Esotropia, nystagmus and optic disk staphyloma in Donnai-Barrow syndrome / Esotropia, nistagmo e estafiloma de disco óptico na síndrome de Donnai-Barrow

ABSTRACT A 12-year-old boy with Donnai-Barrow syndrome diagnosed intra-uterus presented esotropia, high myopia, nystagmus, and optic disk staphyloma in an ophthalmologic examination. The patient had associated Fanconi syndrome and sensorineural hearing loss as well as facial manifestations as hypertelorism, downward slanting of palpebral fissures and low ear implantation. Magnetic resonance imaging revealed agenesis of the corpus callosum. To our knowledge, this is the first reported case associated with esotropia, nystagmus, and optic disk staphyloma.

RESUMO Paciente do sexo masculino, 12 anos, com diagnóstico intrauterino de síndrome de Donnai-Barrow, apresentava ao exame oftalmológico esotropia, alta miopia, nistagmo e estafiloma de disco óptico. Associado ao quadro, apresentava síndrome de Falconi e perda auditiva neurossensorial, além de alterações faciais, como hipertelorismo, inclinação inferior das fissuras palpebrais e implantação baixa das orelhas. Ressonância magnética revelou agenesia de corpo caloso. Ao nosso conhecimento, este é o primeiro caso relatado associando esotropia, nistagmo e estafiloma de disco óptico.

Remyelination in humans due to a retinoid-X receptor agonist is age-dependent.

Remyelination efficiency declines with advancing age in animal models, but this has been harder to demonstrate in people with multiple sclerosis. We show that bexarotene, a putatively remyelinating retinoid-X receptor agonist, shortened the visual evoked potential latency in patients with chronic optic neuropathy aged under 42 years only (with the effect diminishing by 0.45 ms per year of age); and increased the magnetization transfer ratio of deep gray matter lesions in those under 43 years only. Addressing this age-related decline in human remyelination capacity will be an important step in the development of remyelinating therapies that work across the lifespan.

Methanol-induced optic neuropathy: a still-present problem.

Methanol-induced optic neuropathy (Me-ION) is a serious condition that may result in long-term or irreversible visual impairment or even blindness secondary to damage and loss of function of the optic nerve and retina. Me-ION shows a tendency to occur as mass poisonings around the world with a clear predilection for poor societies in developing countries. The main mechanism underlying the molecular basis of Me-ION is the inhibition of the mitochondrial oxidative phosphorylation process through the binding of the toxic metabolite of methanol-formic acid-with the key enzyme of this process-cytochrome c oxidase. However, other mechanisms, including damage to the eye tissues by oxidative stress causing the intensification of the oxidative peroxidation process with the formation of cytotoxic compounds, as well as an increase in the synthesis of pro-inflammatory cytokines and influence on the expression of key proteins responsible for maintaining cell homeostasis, also play an important role in the pathogenesis of Me-ION. Histopathological changes in the eye tissues are mainly manifested as the degeneration of axons and glial cells of the optic nerve, often with accompanying damage of the retina that may involve all its layers. Despite the development of therapeutic approaches, persistent visual sequelae are seen in 30-40% of survivors. Thus, Me-ION continues to be an important problem for healthcare systems worldwide.

Multimodal Machine Learning Using Visual Fields and Peripapillary Circular OCT Scans in Detection of Glaucomatous Optic Neuropathy.

