Myopathy and Ophthalmologic Abnormalities in Association With Multiple Skeletal Muscle Mitochondrial DNA Deletions

BACKGROUND

Establishing a molecular diagnosis of mitochondrial diseases due to pathogenic mitochondrial DNA (mtDNA) variants can be difficult because of varying levels of tissue heteroplasmy, and identifying these variants is important for clinical management. Here, we present clinical and molecular findings in 8 adult patients with classical features of mitochondrial ophthalmologic and/or muscle disease and multiple mtDNA deletions isolated to muscle.

METHODS

The patients were identified via a retrospective review of patients seen in both a tertiary ophthalmology center and a genetics clinic with a clinical diagnosis of chronic progressive external ophthalmoplegia, optic nerve abnormalities, and/or mitochondrial myopathy. Age at onset of symptoms ranged from 18 to 61 years. Ocular manifestations included bilateral optic neuropathy in one patient, bilateral optic disc cupping without optic neuropathy in 2 patients, ptosis in 4 patients, and ocular motility deficits in 2 patients. Five patients had generalized weakness.

RESULTS

Pathogenic variants in mtDNA were not found in the blood or buccal sample from any patient, but 7 of 8 patients had multiple mtDNA deletions identified in muscle tissue. One patient had a single mtDNA deletion identified in the muscle. Heteroplasmy was less than 15% for all of the identified deletions, with the exception of one deletion that had a heteroplasmy of 50%-60%. None of the patients were found to have a nuclear gene variant known to be associated with mitochondrial DNA maintenance.

CONCLUSIONS

mtDNA deletions were identified in adult patients with ophthalmologic and/or musle abnormalities and may underlie their clinical presentations.

The Association Between Craniofacial Fracture Patterns and Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is a rare but potentially devastating complication of craniofacial trauma. Approximately half of patients with TON sustain permanent vision loss. In this study, we sought to identify the most common fracture patterns associated with TON. We performed a retrospective review of craniomaxillofacial CT scans of trauma patients who presented to the R Adams Cowley Shock Trauma Center from 2015 to 2017. Included were adult patients who had orbital fractures with or without other facial fractures. Patients diagnosed with TON by a formal ophthalmologic examination were analyzed. Craniofacial fracture patterns were identified. Bivariate analysis and multivariate logistic regression were performed to identify craniofacial fracture patterns most commonly associated with TON. A total of 574 patients with orbital fractures who met inclusion criteria [15 (2.6%)] were diagnosed with TON. The median [interquartile range (IQR)] age was 44 (28-59) years. Patients with optic canal fractures and sphenoid sinus fractures had greater odds of TON compared with patients who did not have these fracture types [adjusted odds ratio (aOR) 95% confidence interval (CI) 31.8 (2.6->100), 8.1 (2.7-24.4), respectively]. Patients who sustain optic canal and sphenoid sinus fractures in the setting of blunt facial trauma are at increased odds of having a TON. Surgeons and other physicians involved in the care of these patients should be aware of this association.

Ophthalmic and Systemic Factors of Acute Nonarteritic Anterior Ischemic Optic Neuropathy in the Quark207 Treatment Trial

PURPOSE

We describe the baseline ophthalmic and cardiovascular risk factors across countries, race, and sex for the Quark207 treatment trial for acute nonarteritic anterior ischemic optic neuropathy (NAION).

DESIGN

Prospective, randomized controlled clinical trial.

PARTICIPANTS

Adults 50 to 80 years of age with acute NAION recruited from 80 sites across 8 countries.

MAIN OUTCOME MEASURES

Ophthalmic features of NAION and cardiovascular risk factors.

METHODS

We evaluated demographics and clinical and ophthalmologic data, including best-corrected visual acuity (BCVA) and average visual field total deviation (TD), in affected eyes and cup-to-disc ratio in fellow eyes at enrollment. We report the prevalence (mean and standard devition, and median and interquartile range [IQR]) of ophthalmic features and cardiovascular risk factors, stratified by country, race, and sex. We corrected for multiple comparisons using Dunn's test with Bonferroni correction for continuous variables and chi-square testing with Holm-Bonferroni correction for categorical variables.

RESULTS

The study enrolled 500 men and 229 women with a median age of 60 and 61 years (P = 0.027), respectively. Participants were predominantly White (n = 570) and Asian (n = 149). The study eye BCVA was 71 characters (IQR, 53-84 characters; approximately 0.4 logarithm of the minimum angle of resolution), and the TD was -16.5 dB (IQR, -22.2 to -12.6 dB) for stimulus III and -15.7 dB (IQR, -20.8 to -10.9 dB) for stimulus V. The vertical and horizontal cup-to-disc ratio was 0.1 (IQR, 0.1-0.3) for unaffected fellow eyes. The prevalence of cardiovascular risk factors varied among countries. The most notable differences were in the baseline comorbidities and ophthalmologic features, which differed between Asian and White races. Men and women differed with respect to a few clinically meaningful features.

CONCLUSIONS

The cardiovascular risk factors in the NAION cohort varied among the 7 countries, race, and sex, but were not typically more prevalent than in the general population. Ophthalmic features, typical of NAION, generally were consistent across countries, race, and sex, except for worse BCVA and TD in China. Men have a frequency of NAION twice that of women. Having a small cup-to-disc ratio in the fellow eye was the most prevalent risk factor across all demographics. This study suggests that factors, not yet identified, may contribute to the development of NAION.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Bilateral Dilated Superior Ophthalmic Veins in a Patient With an Arteriovenous Dialysis Fistula

A 64-year-old man presented with 4 months of diplopia. He had end-stage renal disease requiring a cephalic transposition brachiocephalic fistula that was no longer in use following successful renal transplantation. On presentation, he had bilateral proptosis, extraocular movement restriction, chemosis, tortuous episcleral vessels, and caruncular injection. Non-contrast CT of the orbits demonstrated dilation of both superior ophthalmic veins, and CT angiography showed asymmetric enlargement of both cavernous sinuses and superior ophthalmic veins. A carotid-cavernous fistula was suspected, but cerebral angiography revealed shunting from the old fistula with intracranial drainage and cerebral venous hypertension. Aberrant retrograde drainage resulted from anatomical compression of the left brachiocephalic vein. The fistula was ligated, and at 1-week follow-up, the patient had marked improvement in extraocular movements and orbital congestion with near complete resolution of diplopia. Postoperative CT angiography obtained 2 months later demonstrated decreased size of both superior ophthalmic veins, consistent with improvement of venous hypertension.

