Traumatic rupture of the inferior rectus muscle: case report and review of the literature

Traumatic inferior rectus muscle rupture secondary to blunt injury in the absence of associated orbital or ocular fractures or injury is rarely encountered, and there are limited published reports on subsequent surgical repair. We present the case of a 74-year-old man with complete inferior rectus transection following a fall with facial strike. A computed tomography scan of the face was unremarkable. Surgical exploration and repair of the muscle was performed by hooking the inferior oblique muscle to identify the inferior rectus muscle. Subsequent strabismus surgery was performed for residual binocular diplopia, resulting in excellent anatomic and visual outcomes and postoperative ocular alignment.

Epigenetic Regulation of Optic Nerve Development, Protection, and Repair

Epigenetic factors are known to influence tissue development, functionality, and their response to pathophysiology. This review will focus on different types of epigenetic regulators and their associated molecular apparatus that affect the optic nerve. A comprehensive understanding of epigenetic regulation in optic nerve development and homeostasis will help us unravel novel molecular pathways and pave the way to design blueprints for effective therapeutics to address optic nerve protection, repair, and regeneration.

Ophthalmic manifestations of dementing disorders

PURPOSE OF REVIEW

Dementia is a term for loss of memory, language, problem-solving, and other thinking abilities, which significantly interferes with daily life. Certain dementing conditions may also affect visual function. The eye is an accessible window to the brain that can provide valuable information for the early diagnosis of people who suffer from Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies as well as from more rare causes of dementias, such as Creutzfeldt-Jacob and Huntington's diseases. Herein, we present the ocular manifestations of neurocognitive disorders focusing on the neuro-ophthalmic ones and further discuss potential ocular biomarkers that could help in early detection of these disorders.

RECENT FINDINGS

Ophthalmic examination along with the recent developments in in-vivo testing have provided a strong foundation of useful knowledge about brain disorder in neurodegenerative diseases without the need for invasive studies. Currently, a number of visual measures, such as visual acuity, contrast sensitivity, pupil response, and saccades in addition to various ophthalmic tests, such as electroretinogram, visual evoked potential, optical coherence tomography (OCT), and OCT-angiography have been widely used and evaluated as potential biomarkers for different stages of dementia.

SUMMARY

Ophthalmologic and neuro-ophthalmic evaluation is evolving as an important part of the early diagnosis and management of people with dementia. A particular focus on ocular biomarkers in dementing illnesses has arisen over the past few years and there are several promising measures and imaging tools that have been proposed as potential biomarkers for these diseases.

Optic nerve sheath meningioma

PURPOSE OF REVIEW

Optic nerve sheath meningiomas (ONSMs) are rare benign tumors of the anterior visual pathway which present with slowly progressive and painless vision loss and account for approximately 2% of all orbital tumors. This article provides an overview as well as an update on the ONSMs with regards to cause, epidemiology, clinical presentation, diagnosis, and management in adults and pediatric population.

RECENT FINDINGS

The clinical presentation and prognosis of ONSMs can vary and largely depend on the location of tumor as well as the histologic type. Overall, the diagnosis is based on clinical presentation, examination, and neuroimaging findings. Nevertheless, delays in diagnosis or misdiagnosis are not uncommon and can result in higher morbidity rates. Recent advances in diagnostic as well as more effective and less-invasive treatment options are discussed in this review.

SUMMARY

ONSMs are a rare cause of slowly progressive and inexorable visual loss. Although ONSM diagnosis depends on the characteristic clinical and radiologic findings, prompt diagnosis, and appropriate management is critical for favorable visual outcomes. Thus, current focus is optimizing diagnostic as well-treatment methods for patients with ONSMs.

Orbital disease in neuro-ophthalmology

PURPOSE OF REVIEW

Orbital disease represents a diverse spectrum of pathology and can result in a variety of neuro-ophthalmic manifestations. The aim of this review is to provide updates on recent advances in our understanding of orbital disease secondary to thyroid eye disease, myositis, IgG4-related disease, sarcoidosis, granulomatosis with polyangiitis and various tumours.

RECENT FINDINGS

With regards to thyroid eye disease, there have been recent advances in the development of steroid-sparing therapies, new modalities for objectively monitoring disease activity and increased understanding of the role of environmental risk factors. There has been interest in characterizing the clinical course and underlying mechanism of optic nerve disease secondary to orbital disorders, which has led to advances in how we monitor for and prevent permanent vision loss. Increased knowledge of orbital tumour subtype histopathology and the development of novel classification systems has had prognostic value and aided medical decision-making.