PURPOSE: To develop and validate a multimodal artificial intelligence algorithm, FusionNet, using the pattern deviation probability plots from visual field (VF) reports and circular peripapillary OCT scans to detect glaucomatous optic neuropathy (GON). DESIGN: Cross-sectional study. SUBJECTS: Two thousand four hundred sixty-three pairs of VF and OCT images from 1083 patients. METHODS: FusionNet based on bimodal input of VF and OCT paired data was developed to detect GON. Visual field data were collected using the Humphrey Field Analyzer (HFA). OCT images were collected from 3 types of devices (DRI-OCT, Cirrus OCT, and Spectralis). Two thousand four hundred sixty-three pairs of VF and OCT images were divided into 4 datasets: 1567 for training (HFA and DRI-OCT), 441 for primary validation (HFA and DRI-OCT), 255 for the internal test (HFA and Cirrus OCT), and 200 for the external test set (HFA and Spectralis). GON was defined as retinal nerve fiber layer thinning with corresponding VF defects. MAIN OUTCOME MEASURES: Diagnostic performance of FusionNet compared with that of VFNet (with VF data as input) and OCTNet (with OCT data as input). RESULTS: FusionNet achieved an area under the receiver operating characteristic curve (AUC) of 0.950 (0.931-0.968) and outperformed VFNet (AUC, 0.868 [95% confidence interval (CI), 0.834-0.902]), OCTNet (AUC, 0.809 [95% CI, 0.768-0.850]), and 2 glaucoma specialists (glaucoma specialist 1: AUC, 0.882 [95% CI, 0.847-0.917]; glaucoma specialist 2: AUC, 0.883 [95% CI, 0.849-0.918]) in the primary validation set. In the internal and external test sets, the performances of FusionNet were also superior to VFNet and OCTNet (FusionNet vs VFNet vs OCTNet: internal test set 0.917 vs 0.854 vs 0.811; external test set 0.873 vs 0.772 vs 0.785). No significant difference was found between the 2 glaucoma specialists and FusionNet in the internal and external test sets, except for glaucoma specialist 2 (AUC, 0.858 [95% CI, 0.805-0.912]) in the internal test set. CONCLUSIONS: FusionNet, developed using paired VF and OCT data, demonstrated superior performance to both VFNet and OCTNet in detecting GON, suggesting that multimodal machine learning models are valuable in detecting GON.

Spacetime in the brain: rapid brain network reorganization in visual processing and recovery.

Functional connectivity networks (FCN) are the physiological basis of brain synchronization to integrating neural activity. They are not rigid but can reorganize under pathological conditions or during mental or behavioral states. However, because mental acts can be very fast, like the blink of an eye, we now used the visual system as a model to explore rapid FCN reorganization and its functional impact in normal, abnormal and post treatment vision. EEG-recordings were time-locked to visual stimulus presentation; graph analysis of neurophysiological oscillations were used to characterize millisecond FCN dynamics in healthy subjects and in patients with optic nerve damage before and after neuromodulation with alternating currents stimulation and were correlated with visual performance. We showed that rapid and transient FCN synchronization patterns in humans can evolve and dissolve in millisecond speed during visual processing. This rapid FCN reorganization is functionally relevant because disruption and recovery after treatment in optic nerve patients correlated with impaired and recovered visual performance, respectively. Because FCN hub and node interactions can evolve and dissolve in millisecond speed to manage spatial and temporal neural synchronization during visual processing and recovery, we propose "Brain Spacetime" as a fundamental principle of the human mind not only in visual cognition but also in vision restoration.

The Relationship Between Optic Disc and Retinal Artery Position and Glaucomatous Visual Field Progression.

Purpose: To investigate whether retinal structural parameters, including positions of the optic disc and major retinal arteries, affect glaucomatous progression of the visual field (VF). Methods: In this cohort study, 116 eyes of 73 patients with primary open angle glaucoma (POAG) were included. VFs were measured using the Humphrey Field Analyzer 24-2 program and the VF was divided into seven sectors according to the corresponding optic disc angle. Average total deviation (TD) was calculated in each sector. Positions of major retinal arteries in the superotemporal and inferotemporal areas were decided by identifying the points where the retinal artery intersected the 3.4-mm-diameter circle around the optic disc. The relationship between sectorial TD VF progression rate and eight variables (age, mean and standard deviation of intraocular pressure during the observation period, baseline sectorial TD value, papillomacular bundle tilt angle, and axial length, along with superior/inferior arterial angle) was investigated. Results: The main outcome measures were the association between retinal structural parameters and glaucomatous progression of VF. The superior retinal artery angular position was positively associated with sectorial TD progression rates in two central sectors in the inferior hemifield, which suggests faster VF progression where superior retinal artery angles are narrow. Papillomacular bundle tilt was not associated with TD progression rate in any sector. Conclusions: Progression of the inferior VF was associated with the superior retinal artery angular position in this study of POAG.

