Modulation of sensory photophobia in essential blepharospasm with chromatic lenses

Progressive thalamic nuclear atrophy in blepharospasm and blepharospasm-oromandibular dystonia

The thalamus is considered a key region in the neuromechanisms of blepharospasm. However, previous studies considered it as a single, homogeneous structure, disregarding potentially useful information about distinct thalamic nuclei. Herein, we aimed to examine (i) whether grey matter volume differs across thalamic subregions/nuclei in patients with blepharospasm and blepharospasm-oromandibular dystonia; (ii) causal relationships among abnormal thalamic nuclei; and (iii) whether these abnormal features can be used as neuroimaging biomarkers to distinguish patients with blepharospasm from blepharospasm-oromandibular dystonia and those with dystonia from healthy controls. Structural MRI data were collected from 56 patients with blepharospasm, 20 with blepharospasm-oromandibular dystonia and 58 healthy controls. Differences in thalamic nuclei volumes between groups and their relationships to clinical information were analysed in patients with dystonia. Granger causality analysis was employed to explore the causal effects among abnormal thalamic nuclei. Support vector machines were used to test whether these abnormal features could distinguish patients with different forms of dystonia and those with dystonia from healthy controls. Compared with healthy controls, patients with blepharospasm exhibited reduced grey matter volume in the lateral geniculate and pulvinar inferior nuclei, whereas those with blepharospasm-oromandibular dystonia showed decreased grey matter volume in the ventral anterior and ventral lateral anterior nuclei. Atrophy in the pulvinar inferior nucleus in blepharospasm patients and in the ventral lateral anterior nucleus in blepharospasm-oromandibular dystonia patients was negatively correlated with clinical severity and disease duration, respectively. The proposed machine learning scheme yielded a high accuracy in distinguishing blepharospasm patients from healthy controls (accuracy: 0.89), blepharospasm-oromandibular dystonia patients from healthy controls (accuracy: 0.82) and blepharospasm from blepharospasm-oromandibular dystonia patients (accuracy: 0.94). Most importantly, Granger causality analysis revealed that a progressive driving pathway from pulvinar inferior nuclear atrophy extends to lateral geniculate nuclear atrophy and then to ventral lateral anterior nuclear atrophy with increasing clinical severity in patients with blepharospasm. These findings suggest that the pulvinar inferior nucleus in the thalamus is the focal origin of blepharospasm, extending to pulvinar inferior nuclear atrophy and subsequently extending to the ventral lateral anterior nucleus causing involuntary lower facial and masticatory movements known as blepharospasm-oromandibular dystonia. Moreover, our results also provide potential targets for neuromodulation especially deep brain stimulation in patients with blepharospasm and blepharospasm-oromandibular dystonia.

FL-41 Tint Reduces Activation of Neural Pathways of Photophobia in Patients with Chronic Ocular Pain

PURPOSE

To assess the therapeutic effect of tinted lenses (FL-41) on photophobia and light-evoked brain activity using functional magnetic resonance imaging (fMRI) in individuals with chronic ocular surface pain.

DESIGN

Prospective case series.

METHODS

25 subjects from the Miami veterans affairs (VA) eye clinic were recruited based on the presence of chronic ocular pain, dry eye symptoms, and photophobia. Using a 3T MRI scanner, subjects underwent 2 fMRI scans using an event-related design based on light stimuli: one scan while wearing FL-41 lenses and one without. Unpleasantness ratings evoked by the light stimuli were collected after each scan.

RESULTS

With FL-41 lenses, subjects reported decreased (n = 19), maintained (n = 2), or increased (n = 4) light-evoked unpleasantness ratings. Group analysis at baseline (no lens) revealed significant light evoked responses in bilateral primary somatosensory (S1), bilateral secondary somatosensory (S2), bilateral insula, bilateral frontal pole, visual, precuneus, paracingulate, and anterior cingulate cortices (ACC) as well as cerebellar vermis, bilateral cerebellar hemispheric lobule VI, and bilateral cerebellar crus I and II. With FL-41 lenses, light-evoked responses were significantly decreased in bilateral S1, bilateral S2, bilateral insular, right temporal pole, precuneus, ACC, and paracingulate cortices as well as bilateral cerebellar hemispheric lobule VI.