SUMMARY

Orbital disease occurs secondary to a wide variety of diseases and can lead to neuro-ophthalmic manifestations with significant morbidity. Advances in our understanding of different subtypes of orbital disease have improved our ability to treat these potentially debilitating conditions.

Steroid-sparing maintenance immunotherapy for MOG-IgG associated disorder

OBJECTIVE

Myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG) associated disorder (MOGAD) often manifests with recurrent CNS demyelinating attacks. The optimal treatment for reducing relapses is unknown. To help determine the efficacy of long-term immunotherapy in preventing relapse in patients with MOGAD, we conducted a multicenter retrospective study to determine the rate of relapses on various treatments.

METHODS

We determined the frequency of relapses in patients receiving various forms of long-term immunotherapy for MOGAD. Inclusion criteria were history of ≥1 CNS demyelinating attacks, MOG-IgG seropositivity, and immunotherapy for ≥6 months. Patients were reviewed for CNS demyelinating attacks before and during long-term immunotherapy.

RESULTS

Seventy patients were included. The median age at initial CNS demyelinating attack was 29 years (range 3-61 years; 33% <18 years), and 59% were female. The median annualized relapse rate (ARR) before treatment was 1.6. On maintenance immunotherapy, the proportion of patients with relapse was as follows: mycophenolate mofetil 74% (14 of 19; ARR 0.67), rituximab 61% (22 of 36; ARR 0.59), azathioprine 59% (13 of 22; ARR 0.2), and IV immunoglobulin (IVIG) 20% (2 of 10; ARR 0). The overall median ARR on these 4 treatments was 0.3. All 9 patients treated with multiple sclerosis (MS) disease-modifying agents had a breakthrough relapse on treatment (ARR 1.5).

CONCLUSION

This large retrospective multicenter study of patients with MOGAD suggests that maintenance immunotherapy reduces recurrent CNS demyelinating attacks, with the lowest ARR being associated with maintenance IVIG therapy. Traditional MS disease-modifying agents appear to be ineffective. Prospective randomized controlled studies are required to validate these conclusions.

Surgical Responses and Outcomes of Bilateral Medial Rectus Recession in Esotropia With Spinocerebellar Ataxia

PURPOSE

To evaluate the surgical responses and outcomes of bilateral medial rectus (BMR) recession in esotropic patients with spinocerebellar ataxia (SCA) and to compare the results with normal controls.

METHODS

The medical records of patients with SCA who underwent strabismus surgery for esotropia between 2006 and 2015 were reviewed retrospectively. Five esotropic patients with SCA (SCA group) and 10 esotropic patients without neurologic disorders (control group) who underwent BMR recession were included. Success rates, surgical responses, and the amount of preoperative and postoperative distance-near disparity were evaluated and compared between the groups.

RESULTS

The mean preoperative esodeviation was not different between the SCA and control groups (20 vs 17.3 prism diopters [PD], P = .214). However, patients with SCA showed significant undercorrection compared with controls 1 week postoperatively (4.8 vs 1.0 PD, P = .048) and at the final follow-up (6.8 vs 1.8 PD, P = .032). The surgical success rates for the SCA and control groups were 40% and 80%, respectively (P = .095). Patients with SCA demonstrated a significantly reduced surgical response compared with controls (3.15 vs 3.87 PD/mm, P = .004), and a greater amount of postoperative distance-near disparity than controls (8.0 vs 1.1 PD, P = .001).

CONCLUSIONS

A significant undercorrection was observed following BMR recession in esotropic patients with SCA. Accordingly, the authors recommend a slight overcorrection of 5 to 10 PD or adding a slanting procedure when planning strabismus surgery for this distinct group of patients. [J Pediatr Ophthalmol Strabismus. 2019;56(4):266-270.].

Vertical rectus muscle recession versus combined vertical and horizontal rectus muscle recession in patients with thyroid eye disease and hypotropia

PURPOSE

To compare the postoperative vertical drift in patients with thyroid eye disease (TED) with hypotropia who underwent vertical rectus recession alone versus vertical rectus recession combined with horizontal rectus recession.

METHODS

The medical records of patients with TED who underwent strabismus surgery for hypotropia between 2006 and 2015 were reviewed retrospectively. Patients were divided into two groups: group 1 underwent vertical rectus recession only; group 2 underwent vertical rectus recession plus horizontal rectus recession. Data collection included pre- and postoperative deviation measurements and amount of surgical recession performed. The amount of postoperative vertical drift between groups was compared.