Strain by virtual extensometers and video-imaging optical coherence tomography as a repeatable metric for IOP-Induced optic nerve head deformations.

PURPOSE: To determine if in vivo strain response of the Optic Nerve Head (ONH) to IOP elevation visualized using Optical Coherence Tomography (OCT) video imaging and quantified using novel virtual extensometers was able to be provided repeatable measurements of tissue specific deformations. METHODS: The ONHs of 5 eyes from 5 non-human primates (NHPs) were imaged by Spectralis OCT. A vertical and a horizontal B-scan of the ONH were continuously recorded for 60 s at 6 Hz (video imaging mode) during IOP elevation from 10 to 30 mmHg. Imaging was repeated over three imaging sessions. The 2D normal strain was computed by template-matching digital image correlation using virtual extensometers. ANOVA F-test (F) was used to compare inter-eye, inter-session, and inter-tissue variability for the prelaminar, Bruch's membrane opening (BMO), lamina cribrosa (LC) and choroidal regions (against variance the error term). F-test of the ratio between inter-eye to inter-session variability was used to test for strain repeatability across imaging sessions (FIS). RESULTS: Variability of strain across imaging session (F = 0.7263, p = 0.4855) and scan orientation was not significant (F = 1.053, p = 0.3066). Inter session variability of strain was significantly lower than inter-eye variability (FIS = 22.63, p = 0.0428) and inter-tissue variability (FIS = 99.33 p = 0.00998). After IOP elevation, strain was highest in the choroid (-18.11%, p < 0.001), followed by prelaminar tissue (-11.0%, p < 0.001), LC (-3.79%, p < 0.001), and relative change in BMO diameter (-0.57%, p = 0.704). CONCLUSIONS: Virtual extensometers applied to video-OCT were sensitive to the eye-specific and tissue-specific mechanical response of the ONH to IOP and were repeatable across imaging sessions.

Altered spontaneous brain activity patterns in dysthyroid optic neuropathy: a resting-state fMRI study.

This research investigates the characteristics of spontaneous brain activity in dysthyroid optic neuropathy patients using the regional homogeneity technique. Sixteen patients with dysthyroid optic neuropathy and 16 thyroid-associated ophthalmopathy patients without dysthyroid optic neuropathy were recruited, matched for weight, height, age, sex, and educational level. All participants underwent resting-state functional nuclear resonance imaging, and the characteristics of spontaneous brain activity were evaluated using the regional homogeneity technique. Each participant in the dysthyroid optic neuropathy group also completed the Hospital Anxiety and Depression scale. Receiver operating characteristic curves were used to compare brain activity between the two groups. Pearson correlation analysis evaluated the relationship between regional homogeneity and clinical manifestations in dysthyroid optic neuropathy patients. In addition, we analyzed the correlation between Hospital Anxiety and Depression scale and regional homogeneity. We found that the regional homogeneity values at the corpus callosum/cingulate gyrus and parietal lobe/middle frontal gyrus significantly decreased in dysthyroid optic neuropathy patients. Regional homogeneity values at the corpus callosum/cingulate gyrus and parietal lobe/middle frontal gyrus were negatively correlated with Hospital Anxiety and Depression scale and disease duration. It was found that the regional homogeneity signal values were significantly lower than in thyroid-associated ophthalmopathy without in dysthyroid optic neuropathy, which may indicate a risk of regional brain dysfunction in dysthyroid optic neuropathy. The results show that regional homogeneity has the potential for early diagnosis and prevent dysthyroid optic neuropathy. In addition, the findings suggest possible mechanisms of dysthyroid optic neuropathy optic nerve injury. They may provide a valuable basis for further research on the pathological mechanisms of dysthyroid optic neuropathy.