CONCLUSION

FL-41 lenses modulated photophobia symptoms in some individuals with chronic ocular pain. In conjunction, FL-41 lenses decreased activation in cortical areas involved in processing affective and sensory-discriminative dimensions of pain. Further research into these relationships will advance the ability to provide precision therapy for individuals with ocular pain.

Cannabidiol as an Adjunct to Botulinum Toxin in Blepharospasm - A Randomized Pilot Study

Purpose

The purpose of this study was to evaluate the safety and efficacy of low dose cannabidiol (CBD; Epidiolex) as adjunctive therapy for idiopathic adult-onset blepharospasm (BPS), as well as develop a novel objective assessment methodology to gauge response.

Methods

Prospective, randomized, double-masked, placebo-controlled crossover design of 6 months duration of 12 patients with BPS undergoing routine maximal botulinum toxin (BTX) therapy and experiencing breakthrough symptoms. Participants received their standard BTX every 3 months and were randomized to group A = CBD daily in cycle 1, followed by placebo in cycle 2 or group B = placebo followed by CBD. Videos recorded at days 0, 45, and 90 of each cycle were analyzed to quantify eyelid kinematics. The Jankovic Rating Scale (JRS) was used to provide a clinical rating.

Results

All 12 patients completed the study without adverse events. CBD decreased median eyelid closure amplitude by 19.1% (-1.66 mm, confidence interval [CI] = -3.19 to -0.14 mm, P = 0.03), decreased median eyelid closure duration by 15.8% (-18.35 ms, CI = -29.37 to -7.32 ms, P = 0.001), and increased the maximum eyelid closure velocity by 34.8% (-13.26 mm/ms, CI = -20.93 to -5.58 mm/ms, P = 0.001). The JRS showed a 0.5 reduction in severity and frequency, which was not statistically significant.

Conclusions

Low dose CBD was safely tolerated and improved several BPS kinematic parameters. The clinical scale suggested a direction of effect but may have been underpowered. Further studies are needed to better quantify the clinical relevance.

Translational Relevance

This work describes a novel assessment methodology and therapeutic approach to bBPS.

Application of colored filters in patients post-traumatic brain injury: A review

BACKGROUND: Tinted lenses have been used to manage visual discomfort and photosensitivity in patients with migraines, benign essential blepharospasm (BEB) and epilepsy. OBJECTIVES: The purpose of this review is to examine the existing clinical research regarding the use of colored filters among patients recovering from traumatic brain injuries. METHODS: A review of English articles from PubMed, Embase from embase.com, Web of Science, APA PsycINFO (OVID), Scopus, and Cochrane Central Register of Controlled Trials with publication years from date of inception to June 10, 2021 was performed. Articles were first screened by title and abstract, followed by full-text review. The search strategy resulted in 7819 results. The final analysis included seven articles which discussed the use of tinted lenses in patients post-traumatic brain injury. RESULTS: While there is a paucity of information related to the therapeutic use of tinted lenses to mitigate post-traumatic light sensitivity and migraines, patients will subjectively report improved symptoms, specifically with precision tints or FL-41. CONCLUSION: Further studies are needed to understand the mechanism of action as well as objective and subjective benefits of tinted lenses in patient post-traumatic brain injury.

