Assessment of visual function in chronic progressive external ophthalmoplegia

Application of Femtosecond Laser + Piggyback Multifocal Intraocular Lens Implantation in Patients with Super-High Myopia Complicated with Cataract

OBJECTIVE

To observe the clinical effect of piggyback multifocal intraocular lens (IOL) implantation in treating patients with high myopia complicated with cataract.

METHODS

This was a prospective controlled study. We compared 32 eyes of 32 patients who underwent femtosecond laser-assisted cataract surgery with piggyback IOL implantation (two IOLs were implanted into the capsule) with 32 eyes of 32 patients who also underwent the same surgery (one IOL implanted into the capsule) due to high myopia complicated with cataract at the Wuhan Aier Eye Expert Hospital between January 2019 and October 2020. All patients were followed up for three months after surgery. Uncorrected distance visual acuity (UCDVA), uncorrected intermediate visual acuity (UCIVA), uncorrected near visual acuity (UCNVA), best-corrected distance visual acuity, distance-corrected intermediate visual acuity (DCIVA), distance-corrected near visual acuity (DCNVA), postoperative spectacle independence, postoperative visual interference, equivalent spherical lens, defocus curve, and IOL tilt and eccentricity were evaluated.

RESULTS

Three months after surgery, the patients' UCIVA, UCNVA, DCIVA, and DCNVA were 0.49 ± 0.07, 0.38 ± 0.15, 0.47 ± 0.09, and 0.36 ± 0.12, respectively, in the research group and 0.56 ± 0.18, 0.72 ± 0.22, 0.55 ± 0.13, and 0.69 ± 0.15, respectively, in the control group; the differences between the two groups were statistically significant (P < .05). The spectacle independence rate was higher in the research group (93%) than in the control group (13%). The overall satisfaction regarding postoperative visual quality was also higher in the research group than in the control group. The absolute mean value of the spherical equivalents was 0.48 ± 0.28 D in the research group and 0.62 ± 0.33 D in the control group; the difference between the two groups was statistically significant (P < .05).

CONCLUSION

Piggyback multifocal IOL implantation can expand the multifocal IOL application range, and satisfy the desire of patients with high myopia complicated with cataract to see both near and far.

CONVENTIONAL APPROACHES TO THE THERAPY OF HEREDITARY MYOPATHIES

The aim of the work was to analyze the available therapeutic options for the conventional therapy of hereditary myopathies.

Materials and methods. When searching for the material for writing a review article, such abstract databases as PubMed and Google Scholar were used. The search was carried out on the publications during the period from 1980 to September 2022. The following words and their combinations were selected as parameters for the literature selection: “myopathy”, “Duchenne”, “myodystrophy”, “metabolic”, “mitochondrial”, “congenital”, “symptoms”, “replacement”, “recombinant”, “corticosteroids”, “vitamins”, “tirasemtiv”, “therapy”, “treatment”, “evidence”, “clinical trials”, “patients”, “dichloracetate”.

Results. Congenital myopathies are a heterogeneous group of pathologies that are caused by atrophy and degeneration of muscle fibers due to mutations in genes. Based on a number of clinical and pathogenetic features, hereditary myopathies are divided into: 1) congenital myopathies; 2) muscular dystrophy; 3) mitochondrial and 4) metabolic myopathies. At the same time, treatment approaches vary significantly depending on the type of myopathy and can be based on 1) substitution of the mutant protein; 2) an increase in its expression; 3) stimulation of the internal compensatory pathways expression; 4) restoration of the compounds balance associated with the mutant protein function (for enzymes); 5) impact on the mitochondrial function (with metabolic and mitochondrial myopathies); 6) reduction of inflammation and fibrosis (with muscular dystrophies); as well as 7) an increase in muscle mass and strength. The current review presents current data on each of the listed approaches, as well as specific pharmacological agents with a description of their action mechanisms.

Conclusion. Currently, the following pharmacological groups are used or undergoing clinical trials for the treatment of various myopathies types: inotropic, anti-inflammatory and antifibrotic drugs, antimyostatin therapy and the drugs that promote translation through stop codons (applicable for nonsense mutations). In addition, metabolic drugs, metabolic enzyme cofactors, mitochondrial biogenesis stimulators, and antioxidants can be used to treat myopathies. Finally, the recombinant drugs alglucosidase and avalglucosidase have been clinically approved for the replacement therapy of metabolic myopathies (Pompe’s disease).