Clinical albinism score, presence of nystagmus and optic nerves defects are correlated with visual outcome in patients with oculocutaneous albinism.

Purpose: To correlate clinical features, molecular genetic findings, and visual acuity in a cohort of patients clinically diagnosed with oculocutaneous albinism.Design: Retrospective chart reviewMethods: 58 charts met the inclusion criteria. Clinical examination, ancillary testing, and molecular genetic diagnoses were extracted. A novel clinical albinism score (CAS) was developed.Results: A least one likely pathogenic mutation was found in 44/58 (75.9%) patients. Mutations in the OCA1 gene were the most common (52.3%), followed by OCA2 (34%), OCA4 (2.3%), OA1 (6.8%), and HPS (4.5%). Thirty-four percentage of patients had a complete genotype, 41% had one mutation found and 24% had negative genetic testing. CAS was statistically significantly higher in patients with complete genotype, versus patients with one or no mutations found (p < .01). Better visual acuity was associated with lower CAS and fewer disease-causing mutations (p < .01). Foveal defects and iris transillumination were associated with a higher number of mutations (p < .01). Patients with nystagmus or anomalous optic nerves had worse visual acuity than those who did not (p < .01, p < .05).Conclusions: Patients with a complete genotype were more likely to have higher CAS. Vision loss correlated with complete phenotype and higher CAS, the presence of nystagmus and anomalous optic nerves. Patients with features of albinism in whom an incomplete genotype was found had better vision than those with complete genotype, suggesting a mild occult mutation or modifier variant. Genetic diagnosis is vital for complete diagnosis, counseling, and family planning.

Modeling Retinal Ganglion Cell Dysfunction in Optic Neuropathies.

As in glaucoma and other optic neuropathies cellular dysfunction often precedes cell death, the assessment of retinal ganglion cell (RGC) function represents a key outcome measure for neuroprotective strategies aimed at targeting distressed but still viable cells. RGC dysfunction can be assessed with the pattern electroretinogram (PERG), a sensitive measure of electrical activity of RGCs that is recorded non-invasively in human subjects and mouse models. Here, we offer a conceptual framework based on an intuitive state-transition model used for disease management in patients to identify progressive, potentially reversible stages of RGC dysfunction leading to cell death in mouse models of glaucoma and other optic neuropathies. We provide mathematical equations to describe state-transitions with a set of modifiable parameters that alter the time course and severity of state-transitions, which can be used for hypothesis testing and fitting experimental PERG data. PERG dynamics as a function of physiological stimuli are also used to differentiate phenotypic and altered RGC response dynamics, to assess susceptibility to stressors and to assess reversible dysfunction upon pharmacological treatment.

Do Additional Testing Locations Improve the Detection of Macular Perimetric Defects in Glaucoma?