Guidelines of the International Headache Society for Controlled Clinical Trials in Idiopathic Intracranial Hypertension

The quality of clinical trials is essential to advance treatment, inform regulatory decisions and meta-analysis. With the increased incidence of idiopathic intracranial hypertension and the emergence of clinical trials for novel therapies in this condition, the International Headache Society Guidelines for Controlled Clinical Trials in Idiopathic Intracranial Hypertension aims to establish guidelines for designing state-of-the-art controlled clinical trials for idiopathic intracranial hypertension.

Visual Field Pointwise Analysis of the Idiopathic Intracranial Hypertension Weight Trial (IIH:WT)

Purpose

This study was designed to determine if point analysis of the Humphrey visual field (HVF) is an effective outcome measure for people with idiopathic intracranial hypertension (IIH) compared with mean deviation (MD).

Methods

Using the IIH Weight Trial data, we performed a pointwise analysis of the numerical retinal sensitivity. We then defined a medically treated cohort as having MDs between -2 dB and -7 dB and calculated the number of points that would have the ability to change by 7 dB.

Results

The HVF 24-2 mean ± SD MD in the worse eye was -3.5 ± 1.1 dB (range, -2.0 to -6.4 dB). Total deviation demonstrated a preference for the peripheral and blind spot locations to be affected. Points between 0 dB and -10 dB demonstrated negligible ability to improve, compared with those between -10 dB and -25 dB. For the evaluation of the feasibility for a potential medical intervention trial, only 346 points were available for analysis between -10 dB and -25 dB bilaterally, compared with 4123 points in baseline sensitivities of 0 to -10 dB.

Conclusions

Patients with IIH have mildly affected baseline sensitivities in the visual field based on HVF analyzer findings, and the majority of points do not show substantial change over 24 months in the setting of a randomized clinical trial. Most patients with IIH who are eligible for a medical treatment trial generally have the mildest affected baseline sensitivities. In such patients, pointwise analysis offers no advantage over MD in detection of visual field change.

Optic Neuropathies: Current and Future Strategies for Optic Nerve Protection and Repair

Processes that damage the optic nerve, including elevated intraocular pressure, trauma, ischemia, and compression, often cause visual loss for which there is no current treatment [...].

Differentiating Glaucomatous Optic Neuropathy from Non-Glaucomatous Optic Neuropathies Using Deep Learning Algorithms

PURPOSE

A deep learning framework to differentiate glaucomatous optic disc changes (GON) from non-glaucomatous optic neuropathy-related disc changes (NGON).

DESIGN

Cross-sectional study.

METHOD

A deep-learning system was trained, validated, and externally tested to classify optic discs as normal, GON, or NGON using 2,183 digital color fundus photographs. A Single-Center data set of 1,822 images-660 images of NGON, 676 images of GON, and 486 images of normal optic discs-was used for training and validation, whereas 361 photographs from four different data sets were used for external testing. Our algorithm removed the redundant information from the images using an optic disc segmentation (OD-SEG) network, following which we performed transfer learning with various pre-trained networks. Finally, we calculated sensitivity, specificity, F1-score, and precision to show the performance of the discrimination network in the validation and independent external data set.

RESULTS

For classification, the algorithm with the best performance for the Single-Center data set was DenseNet121, with a sensitivity of 95.36%, precision of 95.35%, specificity of 92.19%, and F1 score of 95.40%. For the external validation data, the sensitivity and specificity of our network for differentiating GON from NGON were 85.53% and 89.02%, respectively. The glaucoma specialist who diagnosed those cases in masked fashion, had a sensitivity of 71.05% and a specificity of 82.21%.

CONCLUSIONS

The proposed algorithm for the differentiation of GON from NGON yields results that have a higher sensitivity than those of a glaucoma specialist, and its application for unseen data thus is extremely promising.

Cranial Polyneuropathy Secondary to Remote Iophendylate Myelography

A 68-year-old woman with controlled hypertension, and degenerative joint disease of the spine for which she had undergone several myelograms and three surgeries 30-32 years earlier, presented with a 2 year history of painless, oblique, binocular diplopia. Her prior ophthalmic evaluations were consistent with an isolated left trochlear nerve paresis. She had magnetic resonance imaging (MRI) showing multiple foci of T1-weighted hyperintensities around the midbrain and brainstem thought to represent subarachnoid fat from a ruptured dermoid cyst. An extensive evaluation revealed a left trochlear nerve paresis as well as diminished sensation in the distributions of the first and second divisions of the left trigeminal nerve. Review of her MRI and history of myelograms raised the possibility of focal inflammation from intrathecal iophendylate (Pantopaque®). Repeat MRI was obtained that showed T1-weighted hyperintensities similar to her previous MRI, but in this study, T1-weighted fat suppression imaging also was performed and revealed these foci to be of low signal intensity, consistent with retained iophendylate.

Neuroprotection and Neuroregeneration Strategies Using the rNAION Model: Theory, Histology, Problems, Results and Analytical Approaches

Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common cause of sudden optic nerve (ON)-related vision loss in humans. Study of this disease has been limited by the lack of available tissue and difficulties in evaluating both treatments and the window of effectiveness after symptom onset. The rodent nonarteritic anterior ischemic optic neuropathy model (rNAION) closely resembles clinical NAION in its pathophysiological changes and physiological responses. The rNAION model enables analysis of the specific responses to sudden ischemic axonopathy and effectiveness of potential treatments. However, there are anatomic and genetic differences between human and rodent ON, and the inducing factors for the disease and the model are different. These variables can result in marked differences in lesion development between the two species, as well as in the possible responses to various treatments. These caveats are discussed in the current article, as well as some of the species-associated differences that may be related to ischemic lesion severity and responses.

