the swinging flash light test of two independent RAPD parameters (the maximum pupil constriction ratio and the constriction maintenance capacity ratio) were assessed. The coefficient of determination (R²) was calculated between each of the two RAPD parameters and asymmetry of the circumpapillary retinal nerve fiber layer thickness (cpRNFLT), ganglion cell layer/inner plexiform layer thickness (GCL/IPLT), and CPD. The two RAPD parameters showed a correlation coefficient of 0.86 and areas under the receiver operating characteristic (ROC) curve of 0.85-0.88, with R² being 0.63-0.67 for the visual field, 0.35-0.45 for cpRNFLT, 0.45-0.49 for GCL/IPLT, and 0.53-0.59 for CPD asymmetry. Hitomiru has high discriminatory performance in detecting RAPD in patients with asymmetric GON. CPD asymmetry may better correlate with RAPD than cpRNFLT and GCL/IPLT asymmetry.

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.

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

Purpose:

The relative afferent pupillary defect (RAPD) is an important sign of asymmetrical retinal ganglion cell damage. The purpose of this study was to quantify RAPD by a pupillometer (RAPiDo, Neuroptics) and assess its correlation with asymmetric glaucoma and manual pupillary assessment.

Methods:

A total of 173 subjects were enrolled in the study and categorized into glaucoma, n = 130, and control, n = 43. Subjects were all recruited in the Glaucoma Clinic of the Aravind Eye Hospital in Madurai during their follow-up. They were 18 years and older, with best corrected visual acuity of 6/36 or better. Exclusion criteria included all retinal pathologies, optic atrophies, ocular injuries, severe uveitis, cloudy corneas, dense cataracts, or use of mydriatics or miotic drugs. RAPD was assessed in all subjects using an automated pupillometer and the results were compared with the swinging flash light test conducted on the same subjects by an experienced ophthalmologist. We looked at the correlation between RAPD and the intereye difference in cup-to-disc ratio (CDR), mean deviation (MD) of visual field testing, and retinal nerve fiber layer (RNFL) thickness. Sensitivity and specificity were assessed by area under the receiver operator characteristic (AUROC) analysis.

Results:

Glaucoma patients had significant RAPD (0.55 ± 0.05 log units) when compared with the controls (0.25 ± 0.05 log units), P < 0.001. Significant intereye differences in CDR, MD, and RNFL between glaucoma and control (P < 0.001) were seen. There was a good correlation between the magnitude and sign of RAPD and these intereye differences in CDR (r = 0.52, P < 0.001), MD (r = 0.44, P < 0.001) and RNFL thickness (r = 0.59, P < 0.001). When compared with the experienced ophthalmologist, AUROC was 0.94, with 89% sensitivity and 91.7% specificity.

Conclusion:

The good correlation between the magnitude of RAPD, as measured by the automated pupillometer, and intereye differences in MD, CDR, and RNFL thickness in glaucomatous, and the good sensitivity and specificity when compared with the experienced ophthalmologist, suggest that pupillometry may be useful as a screening tool to assess asymmetric glaucoma.

Lateral thinking - Interocular symmetry and asymmetry in neurovascular patterning, in health and disease

No biological system or structure is likely to be perfectly symmetrical, or have identical right and left forms. This review explores the evidence for eye and visual pathway asymmetry, in health and in disease, and attempts to provide guidance for those studying the structure and function of the visual system, where recognition of symmetry or asymmetry may be essential. The principal question with regards to asymmetry is not 'are the eyes the same?', for some degree of asymmetry is pervasive, but 'when are they importantly different?'. Knowing if right and left eyes are 'importantly different' could have significant consequences for deciding whether right or left eyes are included in an analysis or for examining the association between a phenotype and ocular parameter. The presence of significant asymmetry would also have important implications for the design of normative databases of retinal and optic nerve metrics. In this review, we highlight not only the universal presence of asymmetry, but provide evidence that some elements of the visual system are inherently more asymmetric than others, pointing to the need for improved normative data to explain sources of asymmetry and their impact on determining associations with genetic, environmental or health-related factors and ultimately in clinical practice.