Photoaversion in inherited retinal diseases: clinical phenotypes, biological basis, and qualitative and quantitative assessment

Severe light sensitivity is a feature common to a range of ophthalmological and neurological diseases. In inherited retinal diseases (IRDs) particularly, this may be accompanied by significant visual disruption. These symptoms are extremely debilitating for affected individuals and have significant implications in terms of day-to-day activities. Underlying mechanisms remain to be fully elucidated. Currently, there are many assessments of photoaversion (PA), however, all have limitations, with quantitative measurement in particular needing further evaluation. To understand the complexities associated with photoaversion from different pathologies, qualitative and quantitative assessments of the light aversion response must be standardized. There is no treatment to date, and strategies to alleviate symptoms focus on light avoidance. With respect to IRDs, however, gene therapy is currently being investigated in clinical trials and promising and further treatments may be on the horizon. The better characterization of these symptoms is an important end point measure in IRD gene therapy trials.

Visual and non-visual properties of filters manipulating short-wavelength light

Purpose

Optical filters and tints manipulating short‐wavelength light (sometimes called ‘blue‐blocking’ or ‘blue‐attenuating’ filters) are used in the management of a range of ocular, retinal, neurological and psychiatric disorders. In many cases, the only available quantification of the optical effects of a given optical filter is the spectral transmittance, which specifies the amount of light transmitted as a function of wavelength.

Methods

We propose a novel physiologically relevant and retinally referenced framework for quantifying the visual and non‐visual effects of these filters, incorporating the attenuation of luminance (luminous transmittance), the attenuation of melanopsin activation (melanopsin transmittance), the colour shift, and the reduction of the colour gamut (gamut reduction). Using these criteria, we examined a novel database of spectral transmittance functions of optical filters (n = 121) which were digitally extracted from a variety of sources.

Results

We find a large diversity in the alteration of visual and non‐visual properties. The spectral transmittance properties of the examined filters vary widely, in terms of shapes and cut‐off wavelengths. All filters show relatively more melanopsin attenuation than luminance attenuation (lower melanopsin transmittance than luminous transmittance). Across the data set, we find that melanopsin transmittance and luminous transmittance are correlated.

Conclusions

We suggest that future studies and examinations of the physiological effects of optical filters quantify the visual and non‐visual effects of the filters beyond the spectral transmittance, which will eventually aid in developing a mechanistic understanding of how different filters affect physiology. We strongly discourage comparing the downstream effects of different filters on, e.g. sleep or circadian responses, without considering their effects on the retinal stimulus.

Effect of light on blinking in patients with idiopathic isolated blepharospasm

OBJECTIVE

Melanopsin may be involved in the pathophysiology of photophobia in idiopathic isolated blepharospasm. We assessed the efficacy of blocking wavelengths of melanopsin absorption to reduce blinking in blepharospasm as a possible surrogate for photophobia.

METHODS

Twenty-one participants (11 blepharospasm and 10 healthy controls) were studied. There were three sessions: (1) a baseline condition to measure the blink rate (BR) without intervention; (2) two conditions where the participants received intermittent light stimuli with high or low intensity without wearing study lenses; (3) four conditions in which the participants received intermittent light stimuli with high intensity while wearing one of four different lenses: tinted lenses with neutral gray or FL-41, or coated lenses that block 480-nm or 590-nm wavelength. The primary outcome measure was the BR.

RESULTS

The blepharospasm group blinked more frequently than controls in dim room conditions. Patients reported greater photosensitivity compared to controls based on the questionnaire and exhibited a higher BR with intermittent light stimuli. The BR decreased for both groups when using 480-nm and 590-nm blocking lenses. In the patients, 480-nm and 590-nm blocking lenses reduced the mean BR by 9.6 blink/min and 10.3 blink/min, respectively, while in the control group, the mean BR decreased by 4.4 blink/min and 4.3 blink/min, respectively.

CONCLUSIONS

Blepharospasm patients had increased BR with light stimuli which decreased with 590-nm and 480-nm blocking lenses. The 480-nm- and 590-nm- coated lenses might have therapeutic potential in treating photophobia although BR does not appear to be an optimal biomarker for photophobia.