Post-cataract surgery optic neuropathy: a chronological narrative review of the literature and speculation on pathogenesis

PURPOSE OF REVIEW

To appraise the literature on the incidence of an acute anterior optic neuropathy resembling spontaneous nonarteritic anterior ischemic optic neuropathy (NAION) following uncomplicated cataract surgery and to explore the proposed pathogenesis of both immediate and delayed onset post-cataract surgery optic neuropathy (PCSON).

RECENT FINDINGS

A number of case reports, case series, and retrospective case-controlled, big data, and population-based studies have identified an apparent association between cataract surgery and the occurrence of an acute anterior optic neuropathy that can either be immediate or delayed in onset. However, a recent study found no link between modern day cataract surgery and an increased risk of an acute anterior optic neuropathy.

SUMMARY

Immediate PCSON appears to be related to negative perfusion pressure at the level of the optic disc due to increased intraocular pressure. The pathogenesis of delayed PCSON is unknown but probably multifactorial. Patients who have experienced spontaneous NAION or PCSON in one eye may be at risk of PCSON in the fellow eye.

Elevated perioptic lipocalin-type prostaglandin D synthase concentration in patients with idiopathic intracranial hypertension

The pathophysiology of vision loss and loss of visual field in patients with idiopathic intracranial hypertension with papilloedema is not fully understood. Although elevated CSF pressure induces damage to the optic nerve due to stasis of axoplasmic flow, there is no clear relationship between the severity of papilloedema and CSF pressure. Furthermore, there are cases of purely unilateral papilloedema and cases without papilloedema despite significantly elevated intracranial pressure as well as papilloedema that can persist despite a successfully lowered intracranial pressure. We hypothesize that at least in some of such cases, in addition to purely pressure-induced damage to the optic nerve, the biochemical composition of the CSF in the subarachnoid space surrounding the orbital optic nerve may play a role in the pathogenesis of vision loss. In this retrospective study, we report on lipocalin-type prostaglandin D synthase concentrations in the CSF within the perioptic and lumbar subarachnoid space in 14 patients with idiopathic intracranial hypertension (13 females, mean age 45 ± 13 years) with chronic persistent papilloedema resistant to maximum-tolerated medical therapy and visual impairment. CSF was collected from the subarachnoid space of the optic nerve during optic nerve sheath fenestration and from the lumbar subarachnoid space at the time of lumbar puncture. CSF was analysed for lipocalin-type prostaglandin D synthase and the concentrations compared between the two sites using nephelometry. The mean lipocalin-type prostaglandin D synthase concentration in the perioptic subarachnoid space was significantly higher compared with the concentration in the lumbar subarachnoid space (69 ± 51 mg/l without correction of serum contamination and 89 ± 67 mg/l after correction of serum contamination versus 23 ± 8 mg/l; P < 0.0001, Mann–Whitney U-test). These measurements demonstrate a change and imbalance in the biochemical environment of the optic nerve. Its possible effect is discussed.

Cavernous Malformation of the Optic Nerve and Chiasm: Prompt Suspicion and Surgery Matter

BACKGROUND

Cavernous malformations (CMs) of the optic nerve and chiasm are extremely rare, accounting for less than 1% of all intracranial CMs. Acute, subacute, or progressive visual loss from CM may occur with or without hemorrhage. Prompt surgical excision of the CM offers the best hope to improve or stabilize vision. Given its rarity, optic nerve and chiasm CMs may not be readily suspected. We provide 3 cases of optic nerve and chiasm CM, highlighting key neuroimaging features and the importance of expedited intervention.

METHODS

Case records of the neuro-ophthalmology clinics of the Bascom Palmer Eye Institute and the University of Colorado, and literature review of reported cases of optic CM.

RESULTS

A 49-year-old woman reported acute progressive painless vision loss in the right eye. MRI showed a suprasellar mass with heterogeneity in signal involving the right prechiasmatic optic nerve. Surgical excision of the CM 5 days after onset of visual loss improved vision from 20/300 to 20/30. A 29-year-old woman with acute painless blurred vision in the right eye had anterior chiasmal junctional visual field defects corresponding to a heterogeneously minimally enhancing mass with blood products enlarging the optic chiasm and proximal right optic nerve. Surgical excision of the CM 8 weeks after onset of visual loss improved vision from 20/40 to 20/15 with improved visual fields. A 33-year-old woman with a history of familial multiple CMs, diagnosed at age 18, reported new-onset severe headache followed by blurred vision. MRI showed a hemorrhagic lesion of the optic chiasm and right optic tract. She was 20/20 in each eye with a reported left superior homonymous hemianopia. No intervention was recommended. Vision of the right eye worsened to 20/400 2 months later. The patient was followed over 13 years, and the MRI and visual function remained unchanged. Literature review yielded 87 optic CM cases occurring across gender and nearly all ages with visual loss and headache as the most common presenting symptoms. Optic chiasm is the most common site of involvement (79%). Nearly 95% of reported CM cases were treated with surgery with 81% with improved vision and 1% with worsened vision.

CONCLUSION

MRI features are critical to the diagnosis of optic nerve and chiasm CM and may mimic other lesions. A high index of suspicion by the neuro-ophthalmologist and neuroradiologist leads to early recognition and intervention. Given optic CM displaces and does not infiltrate neural tissue, expedited surgical resection by a neurosurgeon after consideration of other diagnostic possibilities improves visual function in most cases.

Detection of Optic Disc Abnormalities in Color Fundus Photographs Using Deep Learning

BACKGROUND

To date, deep learning-based detection of optic disc abnormalities in color fundus photographs has mostly been limited to the field of glaucoma. However, many life-threatening systemic and neurological conditions can manifest as optic disc abnormalities. In this study, we aimed to extend the application of deep learning (DL) in optic disc analyses to detect a spectrum of nonglaucomatous optic neuropathies.

