Shedding Light on Blepharospasm: A Patient–Researcher Partnership Approach to Assessment of Photophobia and Impact on Activities of Daily Living

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.

Treatment of strabismus and blepharospasm with Botox (onabotulinumtoxinA): Development, insights, and impact

Strabismus, deviation of the ocular alignment, can adversely affect quality of life and activities of daily living. Surgery was the prior standard of care for strabismus, but up to 40% of patients required additional surgeries. This need for more effective and less invasive treatment, along with the convergence of other events such as the development of electromyography, purification of botulinum toxin A, and the finding that injection of botulinum toxin type A could paralyze the hind limbs of chicks, led Dr. Alan Scott to investigate injection of his formulation for strabismus. The positive results of initial trials in monkeys segued to human trials with observations of alignment improvements and few adverse events. The success of botulinum toxin type A in the treatment of strabismus led to interest in its use to treat other skeletal muscles, particularly in blepharospasm, a type of focal dystonia involving eyelid spasms and involuntary eye closure that lacked an effective pharmacological treatment. Patient groups helped to increase awareness of this novel treatment, and results from clinical trials confirmed its effectiveness. Dr. Scott's formulation, then known as Oculinum, received its first Food and Drug Administration approvals in 1989 for strabismus and blepharospasm. Allergan acquired Oculinum in 1991, renaming it Botox. These initial uses led to its application in a myriad of other indications as outlined in other articles of this supplement.

The Unmet Challenge of Diagnosing and Treating Photophobia

BACKGROUND

Although patients with abnormal light sensitivity may present to an ophthalmologist or optometrist for the evaluation of photophobia, there are no previous reviews of the most common causes of this symptom.

METHODS

We conducted a retrospective chart review of patients who presented to our eye center between 2001 and 2009 primarily for the evaluation of photophobia. We recorded demographics, ocular examination findings, and diagnoses of these patients.

RESULTS

Our population included 58 women and 53 men. The mean age at presentation to the clinic was 37 years (range 6 months-94 years). The most frequent cause of photophobia was migraine headache (53.7%), followed by dry eye syndrome (36.1), ocular trauma (8.2%), progressive supranuclear palsy (6.8%), and traumatic brain injury (4.1%). A significant proportion of patients (25.9%) left the clinic without a cause for their photophobia documented by the examining physician (11.7% of adults and 69.4% of children).

CONCLUSIONS

Photophobia affects patients of all ages, and many patients are left without a specific diagnosis, indicating a significant knowledge gap among ophthalmologists and optometrists evaluating these patients.

Increased pupillary constriction velocity in benign essential blepharospasm associated with photophobia

We evaluated whether the pupillary light reflex is altered in benign essential blepharospasm patients. Twenty-three patients with benign essential blepharospasm, 47 with reflex blepharospasm, and 29 dry eye disease controls were included. Pupillary light reflex-related parameters were measured under mesopic (10 lux) and photopic illuminance (200 lux) using an infrared pupillometer. Additionally, we assessed photophobia grade, eyelid function, and dry eye disease-related parameters. There were no differences in age, sex predominance, or dry eye disease-related parameters among the three groups, or in photophobia grade and eyelid function between benign essential blepharospasm and reflex groups. Constriction velocity and maximum constriction velocity in the mesopic condition were significantly greater in the benign essential blepharospasm group (3.26 ± 0.56 and 5.27 ± 0.90 mm/s) than in reflex (2.86 ± 0.62 and 4.59 ± 1.00 mm/s) or dry eye disease groups (2.96 ± 0.46 and 4.72 ± 0.67 mm/s). Constriction velocity and maximum constriction velocity in the mesopic condition positively correlated with photophobia grade (r = 0.525 and 0.617, P = 0.025 and 0.006) in the benign essential blepharospasm group. Pupillary light reflex may be related to the pathophysiology of benign essential blepharospasm with photophobia. Further studies are required to reveal connections among pupillary light reflex, photophobia, and focal dystonia in benign essential blepharospasm patients with photophobia.

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.

Structural and Functional Assessment in Patients Treated with Systemic Isotretinoin Using Optical Coherence Tomography and Frequency-Doubling Technology Perimetry

A causal association between central nervous system neuropathy and oral isotretinoin has been reported. In this study we aimed to assess retinal nerve fibre layer (RNFL) thickness and visual field changes in patients treated with systemic isotretinoin. Thirty-nine patients treated with 1 mg/kg daily oral isotretinoin were enrolled in this prospective clinical trial. All patients underwent complete ophthalmologic assessment before treatment, on day 60, and 3 months after completion of treatment. RNFL thickness measurements were performed with Stratus optical coherence tomography. Functional testing included frequency-doubling technology perimetry and Humphrey field analyser. Main outcome measures were average RNFL thicknesses and visual field indices (mean deviation, pattern standard deviation). Measurements of RNFL thickness showed no statistically significant change between the three measurements (p = 0.180). No statistically significant differences were observed in the frequency-doubling technology indices (mean deviation and pattern standard deviation, p = 0.066 and p = 0.103, respectively) and in the Humphrey field analyser indices (mean deviation and pattern standard deviation, p = 0.091 and p = 0.087, respectively) at day 60 of treatment or 3 months after the cessation of treatment. In this study of 39 patients, systemic use of isotretinoin (1 mg/kg daily) does not cause a statistically significant change in peripapillary RNFL thickness or visual field findings within the usage period, and within 3 months after cessation.

Shedding light on photophobia

Photophobia is a common yet debilitating symptom seen in many ophthalmic and neurologic disorders. Despite its prevalence, it is poorly understood and difficult to treat. However, the past few years have seen significant advances in our understanding of this symptom. We review the clinical characteristics and disorders associated with photophobia, discuss the anatomy and physiology of this phenomenon, and conclude with a practical approach to diagnosis and treatment.

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.