RESULTS

Of 67 patients who underwent surgery during the study period, 18 met inclusion criteria, 9 in each group. Mean postoperative hypotropia was 24.2^Δ in group 1 and 24.5^Δ in group 2 (P = 0.82). Mean vertical deviations were 0.3^Δ and -2.2^Δ (P = 0.134) on postoperative day 1; -0.9^Δ and -8.0^Δ (P = 0.043) at final follow-up for groups 1 and 2. Mean postoperative vertical drift toward hypertropia was 1.2^Δ in group 1 and 6.8^Δ in group 2 (P = 0.048). The surgical success rate for group 1 was superior to that for group 2 (89% vs 67% [P = 0.024]).

CONCLUSIONS

There was a significantly larger postoperative vertical drift in TED patients with hypotropia who had combined vertical rectus and horizontal rectus recessions compared with those who underwent vertical rectus recession alone.

Quantitative analysis of optical coherence tomographic angiography (OCT-A) in patients with non-arteritic anterior ischemic optic neuropathy (NAION) corresponds to visual function

Purpose

Non-arteritic anterior ischemic optic neuropathy (NAION) is the most common cause of non-glaucomatous optic neuropathy in older adults. Optical coherence tomographic angiography (OCT-A) is an emerging, non-invasive method to study the microvasculature of the posterior pole, including the optic nerve head. The goal of this study was to assess the vascular changes in the optic nerve head and peripapillary area associated with NAION using OCT-A.

Design

Retrospective comparative case series.

Methods

We performed OCT-A in 25 eyes (7 acute and 18 non-acute) in 19 patients with NAION. Fellow, unaffected eyes were analyzed for comparison. Patent macro- and microvascular densities were quantified in the papillary and peripapillary regions of unaffected, acutely affected, and non-acutely affected eyes and compared across these groups according to laminar segment and capillary sampling region, and with respect to performance on automated visual field testing.

Results

In acutely affected eyes, OCT-A revealed a reduction in the signal from the major retinal vessels and dilation of patent superficial capillaries in the peripapillary area. By contrast, non-acutely affected eyes showed attenuation of patent capillaries. The peripapillary choriocapillaris was obscured by edema in acute cases, but was similar between non-acute and unaffected eyes. The degree of dilation of the superficial microvasculature in the acute phase and attenuation in the non-acute phase each correlated inversely with visual field performance. The region of reduced patent capillary density correlated with the location of visual field defects in 80% of acute cases and 80% of non-acute cases.

Conclusions

OCT-A reveals a dynamic shift in the superficial capillary network of the optic nerve head with strong functional correlates in both the acute and non-acute phases of NAION. Further study may validate OCT-A as a useful adjunctive diagnostic tool in the evaluation of ischemic optic neuropathy.

Orbital leiomyosarcoma metastasis presenting prior to diagnosis of the primary tumor

Leiomyosarcomas, neoplasms of smooth muscle, are rarely found within the orbit. Orbital leiomyosarcoma may be primary, metastatic, or secondary to radiation. When they are metastatic, patients almost exclusively have a history of a primary leiomyosarcoma, often occurring in the spermatic cord, skin, gastrointestinal tract, or the uterus. We present the case of 48-year-old woman who presented with a metastatic orbital leiomyosarcoma, which was identified before the primary tumor.

Optical coherence tomographic angiography identifies peripapillary microvascular dilation and focal non-perfusion in giant cell arteritis

AIMS

We set out to determine the optical coherence tomographic angiography (OCT-A) characteristics of arteritic anterior ischaemic optic neuropathy (AAION) in the context of giant cell arteritis (GCA).

METHODS

This is an observational case series of four patients with AAION secondary to GCA, three with unilateral AAION and one with bilateral AAION. We reviewed the charts, fundus photography, visual fields, fluorescein angiography (FA) and OCT-A images for all patients to identify a unifying theme in a range of AAION clinical severity. Imaging of two healthy control eyes from two patients of similar age to the patients in our series were used for comparison.

RESULTS

Superficial peripapillary capillary dilation was seen in eyes with acute AAION. It was also noted in the fellow eyes of two patients. Retinal capillary perfusion defects corresponded to visual field loss. Dense optic disc oedema and cotton-wool spots imparted blockage effects. OCT-A laminar analysis did not highlight the choroidal/choriocapillaris perfusion defects seen on FA in two patients. Follow-up OCT-A was obtained in two patients and revealed progression to superficial peripapillary capillary attenuation that corresponded with visual field loss.

CONCLUSIONS

There are acute and chronic vascular changes in AAION that are detectable by OCT-A that correspond with visual function. Though the microvascular changes seen in GCA and AAION are not specific, the nearly ubiquitous findings among preclinical and clinically affected eyes in this series of patients with GCA support OCT-A as a potentially useful adjunctive diagnostic test in the work-up of ambiguous cases of suspected ischaemic optic neuropathy.