Pigmented contact lenses for managing ocular disorders

Blocking a selected wavelength range from the light spectrum can have multiple benefits. Ultra-violet (UV) radiation is detrimental to the retina, necessitating its blocking through sunglasses and contact lenses. The near-visible light also has enough energy to cause damage but, is typically not blocked by commercial lenses. Filtering light can also be useful to patients with migraines, amblyopia, and color blindness. Here, to achieve blocking, incorporation of pigments extracted from colored agro-products into contact lenses is explored. Pigment extraction from food powders including turmeric, spinach, paprika, and woad powders in ethanol is demonstrated. Lens immersion in pigment concentrated ethanol is done to facilitate swelling, allowing rapid pigment uptake. Pigment incorporation ensures the absence of visible light scattering, lens opacity, and leaching. The characterization of pigmented lenses is done through absorptivity and transmittance measurements. Degradation measurements investigate the stability of the green pigment extract from spinach powder with time. p-HEMA and silicone hydrogels loaded with >400 µg/g turmeric pigment act as class 1 UV blockers retaining >90% visible light transparency and screening >95% of the UVR spectra. Spinach, paprika, and woad powder loaded silicone lenses mitigate >20% visible light transmission from selective wavelengths finding applications in photophobia, amblyopia treatment, and color vision deficiency management.

Developments in the treatment of benign essential blepharospasm

PURPOSE OF REVIEW

To review new developments in the medical and surgical treatment options for benign essential blepharospasm (BEB).

RECENT FINDINGS

Botulinum toxin injections remain the mainstay treatment for BEB with several formulations currently commercially available. Reports in the medical literature support photochromatic modulation for the symptoms of photophobia, as well as oral medications and surgical myectomy for control of the motor signs of eyelid protractor spasm.

SUMMARY

Although there remains no cure for BEB, several treatment options are available to effectively manage the signs and symptoms of the condition.

Blepharospasm in Japan: A Clinical Observational Study From a Large Referral Hospital in Tokyo

Focal dystonia is regarded as a characteristic feature of blepharospasm. However, patients do not always present with motor symptoms. To clarify the clinical features of blepharospasm in Japan, we conducted a retrospective observational study involving a large population of patients from a single institution. Common symptoms included difficulty opening the eyes, photophobia, and ocular pain/irritation. Initial symptoms often occurred following the long-term use of psychotropics such as etizoram, benzodiazepines, and zolpidem (32% of patients). Our findings demonstrated that the clinical presentation of blepharospasm is heterogenous, and that understanding regarding sensory-dominant forms of the disease may be poor among practitioners in Japan.

Photophobia in neurologic disorders

Photophobia is a common symptom seen in many neurologic disorders, however, its pathophysiology remains unclear. Even the term is ambiguous. In this paper, we review the epidemiology and clinical manifestations of photophobia in neurological disorders, including primary headache, blepharospasm, progressive supranuclear palsy, and traumatic brain injury, discuss the definition, etiology and pathogenesis, and summarize practical methods of diagnosis and treatment.

Blepharospasm 40 years later

Forty years ago, C.D. Marsden proposed that blepharospasm should be considered a form of adult-onset focal dystonia. In the present paper, we provide a comprehensive overview of the findings regarding blepharospasm reported in the past 40 years. Although prolonged spasms of the orbicularis oculi muscles remain the clinical hallmark of blepharospasm, patients with blepharospasm may be characterized by various types of involuntary activation of periocular muscles. In addition to motor features, blepharospasm patients may also have nonmotor manifestations, including psychiatric, mild cognitive, and sensory disturbances. The various motor and nonmotor symptoms are not present in all patients, suggesting that blepharospasm is phenomenologically a heterogeneous condition. This emphasizes the need for tools for severity assessment that take into account both motor and nonmotor manifestations. The cause of blepharospasm remains elusive, but several lines of evidence indicate that blepharospasm is a multifactorial condition in which one, or several, as yet unknown genes together with epigenetic and environmental factors combine to reach the threshold of the disease. Although blepharospasm was originally believed to be solely a basal ganglia disorder, neurophysiological and neuroimaging evidence point to anatomical and functional involvement of several brain regions. The contribution of multiple areas has led to the hypothesis that blepharospasm should be considered as a network disorder, and this might reflect the varying occurrence of motor and nonmotor manifestations in blepharospasm patients. Despite advances in the aetiology and pathophysiology, treatment remains symptomatic. © 2017 International Parkinson and Movement Disorder Society.