PURPOSE: To evaluate the ability of additional central testing locations to improve detection of macular visual field (VF) defects in glaucoma. DESIGN: Prospective cross-sectional study. PARTICIPANTS: Four hundred forty healthy people and 499 patients with glaucomatous optic neuropathy (GON) were tested with a fundus tracked perimeter (CMP; CenterVue) using a 24-2 grid with 12 additional macular locations (24-2+). METHODS: Glaucomatous optic neuropathy was identified based on expert evaluation of optic nerve head photographs and OCT scans, independently of the VF. We defined macular defects as locations with measurements outside the 5% and 2% normative limits on total deviation (TD) and pattern deviation (PD) maps within the VF central 10°. Classification was based on the total number of affected macular locations (overall detection) or the largest number of affected macular locations connected in a contiguous cluster (cluster detection). Criteria based on the number of locations and cluster size were used to obtain equivalent specificity between the 24-2 grid and the 24-2+ grids, calculated using false detections in the healthy cohort. Partial areas under the receiver operating characteristic curve (pAUCs) were also compared at specificities of 95% or more. MAIN OUTCOME MEASURES: Matched specificity comparison of the ability to detect glaucomatous macular defects between the 24-2 and 24-2+ grids. RESULTS: At matched specificity, cluster detection identified more macular defects with the 24-2+ grid compared with the 24-2 grid. For example, the mean increase in percentage of detection was 8% (95% confidence interval [CI], 5%-11%) and 10% (95% CI, 7%-13%) for 5% TD and PD maps, respectively, and 5% (95% CI, 2%-7%) and 6% (95% CI, 4%-8%) for the 2% TD and PD maps, respectively. Good agreement was found between the 2 grids. The improvement measured by pAUCs was also significant but generally small. The percentage of eyes with macular defects ranged from about 30% to 50%. Test time for the 24-2+ grid was longer (21% increase) for both cohorts. Between 74% and 98% of defects missed by the 24-2 grid had at least 1 location with sensitivity of < 20 dB. CONCLUSIONS: Visual field examinations with additional macular locations can improve the detection of macular defects in GON modestly without loss of specificity when appropriate criteria are selected.

"Neuroimaging in ethambutol induced optic neuropathy: MRI in time can save the vision".

Ethambutol is an integral part of Antitubercular therapy (ATT) and is often associated with optic neuropathy, However, neuroimaging of ethambutol induced optic neuropathy has been sparsely reported in the literature. We describe the case of a 45-year male patient, diagnosed as Tuberculous spondylodiscitis and was on ATT. Four months after ATT initiation, he presented with visual blurring in both the eyes with bitemporal hemianopia and central scotomas. Visual evoked potential (VEP) revealed prolonged latencies in N75 and P100 waveforms bilaterally. Magnetic Resonance Imaging (MRI) showed optic chiasma and bilateral optic tract hyperintensities on 3D Fluid Attenuated Inversion Recovery (FLAIR) and 3D Double Inversion Recovery (DIR) sequences. Ethambutol was discontinued immediately. On follow-up after 8 weeks, visual acuity reversed back to normal in both eyes.

Relationship between peripheral vasospasm and visual field progression rates in patients with normal-tension glaucoma with low-teen intraocular pressure.

PURPOSE: To investigate the association between peripheral vasospasm and the visual field (VF) progression rate in patients with normal-tension glaucoma (NTG) with low-teen intraocular pressure (IOP). METHODS: The finger temperature of 113 NTG patients was measured before and after exposure to ice water using a Temperature gun (cold pressor test). These patients had confirmed VF progression, despite a low-teen IOP during a follow-up period of >5 years. VF progression rates were calculated as the slope of the visual field index (VFI) and mean deviation (MD) over time. Demographic, systemic, and ocular factors and VF progression rates were compared, based on the cold pressor test results. A regression analysis was used to investigate the factors affecting VF progression rates. RESULTS: Mean age, initial IOP, mean IOP during the follow-up period, and initial VF MD were 57.1 years, 15.8 mmHg, 12.0 mmHg, and -5.2 dB, respectively. When patients were divided into two groups (less vasospasm and more vasospasm) according to changes in temperature after exposure to ice water, the VF progression rate was significantly faster in the group with more vasospasm. In a multiple regression analysis, older age, worse initial VF MD, and greater decrease in finger temperature after ice water exposure were significantly associated with faster VF progression rates. CONCLUSION: An excessive drop in finger temperature after exposure to ice water was significantly associated with faster VF progression in patients with low-teen NTG. This suggests that the blood flow in the optic nerve head may also be disturbed by peripheral vasospasm, accelerating glaucomatous damage regardless of IOP.

Posture-Dependent Collapse of the Optic Nerve Subarachnoid Space: A Combined MRI and Modeling Study.