Diplopia after Cataract Extraction

Diplopia after cataract extraction is an unexpected outcome for the patient and often a source of confusion for the physician, owing to its relative infrequency. This article reviews the pertinent literature on the subject. Mechanisms include anesthetic myotoxicity, surgical trauma, optical aberrations, cortical disorders in patients with congenital strabismus, and the unmasking of previously unnoticed ocular misalignment. As the population continues to age and cataract extraction is performed in increasing volume, familiarity with this uncommon but important outcome may help to clarify and effectively treat post-cataract-extraction diplopia.

Diagnostic genetic testing for patients with bilateral optic neuropathy and comparison of clinical features according to OPA1 mutation status

PURPOSE

Inherited optic neuropathy is genetically heterogeneous, and genetic testing has an important role in risk assessment and counseling. The purpose of this study is to determine the prevalence and spectrum of mutations in a group of patients referred for genetic testing to a tertiary center in the United States. In addition, we compared the clinical features of patients with and without mutations in OPA1, the gene most commonly involved in dominantly inherited optic atrophy.

METHODS

Clinical data and genetic testing results were reviewed for 74 unrelated, consecutive patients referred with a history of insidious, relatively symmetric, bilateral visual loss secondary to an optic neuropathy. Patients were evaluated for disease-causing variants in OPA1, OPA3, WFS1, and the entire mitochondrial genome with DNA sequencing and copy number variation (CNV) testing.

RESULTS

Pathogenic DNA variants were found in 25 cases, with the majority (24 patients) located in OPA1. Demographics, clinical history, and clinical features for the group of patients with mutations in OPA1 were compared to those without disease-causing variants. Compared to the patients without mutations, cases with mutations in OPA1 were more likely to have a family history of optic nerve disease (p = 0.027); however, 30.4% of patients without a family history of disease also had mutations in OPA1. OPA1 mutation carriers had less severe mean deviation and pattern standard deviation on automated visual field testing than patients with optic atrophy without mutations in OPA1 (p<0.005). Other demographic and ocular features were not statistically significantly different between the two groups, including the fraction of patients with central scotomas (42.9% of OPA1 mutation positive and 66.0% of OPA1 mutation negative).

CONCLUSIONS

Genetic testing identified disease-causing mutations in 34% of referred cases, with the majority of these in OPA1. Patients with mutations in OPA1 were more likely to have a family history of disease; however, 30.4% of patients without a family history were also found to have an OPA1 mutation. This observation, as well as similar frequencies of central scotomas in the groups with and without mutations in OPA1, underscores the need for genetic testing to establish an OPA1 genetic diagnosis.

Patterns of visual field changes in thyroid eye disease

This article provides a systematic description of visual field changes in thyroid eye disease-compressive optic neuropathy (TED-CON). A retrospective, non-comparative chart review of patients with TED-CON and documented Humphrey Visual Field 24-2 or 30-2 testing was conducted with IRB approval. Ninety-six visual fields in 68 patients were classified into 7 broad categories (superior, inferior, diffuse, temporal, nasal, central/paracentral, enlarged blind spot) and 17 mutually exclusive patterns from the Ocular Hypertension Treatment Study (OHTS) or "other." Fifty-three of 96 visual fields (55%) showed an inferior defect using the broad categories, with the remaining 6 categories ranging from 2% to 14%. The five most common OHTS patterns were other (28%), partial arcuate (28%), partial peripheral rim (9%), arcuate (8%) and altitudinal (7%). Further sub-classification showed a predominance of inferior visual field defects, ranging from 33% to 93% of each category. Of the 78 visual fields in these five categories combined, 52 (67%) were inferior defects. Inferior defect is the most typical TED-CON-associated visual field change. While the OHTS categories are geared toward classification of glaucomatous patterns, the overall predominance of inferior field defects in TED-CON was clearly demonstrated. These "other" visual field changes showing central inferior defect up to but not crossing the horizontal meridian and not contiguous from blind spot to nasal meridian should be designated as "TED-CON pattern." The high proportion of visual fields falling under the "other" category, however, does demonstrate the need for a more specific and tailored visual field classification system for TED-CON.

Clinical characteristics and long-term visual outcome of optic neuritis in neuromyelitis optica spectrum disorder: A comparison between Thai and American-Caucasian cohorts

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) occurs more commonly in Asian than Caucasian populations. Few studies have examined the clinical features and visual outcome of optic neuritis (ON) within NMOSD in different racial populations. The objective of this study was to compare the clinical characteristics and long-term visual outcome of a Thai and an American-Caucasian cohort with NMOSD-related ON.