METHODS

Using transfer learning, we trained a ResNet-152 deep convolutional neural network (DCNN) to distinguish between normal and abnormal optic discs in color fundus photographs (CFPs). Our training data set included 944 deidentified CFPs (abnormal 364; normal 580). Our testing data set included 151 deidentified CFPs (abnormal 71; normal 80). Both the training and testing data sets contained a wide range of optic disc abnormalities, including but not limited to ischemic optic neuropathy, atrophy, compressive optic neuropathy, hereditary optic neuropathy, hypoplasia, papilledema, and toxic optic neuropathy. The standard measures of performance (sensitivity, specificity, and area under the curve of the receiver operating characteristic curve (AUC-ROC)) were used for evaluation.

RESULTS

During the 10-fold cross-validation test, our DCNN for distinguishing between normal and abnormal optic discs achieved the following mean performance: AUC-ROC 0.99 (95 CI: 0.98-0.99), sensitivity 94% (95 CI: 91%-97%), and specificity 96% (95 CI: 93%-99%). When evaluated against the external testing data set, our model achieved the following mean performance: AUC-ROC 0.87, sensitivity 90%, and specificity 69%.

CONCLUSION

In summary, we have developed a deep learning algorithm that is capable of detecting a spectrum of optic disc abnormalities in color fundus photographs, with a focus on neuro-ophthalmological etiologies. As the next step, we plan to validate our algorithm prospectively as a focused screening tool in the emergency department, which if successful could be beneficial because current practice pattern and training predict a shortage of neuro-ophthalmologists and ophthalmologists in general in the near future.

Approaches to Potentiated Neuroprotective Treatment in the Rodent Model of Ischemic Optic Neuropathy

Nonarteritic anterior ischemic optic neuropathy (NAION) commonly causes sudden optic nerve (ON)-related vision loss. The rodent NAION model (rAION) closely resembles NAION in presentation and physiological responses. We identified early rAION-associated optic nerve head (ONH) inflammatory gene expression responses and the anti-inflammatory prostaglandin PGJ₂’s effects on those responses. We hypothesized that blocking pro-inflammatory prostaglandin (PGE₂) production by inhibiting monoacylglycerol lipase or cyclooxygenase activity and co-administering PGJ₂ would potentiate RGC survival following ischemic neuropathy. Deep sequencing was performed on vehicle- and PGJ₂-treated ONHs 3d post-rAION induction. Results were compared against responses from a retinal ischemia model. Animals were treated with PGJ₂ and MAGL inhibitor KML29, or PGJ₂ + COX inhibitor meloxicam. RGC survival was quantified by stereology. Tissue PG levels were quantified by ELISA. Gene expression was confirmed by qPCR. PGJ₂ treatment nonselectively reduced inflammatory gene expression post-rAION. KML29 did not reduce PGE₂ 1d post-induction and KML29 alone increased RGC loss after rAION. Combined treatments did not improve ONH edema and RGC survival better than reported with PGJ₂ alone. KML29′s failure to suppress PGE₂ ocular synthesis, despite its purported effects in other CNS tissues may result from alternative PG synthesis pathways. Neither KML29 nor meloxicam treatment significantly improved RGC survival compared with vehicle. While exogenous PGJ₂ has been shown to be neuroprotective, treatments combining PGJ₂ with these PG synthesis inhibitors do not enhance PGJ₂’s neuroprotection.

Traumatic Optic Neuropathy

A host of different types of direct and indirect, primary and secondary injuries can affect different portions of the optic nerve(s). Thus, in the setting of penetrating as well as nonpenetrating head or facial trauma, a high index of suspicion should be maintained for the possibility of the presence of traumatic optic neuropathy (TON). TON is a clinical diagnosis, with imaging frequently adding clarification to the full nature/extent of the lesion(s) in question. Each pattern of injury carries its own unique prognosis and theoretical best treatment; however, the optimum management of patients with TON remains unclear. Indeed, further research is desperately needed to better understand TON. Observation, steroids, surgical measures, or a combination of these are current cornerstones of management, but statistically significant evidence supporting any particular approach for TON is absent in the literature. Nevertheless, it is likely that novel management strategies will emerge as more is understood about the converging pathways of various secondary and tertiary mechanisms of cell injury and death at play in TON. In the meantime, given our current deficiencies in knowledge regarding how to best manage TON, "primum non nocere" (first do no harm) is of utmost importance.

Persistent Globe Flattening in Astronauts following Long-Duration Spaceflight

Posterior globe flattening has been well-documented in astronauts both during and after long-duration space flight (LDSF) and has been observed as early as 10 days into a mission on the International Space Station. Globe flattening (GF) is thought to be caused by the disc centred anterior forces created by elevated volume and/or pressure within the optic nerve sheath (ONS). This might be the result of increased intracranial pressure, increased intraorbital ONS pressure from compartmentalisation or a combination of these mechanisms. We report posterior GF in three astronauts that has persisted for 7 years or more following their return from LDSFs suggesting that permanent scleral remodelling may have occurred.

Artificial Intelligence to Detect Papilledema from Ocular Fundus Photographs

BACKGROUND

Nonophthalmologist physicians do not confidently perform direct ophthalmoscopy. The use of artificial intelligence to detect papilledema and other optic-disk abnormalities from fundus photographs has not been well studied.

METHODS

We trained, validated, and externally tested a deep-learning system to classify optic disks as being normal or having papilledema or other abnormalities from 15,846 retrospectively collected ocular fundus photographs that had been obtained with pharmacologic pupillary dilation and various digital cameras in persons from multiple ethnic populations. Of these photographs, 14,341 from 19 sites in 11 countries were used for training and validation, and 1505 photographs from 5 other sites were used for external testing. Performance at classifying the optic-disk appearance was evaluated by calculating the area under the receiver-operating-characteristic curve (AUC), sensitivity, and specificity, as compared with a reference standard of clinical diagnoses by neuro-ophthalmologists.