Purpose: We hypothesize that a collapse of the optic nerve subarachnoid space (ONSAS) in the upright posture may protect the eyes from large translamina cribrosa pressure differences (TLCPD) believed to play a role in various optic nerve diseases (e.g., glaucoma). In this study, we combined magnetic resonance imaging (MRI) and mathematical modeling to investigate this potential ONSAS collapse and its effects on the TLCPD. Methods: First, we performed MRI on six healthy volunteers in 6° head-down tilt (HDT) and 13° head-up tilt (HUT) to assess changes in ONSAS volume (measured from the eye to the optic canal) with changes in posture. The volume change reflects optic nerve sheath (ONS) distensibility. Second, we used the MRI data and mathematical modeling to simulate ONSAS pressure and the potential ONSAS collapse in a 90° upright posture. Results: The MRI showed a 33% decrease in ONSAS volume from the HDT to HUT (P < 0.001). In the upright posture, the simulations predicted an ONSAS collapse 25 mm behind lamina cribrosa, disrupting the pressure communication between the ONSAS and the intracranial subarachnoid space. The collapse reduced the simulated postural increase in TLCPD by roughly 1 mm Hg, although this reduction was highly sensitive to ONS distensibility, varying between 0 and 4.8 mm Hg when varying the distensibility by ±â€…1 SD. Conclusions: The ONSAS volume along the optic nerve is posture dependent. The simulations supported the hypothesized ONSAS collapse in the upright posture and showed that even small changes in ONS stiffness/distensibility may affect the TLCPD.

Association between Topographic Features of the Retinal Nerve Fiber Bundle and Good Visual Acuity in Patients with Glaucoma.

Purpose: Maintaining visual acuity in glaucoma patients is an important part of preventing the deterioration of quality of vision. We identified specific areas of the papillomacular bundle (PMB) that were strongly associated with visual acuity, based on en-face images derived from optical coherence topography (OCT) wide scans.Methods: The study recruited 23 eyes of 21 glaucoma patients (age: 61.3 ± 13.0 years, M: F = 9:12, Humphrey field analyzer-measured mean deviation: -19.9 ± 6.5 dB) with good best-corrected visual acuity (20/20 or more) and a remaining PMB with a maximum width no more than half that of the vertical disc diameter. En-face images were derived from 12 × 9 mm wide-scan images made with DRI-OCT (Triton, Topcon). Averaged en-face images were created by identifying the disc center and fovea line (DFL) and aligning it between images. We then measured the frequency of remaining PMB at 10 µm intervals along a vertical line intersecting the DFL at its midpoint. Finally, we used a logistic analysis in a much larger group of patients to identify cases of glaucoma with low BCVA (<20/20).Results: In the averaged en-face image, the residual PMB area appeared as a high-intensity region above the DFL. Analysis showed that residual PMB was most common in an area 830-870 µm above the DFL. The correlation coefficient of residual PMB in this area to BCVA was -0.57 (p < .01), and among OCT parameters in this residual PMB area, the AUC to identify decreased BCVA was highest for ganglion cell complex thickness (0.85, p < .01), with a cutoff of 87.5 µm.Conclusions: This study identified specific areas of the PMB that were associated with BCVA in wide-scan, en-face OCT images from glaucoma patients. This suggests that it may be possible to identify visual impairment during glaucoma treatment by measuring this area.

Juxtapapillary Deep-Layer Microvasculature Dropout and Retinal Nerve Fiber Layer Thinning in Glaucoma.