METHODS

Medical records including brain and orbital magnetic resonance imaging (MRI) of 16 consecutive subjects who developed visual loss due to ON as part of NMOSD evaluated at a single American tertiary referral center between 2006 and 2015 were reviewed and compared to those of 16 consecutive similar subjects evaluated at a single Thai tertiary referral center between 2010 and 2016. These cohorts represented the total number of NMOSD-related ON subjects seen during that time at those institutions. Statistical analyses were used for continuous and categorical data sets, and multiple regression analysis was used to adjust for differences in duration of follow-up and number of episodes of ON in each affected eye.

RESULTS

All subjects within the Thai cohort were Asian, while the American cohort initially consisted of 14 Caucasian, 1 Asian and 1 African-American subject, but the latter two were excluded from analysis. In the Thai cohort, ON occurred in 21 eyes, with a total of 19 episodes, while in the American-Caucasian cohort ON occurred in 22 eyes, with a total of 21 episodes. Aquaporin 4 (AQP4)-antibody was positive in all subjects except for one American-Caucasian subject. The mean follow-up time was 17.8 (± 16.0) and 52.8 (± 51.9) months for the Thai and American-Caucasian populations, respectively. There was no difference between the two cohorts with respect to gender, age of NMOSD and NMOSD-related ON onset, initial clinical presentation of NMOSD, initial visual acuity and automated visual fields, prevalence of swollen optic disc in the acute phase, presence of pain on the affected side, mean time of onset of ON symptoms to MRI examination, distribution of segmental involvement of the anterior visual pathway abnormalities based on MRI findings, mean time of onset of ON symptoms to treatment, final visual acuity and automated visual fields. However, a higher proportion of Thai affected eyes were found to have an initial visual acuity of 20/200 or worse compared with the American-Caucasian cohort. Azathioprine was the most common maintenance treatment (75%) used among Thai subjects in contrast to rituximab (78.6%) among American-Caucasian subjects.

CONCLUSION

Despite the different prevalence among Thai and American-Caucasian populations, the clinical characteristics of ON in the NMOSD were very similar across these two populations, other than for more severe visual loss initially among Thai subjects. Notably, long-term visual outcome did not differ between these cohorts despite significant difference in the maintenance treatment regimen. This study did not assess neurological status or outcome.

Isolated presumed optic nerve gumma, a rare presentation of neurosyphilis

Purpose

The incidence of syphilitic infections continues to rise and represents a major public health concern, particularly in patients co-infected with human immunodeficiency virus (HIV). The infection has a multitude of clinical presentations and is often referred to as the 'great imitator.' We present a rare case of an isolated presumed syphilitic optic nerve gumma and characterize it using newer imaging modalities.

Observations

A 36-year-old HIV-positive man, compliant with treatment, presented with a five day history of decreased vision in the left eye. On examination his visual acuity was 20/30 with mild dyschromatopsia and an inferior altitudinal field defect in the left eye. Funduscopy demonstrated small cup to disc ratios bilaterally and a swollen and hyperemic left optic disc. Following five months of stable vision, the patient's vision in the left eye declined to 20/60, associated with diffuse visual field loss and continued swelling of the left optic disc. Subsequent magnetic resonance imaging with contrast demonstrated enhancement of the left optic nerve, and his serologies were positive for syphilis. Fluorescein angiography and optical coherence tomography were used to better characterize the lesion being most consistent with a syphilitic optic nerve gumma.

Conclusions and importance

Gummas of the central nervous system are a rare presentation of neurosyphilis and the last reported gumma of the optic nerve was in 1990. Such lesions have not been characterized using newer imaging modalities including optical coherence tomography and fluorescein angiography, both of which may assist in the diagnosis of this rare entity. With the increased prevalence of syphilis and remarkable response to therapy, syphilitic gummas should be considered in at-risk patients presenting with an optic neuropathy.

Leber Hereditary Optic Neuropathy: Bringing the Lab to the Clinic

Leber hereditary optic neuropathy (LHON) was the first clinically characterized mitochondrial disorder. Since its first description in 1871, much has been discovered regarding the genetics and pathophysiology of the disease. This has enabled the development of in vitro cell and animal models that can be used to try to determine not only the effects of the genetic mutation upon the clinical phenotype but to also test potential novel therapies. Treatments for LHON have ranged from vitamins and minerals to immunosuppressants and, more recently, targeted gene therapy. This article reviews the pathophysiology and clinical features of LHON with a focus on translational research.