RESULTS

The training and validation data sets from 6779 patients included 14,341 photographs: 9156 of normal disks, 2148 of disks with papilledema, and 3037 of disks with other abnormalities. The percentage classified as being normal ranged across sites from 9.8 to 100%; the percentage classified as having papilledema ranged across sites from zero to 59.5%. In the validation set, the system discriminated disks with papilledema from normal disks and disks with nonpapilledema abnormalities with an AUC of 0.99 (95% confidence interval [CI], 0.98 to 0.99) and normal from abnormal disks with an AUC of 0.99 (95% CI, 0.99 to 0.99). In the external-testing data set of 1505 photographs, the system had an AUC for the detection of papilledema of 0.96 (95% CI, 0.95 to 0.97), a sensitivity of 96.4% (95% CI, 93.9 to 98.3), and a specificity of 84.7% (95% CI, 82.3 to 87.1).

CONCLUSIONS

A deep-learning system using fundus photographs with pharmacologically dilated pupils differentiated among optic disks with papilledema, normal disks, and disks with nonpapilledema abnormalities. (Funded by the Singapore National Medical Research Council and the SingHealth Duke-NUS Ophthalmology and Visual Sciences Academic Clinical Program.).

Investigating the diverse potential of a multi-purpose legume, Lablab purpureus (L.) Sweet, for smallholder production in East Africa

Climate change is posing severe challenges in Africa, where resilient crops are urgently needed to withstand drought periods and unreliable rainfall. Multi-purpose legume species, such as lablab (Lablab purpureus (L.) Sweet), have been under-utilized yet have the potential to overcome climate challenges. While lablab is native to Africa, there are few characterized varieties and it is under-utilized by smallholder farmers due to a lack of information and access to varieties. Knowledge is especially lacking on the performance of this crop by genotype, management, and environment. We conducted a two-year field study at two sites to evaluate 29 lablab cultivars under sole and maize intercrop management, with 14 cultivars selected for in-depth study. Cultivars were evaluated on vegetative biomass and grain yield production, with N fixation assessed for one site year. Biomass and grain production differed across environments and cultivars, with only biomass affected by intercropping. Average grain yield was substantially reduced to only 37 kg ha-1 in environments with maximum temperatures greater than 33°C, but biomass production yielded comparable amounts across high temperatures and in dry (<500 mm rainfall) environments. Tradeoffs were found between biomass and grain yield across high yielding cultivars, with the top three grain accessions averaging 612 kg ha-1 of grain and 1.97 Mg ha-1 biomass whereas the top three biomass accessions produced 327 kg ha-1 grain and 2.52 Mg ha-1 biomass across all environments. In a comparison of production and N fixation measurements, cultivars were identified which may have high performance in both. Suitability of lablab for grain and biomass production were visualized across Tanzania in a map comparing max temperature thresholds for grain and biomass against average regional livestock populations. This provides a way forward for identifying potential areas for lablab cultivation as a novel means to enhance fodder and pulse production with smallholder farmers.

Implications of monocular vision for racing drivers

We performed two experiments to investigate how monocular vision and a monocular generalized reduction in vision (MRV) impact driving performance during racing. A total of 75 visually normal students or professional racing drivers, were recruited for the two experiments. Driving performance was evaluated under three visual conditions: normal vision, simulated monocularity and simulated monocular reduction in vision. During the driving scenario, the drivers had to detect and react to the sudden intrusion of an opponent's racing car into their trajectory when entering a turn. Generalized Linear Mixed Models (GLMMs) and ANOVA were then used to explore how monocular vision and monocular reduction in vision affect drivers' performance (crash and reaction time) while confronting them with critical situations. The results show that drivers under monocular condition are from 2.1 (95% CI 1.11-4.11, p = .024) to 6.5 (95% CI 3.91-11.13; p = .0001) times more likely to collide with target vehicles compared with their baseline (binocular) condition, depending on the driving situation. Furthermore, there was an average increase in reaction time from 64 ms (p = .029) to 126 ms (p = .015) under monocular condition, depending on the critical driving situation configuration. This study objectively demonstrates that monocularity has a significant impact on driving performance and safety during car racing, whereas performance under monocular reduction in vision conditions is less affected.

An overview of spaceflight-associated neuro-ocular syndrome (SANS)

Over the last decade, the National Aeronautics and Space Administration's (NASA) Space Medicine Division has documented a variety of unusual physiological and pathological neuro-ophthalmic findings in astronauts during and following long duration space flight. These ndings include optic disc swelling, globe flattening, choroidal folds, and hyperopic shifts in refraction. Cephalad fluid shift has been proposed as a possible unifying etiology, but the specific mechanism responsible for these changes remains obscure. This manuscript reviews the history, clinical findings, and potential neurophysiological etiologies for spaceflight-associated neuro-ocular syndrome.

Magnetic resonance imaging findings in Parinaud's syndrome: comparing pineal mass findings to other etiologies

PURPOSE

In a recent study, it was found that, although intrinsic midbrain signal abnormality (IMSA) on MRI is associated with Parinaud's syndrome (PS) in patients with pineal gland masses (PM), it had no predictive value with respect to resolution of PS. We sought to compare the PM and non-pineal etiologies (NPE) of PS by reviewing imaging features of PS and whether or not they are predictive of resolution of symptoms.

METHODS

We reviewed electronic medical records from 1980 to 2017 and identified 71 patients with PS from any etiology who had MR imaging: 26 with PM and 45 with NPE. We subdivided the 45 NPE patients into those with intrinsic midbrain lesions (IMBL) (n = 23) and those with extrinsic midbrain lesions (EMBL) (n = 22). PS resolution and hydrocephalus data were collected. Imaging studies were reviewed for the presence of IMSA and hydrocephalus.

RESULTS

PS patients with EMBL were less likely to have IMSA than those with PM or IMBL (p ≤0.001). PS resolution occurred more commonly with PM than IMBL and NPE (p = 0.03, p = 0.01). For all NPE patients, resolution of PS occurred with equal frequency in patients with and without IMSA (p = 1.00). Hydrocephalus occurred more frequently in patients with PM and EMBL than IMBL (p = 0.01, p = 0.03).

CONCLUSIONS

IMSA is present more often in patients with PS from PM or IMBL than in patients with EMBL. EMBL, including PM, have an increased likelihood for PS resolution. There is no predictive value of IMSA with respect to resolution of PS in NPE as well as PM.