Effect of chromatic filters on visual performance in individuals with mild traumatic brain injury (mTBI): A pilot study

PURPOSE

Spectral filters have been used clinically in patients with mild traumatic brain injury (mTBI). However, they have not been formally assessed using objective techniques in this population. Thus, the aim of the present pilot study was to determine the effect of spectral filters on reading performance and visuo-cortical responsivity in adults with mTBI.

METHODS

12 adults with mTBI/concussion were tested. All reported photosensitivity and reading problems. They were compared to 12 visually-normal, asymptomatic adults. There were several test conditions: three luminance-matched control filters (gray neutral density, blue, and red), the patient-selected 'precision tint lens' that provided the most comfort and clarity of text using the Intuitive Colorimeter System, and baseline without any filters. The Visagraph was used to assess reading eye movements and reading speed objectively with each filter. In addition, both the amplitude and latency of the visual-evoked potential (VEP) were assessed with the same filters.

RESULTS

There were few significant group differences in either the reading-related parameters or VEP latency for any of the test filter conditions. Subjective improvements were noted in most with mTBI (11/12).

CONCLUSIONS

The majority of patients with mTBI chose a tinted filter that resulted in increased visual comfort. While significant findings based on the objective testing were found for some conditions, the subjective results suggest that precision tints should be considered as an adjunctive treatment in patients with mTBI and photosensitivity.

An experimental study of the neurophysical mechanisms of photophobia induced by subarachnoid hemorrhage

BACKGROUND

Photophobia is defined as a painful psychosomatic discomfort triggered by intense light flow through the pupils to the brain, but the exact mechanism through which photophobia is induced by subarachnoid hemorrhage (SAH) is not well understood. In this study, we aimed to investigate whether there was any relationship between the mydriasis induced by the degeneration of the ciliary ganglion (CG) and photophobia in instances of SAH.

MATERIALS AND METHODS

Five of a total of 25 rabbits were used as the intact control group; five were used in the sham-operated control group; and the remaining 15 were used as the SAH group, which was created by injecting autologous blood into their cisterna magna. All animals were examined daily for 20days to evaluate their level of photophobia, after which their brains, CGs and superior cervical ganglia (SCGs) were extracted bilaterally. The densities of normal and degenerated neurons in these ganglia were examined by stereological methods.

RESULTS

In SAH animals with a high photophobia score, the mean pupil diameter and density of degenerated neurons density in the CG were greater than in cases with a low photophobia score (p<0.05). Further analysis revealed that the increase in the density of degenerated neurons in the CG following SAH resulted in the paralysis of the parasympathetic pathway of the pupillary muscles and mydriasis, which facilitates the excessive transfer of light to the brain and photophobia.

CONCLUSION

Our findings indicate that SAH results in a high density of degenerated neurons in the CG, which induces mydriasis and is an important factor in the onset of photophobia. This phenomenon is likely due to more light energy being transferred through mydriatic pupils to the brain, resulting in vasospasm of the supplying arteries.

Altered regional spontaneous neuronal activity in blepharospasm: a resting state fMRI study