Demographic, Systemic, and Ocular Factors Associated with Nonarteritic Anterior Ischemic Optic Neuropathy

OBJECTIVE

Nonarteritic anterior ischemic optic neuropathy (NAION) is a devastating ocular condition causing permanent vision loss. Little is known about risk factors for developing this disease. We assessed demographic, systemic, and ocular factors associated with NAION.

DESIGN

Retrospective longitudinal cohort study.

PARTICIPANTS

Beneficiaries between 40 and 75 years old without NAION at baseline enrolled in a large U.S. managed care network.

METHODS

Enrollees were monitored continuously for ≥2 years between 2001 and 2014 to identify those newly diagnosed with NAION (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] code 377.41). All persons were under ophthalmic surveillance and all cases had ≥1 confirmatory ICD-9-CM code for NAION during follow-up.

MAIN OUTCOME MEASURES

Multivariable Cox regression modeling was used to generate hazard ratios (HRs) with 95% confidence intervals (CIs) to describe the statistical relationship between selected demographic characteristics, systemic and ocular conditions, and the hazard of developing NAION.

RESULTS

Of 1 381 477 eligible enrollees, 977 (0.1%) developed NAION during a mean ± standard deviation (SD) follow-up of 7.8±3.1 years. The mean ± SD age for NAION cases at the index date was 64.0±9.2 years vs. 58.4±9.4 years for the remainder of the beneficiaries. After adjustment for confounding factors, each additional year older was associated with a 2% increased hazard of NAION (HR = 1.02; 95% CI: 1.01-1.03). Female subjects had a 36% decreased hazard of developing NAION (HR = 0.64; 95% CI: 0.55-0.74) compared with male subjects. Compared with whites, Latinos had a 46% decreased hazard of developing NAION (HR = 0.54; 95% CI: 0.36-0.82), whereas African ancestry was not significantly associated with NAION (HR = 0.91; 95% CI: 0.72-1.15). Systemic diseases associated with NAION included hypertension (HR = 1.62; 95% CI: 1.26-2.07) and hypercoagulable states (HR = 2.46; 95% CI: 1.51-4.00). Although diabetes mellitus (DM) was not significantly associated with NAION compared with those without DM (P = 0.45), patients with end-organ involvement from DM had a 27% increased hazard of NAION relative to those with uncomplicated DM (HR = 1.27; 95% CI: 1.01-1.59). Ocular diseases associated with NAION were age-related macular degeneration (HR = 1.29; 95% CI: 1.08-1.54) and retinal vein occlusion (HR = 3.94; 95% CI: 3.11-4.99).

CONCLUSIONS

Our study identified several modifiable risk factors that may be associated with NAION. Should future studies confirm these findings, they may offer opportunities to prevent or treat this debilitating condition.

Radiation optic neuropathy and retinopathy with low dose (20 Gy) radiation treatment

Purpose

To report a case of optic neuropathy and retinopathy from a dose of radiation traditionally thought to be safe to the visual system and discuss strategies for preventing vision loss when using radiation to treat intraocular tumors.

Observations

A 44-year-old woman presented with new, painless vision loss in the left eye eighteen months after receiving proton beam radiotherapy (20 Gy dose delivered in two 10 Gy fractions) for a uveal metastasis of lung cancer. The dilated funduscopic examination revealed optic disc swelling and retinal hemorrhages and an MRI of the brain and orbits demonstrated enhancement of the left optic nerve head, findings consistent with radiation optic neuropathy (RON) and retinopathy. Risk factors for developing RON included coincident use of oral chemotherapy and relatively large fractionated doses of radiation.

Conclusions and importance

Though cumulative radiation doses to the anterior visual pathway of less than 50 Gy are traditionally felt to be safe, it is important to consider not just the total exposure but also the size of individual fractions. The single-dose threshold for RON in proton beam treatment has yet to be defined. Our case suggests that fractions of less than 10 Gy should be delivered to minimize the risk of optic nerve injury.

Migraine photophobia originating in cone-driven retinal pathways

Migraine headache is uniquely exacerbated by light. Using psychophysical assessments in patients with normal eyesight we found that green light exacerbates migraine headache significantly less than white, blue, amber or red lights. To delineate mechanisms, we used electroretinography and visual evoked potential recording in patients, and multi-unit recording of dura- and light-sensitive thalamic neurons in rats to show that green activates cone-driven retinal pathways to a lesser extent than white, blue and red; that thalamic neurons are most responsive to blue and least responsive to green; and that cortical responses to green are significantly smaller than those generated by blue, amber and red lights. These findings suggest that patients' experience with colour and migraine photophobia could originate in cone-driven retinal pathways, fine-tuned in relay thalamic neurons outside the main visual pathway, and preserved by the cortex. Additionally, the findings provide substrate for the soothing effects of green light.