Neural network and logistic regression diagnostic prediction models for giant cell arteritis: development and validation

PURPOSE

To develop and validate neural network (NN) vs logistic regression (LR) diagnostic prediction models in patients with suspected giant cell arteritis (GCA). Design: Multicenter retrospective chart review.

METHODS

An audit of consecutive patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at 14 international medical centers. The outcome variable was biopsy-proven GCA. The predictor variables were age, gender, headache, clinical temporal artery abnormality, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level. The data were divided into three groups to train, validate, and test the models. The NN model with the lowest false-negative rate was chosen. Internal and external validations were performed.

RESULTS

Of 1,833 patients who underwent TABx, there was complete information on 1,201 patients, 300 (25%) of whom had a positive TABx. On multivariable LR age, platelets, jaw claudication, vision loss, log C-reactive protein, log erythrocyte sedimentation rate, headache, and clinical temporal artery abnormality were statistically significant predictors of a positive TABx (P≤0.05). The area under the receiver operating characteristic curve/Hosmer-Lemeshow P for LR was 0.867 (95% CI, 0.794, 0.917)/0.119 vs NN 0.860 (95% CI, 0.786, 0.911)/0.805, with no statistically significant difference of the area under the curves (P=0.316). The misclassification rate/false-negative rate of LR was 20.6%/47.5% vs 18.1%/30.5% for NN. Missing data analysis did not change the results.

CONCLUSION

Statistical models can aid in the triage of patients with suspected GCA. Misclassification remains a concern, but cutoff values for 95% and 99% sensitivities are provided (https://goo.gl/THCnuU).

Long-term efficacy of fractionated conformal radiotherapy for the management of primary optic nerve sheath meningioma

BACKGROUND/AIM

Fractionated conformal radiotherapy (FCRT) is now used to treat vision-threatening optic nerve sheath meningioma (ONSM), but long-term efficacy and safety data are lacking; the purpose of this study was to assess these key data.

METHODS

This is a retrospective chart review with prospective follow-up of adult patients treated with FCRT for primary ONSM at four academic medical centres between 1995 and 2007 with ≥10 years of follow-up after treatment.

RESULTS

16 patients were identified with a mean post-treatment follow-up of 14.6 years (range: 10.5-20.7 years). The mean age at symptom onset was 47.6 years (range: 36-60 years). FCRT was performed at a mean of 2.3 years after symptom onset (range: 0.2-14.0 years). At last follow-up, visual acuity had improved or stabilised in 14 of the 16 (88%) patients, and 11 (69%) had retained or achieved ≥20/40. The mean deviation on automated perimetry remained stable (-14.5 dB pretreatment vs -12.2 dB at last follow-up; p=0.68, n=10). Two (11%) patients had persistent pain, proptosis or diplopia, compared with six (38%) pretreatment (p=0.11). Two (13%) patients developed radiation retinopathy more than 6 months after completion of therapy, one (50%) of whom had worse visual acuity compared with pretreatment. No patient developed tumour involvement or radiation damage in the fellow eye.

CONCLUSION

FCRT stabilises or improves visual function in patients with primary ONSM and is associated with a low risk of significant ocular sequelae. This treatment should be considered instead of surgery in patients with primary ONSM who require intervention due to loss of visual sensory and/or ocular motor function.

Acute Transient Oculomotor Nerve Palsy from Presumed Cavernous Angioma in an Infant

Cavernous angiomas of the cranial nerves are extremely rare, and those of the oculomotor (third) cranial nerve are rarer still, with no previous cases having been reported in the literature. We report herein the first case of a presumed cavernous angioma involving the subarachnoid portion of the left third nerve presenting as an acute left third nerve palsy in an infant. The child was followed without intervention and the palsy completely resolved. Given the poor functional results with attempted surgical excision and the potential for spontaneous improvement in oculomotor nerve function, it is reasonable to follow patients with these lesions without intervention.

Carotid-cavernous fistula: current concepts in aetiology, investigation, and management

A carotid-cavernous fistula (CCF) is an abnormal communication between arteries and veins within the cavernous sinus and may be classified as either direct or dural. Direct CCFs are characterized by a direct connection between the internal carotid artery (ICA) and the cavernous sinus, whereas dural CCFs result from an indirect connection involving cavernous arterial branches and the cavernous sinus. Direct CCFs frequently are traumatic in origin and also may be caused by rupture of an ICA aneurysm within the cavernous sinus, Ehlers-Danlos syndrome type IV, or iatrogenic intervention. Causes of dural CCFs include hypertension, fibromuscular dysplasia, Ehlers-Danlos type IV, and dissection of the ICA. Evaluation of a suspected CCF often involves non-invasive imaging techniques, including standard tonometry, pneumotonometry, ultrasound, computed tomographic scanning and angiography, and/or magnetic resonance imaging and angiography, but the gold standard for classification and diagnosis remains digital subtraction angiography. When a direct CCF is confirmed, first-line treatment is endovascular intervention, which may be accomplished using detachable balloons, coils, liquid embolic agents, or a combination of these tools. As dural CCFs often resolve spontaneously, low-risk cases may be managed conservatively. When invasive treatment is warranted, endovascular intervention or stereotactic radiosurgery may be performed. Modern endovascular techniques offer the ability to successfully treat CCFs with a low morbidity and virtually no mortality.

Quantitative Analysis of the Displacement of the Anterior Visual Pathway by Pituitary Lesions and the Associated Visual Field Loss

Purpose

To evaluate quantitatively the relationship between the displacement of anterior visual pathway structures by pituitary tumors and visual field damage with the goal of improving diagnosis and management.

Methods

Subjects had pituitary macroadenomas and both magnetic resonance imaging (MRI) and static perimetry. Neuroradiologists measured the displacement of anterior visual pathway structures and right–left tumor asymmetry. To quantify the degree and laterality of visual field loss, we used algorithms from the neurologic hemifield test to analyze each right–left pair of visual fields with respect to temporal asymmetry, the proportion of loss that was temporal, total asymmetry, and total damage. We compared these metrics with the displacement of anterior visual pathway structures and tumor asymmetry.