The resting state amplitude of low-frequency fluctuations (ALFF) in functional magnetic resonance imaging (fMRI) is believed to reflect spontaneous cerebral neural activity. The pathophysiology of blepharospasm (BSP), which is characterized by motor symptoms and also sensory symptoms, remains unclear. The present study aims to localize possible cerebral functional abnormalities in BSP patients using resting state fMRI, and explore their possible associations with clinical variables. Voxel-based analysis was used to characterize the difference of ALFF between eighteen BSP patients and eighteen matched healthy controls. Separate correlation analyses were conducted to explore the possible association between ALFF values of significantly different areas and clinical measures including onset age, disease duration, symptom severity evaluated by Jankovic rating scale (JRS), and presence of geste antagoniste. The whole-brain analysis indicated that the BSP group had significantly decreased ALFF in the left thalamus while increased ALFF in the left orbitofrontal areas extending from middle frontal gyrus to inferior frontal gyrus. The mean ALFF in the left thalamus was negatively correlated with the subscore of JRS-frequency (r = -0.484, p = 0.042) and JRS total score (r = -0.477, p = 0.045). A borderline positive correlation was detected between the mean ALFF in the left orbitofrontal area and disease duration(r = 0.485, p = 0.049). Our findings suggest sensorimotor integration is abnormal in BSP, and dysfunctional activity of thalamus may be used to measuring symptom severity in BSP patients.

The focal dystonias: current views and challenges for future research

The most common forms of dystonia are those that develop in adults and affect a relatively isolated region of the body. Although these adult-onset focal dystonias are most prevalent, knowledge of their etiologies and pathogenesis has lagged behind some of the rarer generalized dystonias, in which the identification of genetic defects has facilitated both basic and clinical research. This summary provides a brief review of the clinical manifestations of the adult-onset focal dystonias, focusing attention on less well understood clinical manifestations that need further study. It also provides a simple conceptual model for the similarities and differences among the different adult-onset focal dystonias as a rationale for lumping them together as a class of disorders while at the same time splitting them into subtypes. The concluding section outlines some of the most important research questions for the future. Answers to these questions are critical for advancing our understanding of this group of disorders and for developing novel therapeutics.

Review and update of involuntary facial movement disorders presenting in the ophthalmological setting

We review the existing literature on the involuntary facial movement disorders-benign essential blepharospasm, apraxia of eyelid opening, hemifacial spasm, and aberrant facial nerve regeneration. The etiology of idiopathic blepharospasm, a disorder of the central nervous system, and hemifacial spasm, a condition involving the facial nerve of the peripheral nervous system, is markedly different. We discuss established methods of managing patients and highlight new approaches.

Photophobia in essential blepharospasm--a positron emission tomographic study

To localize regional alterations in cerebral glucose metabolism in essential blepharospasm (EB) patients with photophobia. We have studied 22 EB patients by performing positron emission tomography and [(18)F]-fluorodeoxyglucose analysis. The patients were classified into two subgroups, namely, EB with photophobia (P group) and EB without photophobia (NP group), and compared with a healthy control group (n = 44). There were no significant differences between the two patient groups with respect to the severity of motor symptoms or the duration for which the condition persisted. The FDG-PET images were analyzed using the statistical parametric mapping software. As compared to the control group, the P group exhibited significant hypermetabolism in the thalamus (P = 0.002), while the NP group exhibited significant hypometabolism in the dorsal midbrain, especially, in the superior colliculus (P = 0.005). The P group exhibited significant hypermetabolism in the thalamus and the dorsal midbrain as compared to the NP group (P < 0.001). These findings suggest that photophobia in EB patients may be associated with abnormal hyperactivity in the thalamus. Either hyperactivity of the thalamus or hypoactivity of the superior colliculus, or both may be associated with excessive blinking in these patients.

The effect of bangerter occlusion foils on blepharospasm and hemifacial spasm in occlusion-positive and occlusion-negative patients

Objective:

To test the hypothesis that occlusion-positive (OP) patients with blepharospasm (BEB) or hemifacial spasm (HFS) will benefit from a Bangerter occlusion foil (BOF), compared to occlusion-negative (ON) patients. OP/ON was based on immediate improvement in spasm with placement of a hand in front of either eye.

Design:

Prospective non-randomised single-centre pilot study.

Participants:

Fifteen-patients (6 BEB, 9 HFS).

Methods:

Patients were identified as OP or ON and wore highest-density BOF tolerable over one spectacle lens for 1 month. Outcomes were assessed at 1 month.

Main Outcome Measures:

Validated quality-of-life questionnaire (CDQ-24), scores of blink-rate and spasm severity assessed by two observers from video-recordings.