An Experimental Animal Model of Photodynamic Optic Nerve Head Injury (PONHI)

PURPOSE

Anterior ischemic optic neuropathy (AION) is the most common cause of non-glaucomatous optic nerve head (ONH) injury among older adults. AION results from a sudden ischemic insult to the proximal portion of the optic nerve, typically leading to visual impairment. Here, we present an experimental model of photodynamically induced ONH injury that can be used to study neuroprotective modalities.

METHODS

Intraperitoneal injection of mesoporphyrin IX was followed by photodynamic treatment of the ONH in one eye of Brown-Norway rats; the fellow eye received the reverse sequence as a sham control. Fluorescein angiography (FA), spectral domain optical coherence tomography (SD-OCT), and visual evoked potential (VEP) recordings were performed at different time points following laser treatment. Immunohistochemistry was used to monitor apoptotic cell death (TUNEL) and macrophage infiltration (CD68). Cytokine levels were evaluated using enzyme-linked immunosorbent assay (ELISA).

RESULTS

FA showed early hyperfluorescence and late leakage of the ONH, while SD-OCT revealed optic nerve edema. No leakage or other abnormalities were detected in control eyes. VEPs were significantly reduced in amplitude and showed prolonged responses compared to sham eyes. The number of apoptotic retinal ganglion cells was elevated one day after laser treatment (13.77 ± 4.49, p < 0.01) and peaked on day 7 (57.22 ± 11.34, p < 0.01). ONH macrophage infiltration also peaked on day 7 (101.8 ± 9.8, p < 0.05). ELISAs performed showed upregulation of macrophage chemoattractant protein-1 and macrophage inflammatory protein-2 on days 3 and 1, respectively.

CONCLUSIONS

Photodynamic treatment of the ONH after administration of mesoporphyrin IX leads to macroscopic, histologic, and physiologic evidence of ONH injury. Given the long half-life of mesoporphyrin IX and the ease of intraperitoneal injections, this new model of photodynamically induced ONH injury may be a useful tool for studying optic nerve injury and possible neuroprotective treatments.

Optic neuropathy following retrobulbar injection: a review

A retrobulbar block is a regional anesthetic nerve block in the retrobulbar space. Optic neuropathy following retrobulbar injection is a well-recognized and rare complication of the procedure with an unknown incidence. This article reviews the relevant literature regarding vision loss following this procedure. Mechanisms of injury to the optic nerve as well as methods that can be employed to minimize the risk of optic neuropathy will be explored, including alternatives to retrobulbar anesthesia.

A Rod-Sparing Retinopathy in Bardet-Biedl Syndrome

Bardet-Biedl syndrome is a continuum of disorders characterized by systemic and ocular findings. Retinal abnormalities typically present as diffuse photoreceptor degeneration. Here, we report a novel case that suggests a rod-sparing variant of Bardet-Biedl syndrome.

Ocular flutter as the presenting sign of lung adenocarcinoma

Ocular flutter is a rare ophthalmic finding that could represent paraneoplastic phenomena. In adults it is most commonly associated with small cell lung cancer (SCLC). Most patients also present with other neurological defects. We report the case of a 75-year-old woman who presented with isolated ocular flutter. The ensuing workup was significant for an early lung adenocarcinoma that would not have been biopsied otherwise due to its small size. To our knowledge, this is the first reported case of isolated ocular flutter as the presenting symptom of non-SCLC.

Deprivation amblyopia and congenital hereditary cataract

Amblyopia is a neurodevelopmental disorder of vision associated with decreased visual acuity, poor or absent stereopsis, and suppression of information from one eye.(1,2) Amblyopia may be caused by strabismus (strabismic amblyopia), refractive error (anisometropic amblyopia), or deprivation from obstructed vision (deprivation amblyopia). 1 In the developed world, amblyopia is the most common cause of childhood visual impairment, 3 which reduces quality of life 4 and also almost doubles the lifetime risk of legal blindness.(5, 6) Successful treatment of amblyopia greatly depends on early detection and treatment of predisposing disorders such as congenital cataract, which is the most common cause of deprivational amblyopia. Understanding the genetic causes of congenital cataract leads to more effective screening tests, early detection and treatment of infants and children who are at high risk for hereditary congenital cataract.

The use of fourth-generation optical coherence tomography in multiple sclerosis: a review

Optical coherence tomography (OCT) has been routinely used to obtain high spatial resolution images of the retina and choroid non-invasively. Within the past decade, a fourth-generation OCT device using Fourier domain (FD) analysis has been developed that provides higher velocity and higher axial resolution images with better reproducibility than the previous generation time domain (TD) OCT technology. This review addresses the use of fourth-generation, FD ocular OCT in patients with multiple sclerosis.