Results

Of 114 subjects, 64 (56%) were male and the median age was 57 years (range, 14–88). The summation of vision loss in both eyes and the proportion of temporal loss were statistically significantly related to the maximum displacement of the anterior visual pathway (both P < 0.001 for fit of linear regression). The relationship between the asymmetry of visual field loss in the two eyes and the subjective assignment of tumor asymmetry on MRI did not achieve statistical significance (P = 0.06 by analysis of variance).

Conclusions

Displacement of the anterior visual pathway by pituitary tumors is associated with both the total amount of visual field loss and the proportion of temporal visual field loss. Although there was right–left asymmetry of vision loss in some subjects, it was not related to the subjective assessment of tumor asymmetry.

Post-Cataract Surgery Optic Neuropathy: Prevalence, Incidence, Temporal Relationship, and Fellow Eye Involvement

PURPOSE

To reassess the prevalence and incidence of post-cataract surgery optic neuropathy (PCSON) in the modern era.

DESIGN

Retrospective cohort study.

METHODS

Setting: Single-center tertiary care practice.

STUDY POPULATION

All patients with a diagnosis of nonarteritic anterior ischemic optic neuropathy (NAION) seen in the Wilmer Eye Network system between January 1, 2010 and December 31, 2014 were included. Inclusion was based on the following: (1) a history of an acute unilateral decrease in vision, (2) a visual field defect consistent with NAION, (3) a relative afferent pupillary defect, (4) observed optic disc swelling, and (5) no other etiology being found.

MAIN OUTCOME MEASURES

The prevalence and incidence of PCSON and the temporal association between surgery and onset of PCSON. The secondary outcome was the risk of PCSON in the fellow eye of patients with prior unilateral spontaneous NAION.

RESULTS

One hundred eighty-eight patients had developed NAION during the study period. Of these, 18 (9.6%) had undergone cataract surgery (CS) during the year prior to developing NAION. There was no significant temporal pattern associated with the distribution of NAION cases (P = .28). The incidence of PCSON in patients who had noncomplex CS was 10.9 cases per 100 000 (95% CI, 1.3, 39.4).

CONCLUSIONS

Our data indicate that both the prevalence and incidence of NAION after modern CS are comparable to those of the general population and that there is no significant temporal relationship between modern CS and the subsequent development of NAION in the operated eye. Thus, although this study has inherent biases owing to its retrospective nature, concern regarding an increased risk of PCSON in the fellow eye in patients who have experienced it or spontaneous NAION in 1 eye may be unwarranted.

Comparison of Visual Outcomes of Nonarteritic Anterior Ischemic Optic Neuropathy in Patients with and without Diabetes Mellitus

PURPOSE

Diabetic patients have a greater risk of nonarteritic anterior ischemic optic neuropathy (NAION) than nondiabetic patients. We compare visual outcomes, prevalence of bilateral/sequential ION, and predictors of visual outcomes in NAION between diabetic and nondiabetic patients.

DESIGN

Case-control study.

PARTICIPANTS

All 231 patients with NAION seen by the Neuro-Ophthalmology Service, Wilmer Eye Institute, between 2002 and 2011 were screened for study inclusion.

METHODS

Patients presenting within 4 weeks of symptom onset (30 with diabetes mellitus, 62 control patients) were included in baseline demographic assessments of vascular risk factors. Interval and final visual outcomes (logarithm of the minimum angle of resolution [logMAR] visual acuity [VA]) were evaluated in the 81 patients in this group with clinical follow-up for ≥3 months, and population average logistic regression models were used to determine risk factors for worse visual outcomes.

MAIN OUTCOME MEASURES

Visual acuity at last follow-up.

RESULTS

The median follow-up duration was 38.7 weeks in diabetic patients and 52.9 weeks in nondiabetic patients. The majority (92.5%) of patients presented within 2 weeks of symptom onset. In nondiabetic patients, the most prevalent risk factor for NAION was hyperlipidemia (62.9%); for diabetic patients, NAION risk factors included hypertension (83.3%), hyperlipidemia (83.3%), and small cup-to-disc ratio (63.3%). Sequential NAION occurred in 36.8% of diabetic patients and 20.9% of nondiabetic patients. At last follow-up, 48% of diabetic and 62% of nondiabetic patients had VA better than 20/40. Similar proportions of diabetic and nondiabetic patients (8 [27%] diabetic and 14 [22.5%] nondiabetic patients) recorded a final follow-up vision of 1.0 logMAR or worse at a minimum of 3 months. Ischemic heart disease (odds ratio [OR], 7.21; P < 0.001) and greater age (OR, 1.05; P = 0.045) were associated with increased risk for final VA <20/200 in the multiple regression model (OR, 4.35; P = 0.011).

CONCLUSIONS

The VA at presentation and at final follow-up in diabetic patients with NAION were not significantly different from nondiabetic controls, although diabetic patients had a higher prevalence of cardiovascular risk factors. Ischemic heart disease and greater age, but not diabetes, independently correlated with worse VA outcome.

A Single Intravitreal Injection of Ranibizumab Provides No Neuroprotection in a Nonhuman Primate Model of Moderate-to-Severe Nonarteritic Anterior Ischemic Optic Neuropathy

PURPOSE

Ranibizumab, a vascular endothelial growth factor-antagonist, is said to be neuroprotective when injected intravitreally in patients with nonarteritic anterior ischemic optic neuropathy (NAION). We evaluated the efficacy of a single intravitreal (IVT) injection of ranibizumab in a nonhuman primate model of NAION (pNAION).

METHODS

We induced pNAION in one eye of four adult male rhesus monkeys using a laser-activated rose Bengal induction method. We then immediately injected the eye with either ranibizumab or normal saline (NS) intravitreally. We performed a clinical assessment, optical coherence tomography, electrophysiological testing, fundus photography, and fluorescein angiography in three of the animals (one animal developed significant retinal hemorrhages and, therefore, could not be analyzed completely) prior to induction, 1 day and 1, 2, and 4 weeks thereafter. Following the 4-week analysis of the first eye, we induced pNAION in the contralateral eye and then injected either ranibizumab or NS, whichever substance had not been injected in the first eye. We euthanized all animals 5 to 12 weeks after the final assessment of the second eye and performed both immunohistochemical and light and electron microscopic analyses of the retina and optic nerves of both eyes.