Results:

OP group had mean improvement in all scores. There was no change or worsening of scores in the ON group. In both BEB and HFS, more OP patients reported subjective benefit from wearing a foil (2 of 4 BEB, and 2 of 2 HFS) compared to the ON group (0 of 2 BEB, and 1 of 7 HFS).

Conclusion:

OP patients with BEB and HFS are more likely to experience improvement in spasms from wearing a BOF compared to ON patients. The occlusion test should be considered on all patients with BEB or HFS.

FL-41 tint improves blink frequency, light sensitivity, and functional limitations in patients with benign essential blepharospasm

OBJECTIVE

The objective of these 2 studies was to assess the efficacy of FL-41-tinted lenses in the treatment of benign essential blepharospasm (BEB).

DESIGN

A randomized crossover study and a randomized crossover case-control study.

PARTICIPANTS

The first study included 30 subjects with BEB. The second study included 26 subjects with BEB and 26 controls.

METHODS

For the first study, subjects were randomized to wear either FL-41 or gray-tinted lenses for 2 weeks. After a 2-week washout period, the other lens was worn for 2 weeks. Questionnaires were completed at baseline, after the first lens, and after the second lens. In the second study, surface electromyography (EMG) was used to measure blink frequency, duration, and force while subjects read and wore FL-41, rose, or gray-tinted lenses.

MAIN OUTCOME MEASURES

Questionnaires were used to assess perceptions of light sensitivity and the effect of light sensitivity on activities of daily living (ADL). EMG was used to measure blink frequency, duration, and force.

RESULTS

Most participants observed improvement while wearing both FL-41 and gray-tinted lenses. FL-41-tinted lenses provided superior improvement in the areas of reading, fluorescent light sensitivity, overall light sensitivity, blepharospasm frequency, and blepharospasm severity. FL-41 lenses reduced mean blink rate compared with both rose and gray-tinted lenses, and reduced eyelid contraction force compared with rose-tinted lenses.

CONCLUSIONS

FL-41 lenses provided both subjective and objective benefit to subjects with BEB. Physicians should consider recommending this noninvasive and inexpensive lens tint to patients with BEB.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Update on blepharospasm: report from the BEBRF International Workshop

This review updates understanding and research on blepharospasm, a subtype of focal dystonia. Topics covered include clinical aspects, pathology, pathophysiology, animal models, dry eye, photophobia, epidemiology, genetics, and treatment. Blepharospasm should be differentiated from apraxia of eyelid opening. New insights into pathology and pathophysiology are derived from different types of imaging, including magnetic resonance studies. Physiologic studies indicate increased plasticity and trigeminal sensitization. While botulinum neurotoxin injections are the mainstay of therapy, other therapies are on the horizon.

The evaluation of light sensitivity in benign essential blepharospasm

PURPOSE

To test light sensitivity thresholds rigorously in patients with benign essential blepharospasm (BEB) compared with patients who have known light sensitivity (migraineurs) and to normal control subjects.

DESIGN

Prospective, observational, case control study.

METHODS

We recruited a total of 87 subjects into each of three groups: BEB, migraine, and normal control subjects. A modified slit-lamp chin rest, heat shield, light meter, and halogen light that was modulated by a rheostat were used to measure light sensitivity thresholds. Participants were tested without spectacles, with gray-tinted spectacles, and with FL-41-tinted spectacles.

RESULTS

Light discomfort thresholds for subjects with BEB were significantly lower compared with normal control subjects (P < or = .009) and similar to the migraine group. Both gray and FL-41-tinted lenses improved light sensitivity thresholds in all groups (P < or = .0005). There was no observed difference in the improvement in light sensitivity when the gray and FL-41-tinted lenses were compared.

CONCLUSION

Patients with BEB are considerably more sensitive to light than control subjects and as sensitive to light as patients with migraine. Physicians who care for patients with BEB should consider using tinted lenses to help ameliorate symptoms.