Neuro-imaging: a review for the general ophthalmologist

The diagnosis of many neuro-ophthalmic conditions is facilitated with neuro-imaging. The two main modalities are Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). Clinicians who refer patients for either of these techniques must not only know which of them to choose, but also where the imaging should be performed (e.g. brain, orbit), whether or not contrast is indicated, and if angiography should be supplemented. These complexities often result in imaging studies that are either unneeded or unhelpful. The goal of this manuscript is to provide a practical set of guidelines for the general ophthalmologist of how to choose the correct parameters for neuro-imaging studies.

Concurrent acute brain infarcts in patients with monocular visual loss

OBJECTIVE

Embolism from a proximal source to the retinal circulation could be a sign of embolism from the same source to the hemispheric circulation. We sought to determine the frequency of acute brain infarcts on diffusion-weighted imaging (DWI) in patients with monocular visual loss of presumed ischemic origin (MVL).

METHODS

We retrospectively studied 129 consecutive patients with MVL secondary to retinal ischemia. All patients underwent DWI, comprehensive ophthalmologic and neurologic examination, and diagnostic evaluations for the underlying etiology. Statistical analyses explored univariate and multivariate predictors of DWI evidence of acute brain infarcts.

RESULTS

DWI revealed concurrent acute brain infarct(s) in 31 of the 129 patients (24%). The probability of positive DWI was higher in embolic versus nonembolic MVL (28 vs 8%, p = 0.04), in MVL characterized by permanent visual loss versus transient symptoms (33 vs 18%, p = 0.04), and in MVL associated with concurrent hemispheric symptoms versus isolated MVL (53 vs 20%, p < 0.01). Patients with positive DWI were more likely to harbor a major underlying etiology as compared to those with normal DWI (odds ratio, 3.7; 95% confidence interval, 1.5-9.4).

INTERPRETATION

This study demonstrates that MVL does not always represent an isolated disease of the retina; approximately 1 of every 4 patients with MVL demonstrates acute brain infarcts on DWI. Because patients with concurrent brain infarcts are more likely to exhibit a cardiac or vascular source of embolism, imaging evidence of brain injury in patients with MVL may be a useful marker to guide the timing and extent of diagnostic examinations.

Decreased vision and junctional scotoma from pituicytoma

Pituicytomas are rare neoplasms of the sellar region. We report a case of vision loss and a junctional scotoma in a 43-year-old woman caused by compression of the optic chiasm by a pituitary tumor. The morphological and immunohistochemical characteristics of the tumor were consistent with the diagnosis of pituicytoma. The tumor was debulked surgically, and the patient's vision improved.

Isolated bilateral fourth cranial nerve palsies as the presenting sign of hydrocephalus

Midbrain lesions leading to bilateral fourth nerve palsies are typically accompanied by other brainstem symptomatology. Here we report a case of a 29-year-old man with hydrocephalus and significant third ventricle dilation applying pressure on the dorsal midbrain and having as only manifestation isolated, bilateral fourth cranial nerve palsies. This finding, reported now for the first time, could be attributed to a partially working ventriculoperitoneal shunt previously placed to this patient, which was able to sporadically relieve the increases of the intraventricular pressure on the midbrain that would normally lead to other manifestations.

The use of onabotulinum toxin A in the treatment of see-saw nystagmus

See-saw nystagmus (SSN) is an uncommon disorder that consists of cycles in which one eye rises and intorts while the other depresses and extorts, followed by reversal of the pattern. It typically causes debilitating symptoms including oscillopsia that interfere with activities of daily living. There are myriad etiologies, including stroke, tumors, trauma, and multiple sclerosis. Treatment options are limited and are often unsatisfactory. The authors report a case in which targeted injections of onabotulinum toxin A were used to decrease the torsional component of SSN and thus significantly improve the subjective symptoms of oscillopsia in a patient with acquired SSN.

Recurrent isolated sixth nerve palsy after consecutive annual influenza vaccinations in a child

Recurrent sixth nerve palsy in children in the absence of structural or other neurological abnormality is a rare occurrence. We report the case of recurrent isolated sixth (abducens) nerve palsy after consecutive annual influenza vaccinations in an otherwise-healthy 2-year-old boy. Investigations including magnetic resonance imaging of the brain and orbits after each episode failed to reveal any abnormality. The temporal relation to the immunizations supports but does not prove that the influenza immunization regimen was responsible.