RESULTS

A single IVT dose of ranibizumab administered immediately after induction of pNAION resulted in no significant reduction of clinical, electrophysiological, or histologic damage compared with vehicle-injected eyes.

CONCLUSIONS

A single IVT dose of ranibizumab is not neuroprotective when administered immediately after induction of pNAION.

Dendrimers Target the Ischemic Lesion in Rodent and Primate Models of Nonarteritic Anterior Ischemic Optic Neuropathy

Introduction

Polyamidoamine dendrimer nanoparticles (~ 4 nanometers) are inert polymers that can be linked to biologically active compounds. These dendrimers selectively target and accumulate in inflammatory cells upon systemic administration. Dendrimer-linked compounds enable sustained release of therapeutic compounds directly at the site of damage. The purpose of this study was to determine if dendrimers can be used to target the optic nerve (ON) ischemic lesion in our rodent and nonhuman primate models of nonarteritic anterior ischemic optic neuropathy (NAION), a disease affecting >10,000 individuals in the US annually, and for which there currently is no effective treatment.

Methods

NAION was induced in male Long-Evans rats (rNAION) and in one adult male rhesus monkey (pNAION) using previously described procedures. Dendrimers were covalently linked to near-infrared cyanine-5 fluorescent dye (D-Cy5) and injected both intravitreally and systemically (in the rats) or just systemically (in the monkey) to evaluate D-Cy5 tissue accumulation in the eye and optic nerve following induction of NAION.

Results

Following NAION induction, Cy-5 dendrimers selectively accumulated in astrocytes and circulating macrophages. Systemic dendrimer administration provided the best penetration of the ON lesion site when injected shortly after induction. Systemic administration 1 day post-induction in the pNAION model gave localization similar to that seen in the rats.

Conclusions

Dendrimers selectively target the ischemic ON lesion after induction of both rNAION and pNAION. Systemic nanoparticle-linked therapeutics thus may provide a powerful, targeted and safe approach to NAION treatment by providing sustained and focused treatment of the cells directly affected by ischemia.

Visual loss after corrective surgery for pediatric scoliosis: incidence and risk factors from a nationwide database

BACKGROUND CONTEXT

Perioperative visual loss (POVL) after spinal deformity surgery is an uncommon but severe complication. Data on the incidence and risk factors of this complication after corrective surgery in the pediatric population are limited.

PURPOSE

The present study aimed to investigate nationwide estimates of POVL after corrective surgery for pediatric scoliosis.

STUDY DESIGN

This is a retrospective study that uses a nationwide database.

PATIENT SAMPLE

The sample includes 42,339 patients under the age of 18 who underwent surgery for idiopathic scoliosis.

OUTCOME MEASURES

The outcome measures were incidence of POVL and risk factors.

METHODS

Patients under the age of 18 who underwent elective surgery for idiopathic scoliosis between 2002 and 2011 were identified using the Nationwide Inpatient Sample database. The incidence of POVL (ischemic optic neuropathy, central retinal artery occlusion, or cortical blindness) was estimated after application of discharge weights. Demographics, comorbidities, and operative parameters were compared between patients with and without visual loss. A multivariate logistic regression was performed to identify significant risk factors for POVL development. No funds were received in support of this work.

RESULTS

The incidence of POVL was 1.6 per 1,000 procedures (0.16%). Patients with visual loss were significantly more likely to be younger and male, have Medicaid as insurance, and undergo fusion of eight or more spinal levels compared with patients without visual loss. Following multivariate analysis, older patients (odds ratio [OR]: 0.84; 95% confidence interval [CI]: 0.77-0.91) and female patients (OR: 0.08; 95% CI: 0.04-0.14) were significantly less likely to develop POVL compared with younger and male patients. On the other hand, having Medicaid as insurance (OR: 2.13;95% CI: 1.32-3.45), history of deficiency anemia (OR: 8.64; 95% CI: 5.46-14.31), and fusion of eight or more spinal levels (OR: 2.40; 95% CI: 1.34-4.30) were all independently associated with POVL.

CONCLUSIONS

In this nationwide study, the incidence of POVL after scoliosis surgery in patients under the age of 18 was estimated at 0.16%, similar to the rate reported in adult patients. Cortical blindness accounted for all cases of POVL in the present study. Younger patients, patients with history of deficiency anemia, and patients undergoing long-segment fusions may be at increased risk of POVL after corrective surgery for pediatric scoliosis.

Peripapillary Retinal Nerve Fiber Layer Swelling Predicts Peripapillary Atrophy in a Primate Model of Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose

To determine the relationship between peripapillary retinal nerve fiber layer (PRNFL) swelling and eventual PRNFL atrophy, and between PRNFL swelling/atrophy and neural function, in a nonhuman primate model of nonarteritic anterior ischemic optic neuropathy (pNAION).

Methods

pNAION was induced in five normal, adult male rhesus monkeys by laser activation of intravenously injected rose bengal at the optic nerve head. Spectral-domain optical coherence tomography measurements of the PRNFL were performed at baseline; 1 day; 1, 2, and 4 weeks; and several later times over a period of an additional 2 to 3 months. Simultaneous pattern-reversal electroretinograms (PERGs) and visual evoked potentials (VEPs) were recorded and color fundus photographs taken at the same time points.

Results

In all cases, initial PRNFL swelling was associated with atrophy, and the greater the initial swelling, the greater the degree of eventual atrophy (r = 0.65, P = 0.0002). The change in PRNFL thickness closely correlated with VEP amplitude loss (r = 0.90), although this relationship was only a strong trend (P = 0.083). Furthermore, VEP amplitude loss closely correlated with PERG N95 amplitude loss (r = 0.80, P = 0.00002)

Conclusions

In our model of human NAION, the degree of initial PRNFL swelling correlated with the severity of atrophy. Areas that did not swell developed little to no atrophy. The amount of PRNFL loss was reflected in VEP and PERG N95 amplitude reductions.