PURPOSE: We sought to characterize juxtapapillary (JP) and non-JP microvasculature dropout in patients with primary open-angle glaucoma and to compare their rate of retinal nerve fiber layer (RNFL) thinning. DESIGN: Retrospective cohort study. METHODS: A total of 141 eyes with primary open-angle glaucoma with ≥4 serial optical coherence tomography (OCT) images after initial OCT angiography for ≥2 years were included. Based on OCT angiography imaging, the 3 groups were matched by age and visual field mean deviation: JP group (parapapillary deep-layer microvasculature dropout in contact with the optic disc boundary, n = 47), non-JP group (dropout not reaching the optic disc boundary, n = 47), and no-dropout group (lacking the dropout, n = 47). The RNFL thinning rate was compared among the 3 groups. RESULTS: The rate of RNFL thinning tended to be fastest in the JP group followed by the non-JP group and no-dropout group in all areas except the temporal and nasal sectors. Post hoc analysis revealed that the JP group had significantly faster RNFL thinning than did the no-dropout group in the global area and the inferotemporal and inferonasal sectors (P < .05). When subgroup analysis was performed for subjects in which the main sector of dropout was the inferotemporal sector, the JP group had significantly faster RNFL thinning than the other 2 groups in the corresponding inferotemporal sector (P < .001). CONCLUSION: Eyes with JP microvasculature dropout showed faster RNFL thinning than eyes without dropout. These findings suggest that deep-layer microvasculature dropout, especially in contact with the optic disc boundary, is associated with rapid glaucoma progression.

How Do Patients Feel About Visual Field Testing? Analysis of Subjective Perception of Standard Automated Perimetry.

PURPOSE: A high rate of unreliability is an issue in visual field (VF) testing, especially in elderly patients, and warrants patient education. We assessed whether subjective perception of the visual field test (VFT) is a good predictor of its reliability in different age groups and examined age differences in patients' awareness of VF damage. METHODS: This cross-sectional study investigated 107 VFT results of 54 patients with glaucoma or ocular hypertension. Subjective perceptions were compared to reliability indices for cooperation analysis and to mean deviation results for VF damage analysis, and an age-segregated sub-analysis was performed. RESULTS: Kappa coefficients showed poor agreement between subjective and objective parameters. Nevertheless, there were age differences. Younger patients had a higher positive predictive value and sensitivity in cooperation analysis and a higher negative predictive value in VF damage analysis. CONCLUSIONS: Patients' perception of cooperation in VFT is a poor predictor of its reliability. Although young cooperative patients may be aware of their good cooperation, even the youngest are unaware of their poor performance. This emphasizes the importance of giving proper directions to all patients during VFT to obtain better reliability indices. Younger, healthy patients are more aware of their health status, than those with a damaged VF, regardless of age. Therefore, illness education is crucial in all glaucoma patients.

Development and Implementation of a Handheld Pupillometer for Detection of Optic Neuropathies.

Purpose: Quantitative pupillometry has utility in research settings for measuring optic nerve and autonomic function. We configured a portable device to perform quantitative pupillometry with application to detecting unilateral optic neuropathies in the clinical setting.Materials & methods: Light stimuli were delivered, and pupil diameter responses recorded using customized software implemented on a commercial portable electroretinography device. Increasing pupillary constriction occurred with increasing duration and intensity of full field blue light (470 nm) stimuli in healthy subjects. Flashes of 1 s dim (50 cd/m2) and bright (316 cd/m2) blue light were administered to both eyes of subjects with unilateral optic neuropathies (n = 10) and controls (n = 5). Maximum pupillary constriction (Cmax) for each stimulus was compared between control eyes and optic neuropathy eyes. Cmax for the inter-eye difference curve (Cdiffmax) was compared between control and optic neuropathy subjects.Results: The pupil protocol lasted 15 minutes and was well tolerated by subjects. Cmax for bright and dim stimuli was reduced in eyes with optic neuropathy compared to fellow and control eyes (p < .0005 for all). Inter-eye Cdiffmax was larger in optic neuropathy subjects than control subjects for both dim and bright stimuli (p = .002, <0.0005). There was no overlap between groups for Cmax and Cdiffmax for either stimulus.Conclusions: A portable pupillometer was implemented on a commercial portable electroretinography platform and applied in a pilot manner to subjects with and without unilateral optic neuropathies. Optic neuropathy eyes were distinguished from non-optic neuropathy eyes both within and between subjects.