Effect of an oculomotor rehabilitation program for subacute brain injury patients with ophthalmoplegia: a case-control study

PURPOSE

Examining the effects of an oculomotor rehabilitation program in subacute brain injury patients presenting with external ophthalmoplegia.

METHODS

This case-control study included 33 patients with subacute brain injury accompanied by external ophthalmoplegia (15 cases, 18 controls) from a hospital rehabilitation ward. Participants underwent comprehensive rehabilitation for 8 weeks. The patients participated in an oculomotor rehabilitation program, which involved inducing pursuit, fixation, saccade, and vergence for 20 min daily, 6 days a week for 8 weeks. We assessed improvements in the angle of strabismus; visual function index (VFI), which evaluates inconvenience in daily life; and diplopia after 8 weeks in the two groups using statistical methods.

RESULTS

The program resulted in an immediate strabismus angle improvement (p < 0.001). Strabismus angle change over the 8-week period was significantly higher (p < 0.001) in patients (22.9 ± 12.3°) than in control participants (8.3 ± 7.6°). VFI change was significantly greater (p = 0.003) in patients (7.1 ± 5.1 points) than in control participants (2.7 ± 2.4 points). The patients exhibited significantly higher diplopia improvement rates while looking straight ahead and in the direction of paralysis than did control participants (p = 0.021 and p = 0.037, respectively).

CONCLUSION

This program improved external ophthalmoplegia without any specialized environmental configurations or personnel, which ensures wide clinical applications.IMPLICATIONS FOR REHABILITATIONOur oculomotor rehabilitation program improved external ophthalmoplegia in subacute brain injury patients.The program promotes pursuit, fixation, saccades, and vergence. The patients lay in the supine position and it places a little burden on them.The program can be completed within 20 min daily, requires no special environmental configurations, and can be performed by anyone.

Rehabilitation practice for external ophthalmoplegia including voluntary training for patients with medial longitudinal fasciculus syndrome

Watabe T, Suzuki H, Abe M, Uchibori K, Senga K. Rehabilitation practice for external ophthalmoplegia including voluntary training for patients with medial longitudinal fasciculus syndrome. Jpn J Compr Rehabil Sci 2022; 13: 36-40.

Introduction

This report presents a case of external ophthalmoplegia caused by medial longitudinal fasciculus (MLF) syndrome. The patient underwent oculomotor rehabilitation by an occupational therapist during hospitalization and voluntary training supervised by the occupational therapist after discharge.

Case

The patient presented with MLF syndrome due to bridge infarction. The left eye had a pronounced adduction disorder, and diplopia was observed in the median vision, resulting in severe discomfort in daily life. During the hospitalization, the patient underwent eye movement rehabilitation led by an occupational therapist that included pursuit, fixation, saccades, and convergence, and after discharge from the hospital, the patient underwent two sets of voluntary training for 10 min daily to induce pursuit, fixation, and convergence under the guidance of the occupational therapist. As a result, the angle of squint, degree of diplopia, and degree of inconvenience in daily life improved.

Discussion

Eye movement rehabilitation, including voluntary training, improved external ophthalmoplegia.

Mitochondrial Disorders

BACKGROUND

Mitochondrial disorders are among the most common heritable diseases, with an overall lifetime risk of approximately one in 1500. Nonetheless, their diagnosis is often missed because of their extreme phenotypic and genotypic heterogeneity.

METHODS

This review is based on publications retrieved by a selective literature search on the clinical features, genetics, pathogenesis, diagnosis, and treatment of mitochondrial diseases.

RESULTS

Pathogenic defects of energy metabolism have been described to date in over 400 genes. Only a small number of these genes lie in the mitochondrial DNA; the corresponding diseases are either maternally inherited or of sporadic distribution. The remaining diseaseassociated genes are coded in nuclear DNA and cause diseases that are inherited according to Mendelian rules, mostly autosomal recessive. The most severely involved organs are generally those with the highest energy requirements, including the brain, the sensory epithelia, and the extraocular, cardiac, and skeletal musculature. Typical manifestations include epileptic seizures, stroke-like episodes, hearing loss, retinopathy, external ophthalmoparesis, exercise intolerance, and diabetes mellitus. More than two manifestations of these types should arouse suspicion of a disease of energy metabolism. The severity of mitochondrial disorders ranges from very severe disease, already evident in childhood, to relatively mild disease arising in late adulthood. The diagnosis is usually confirmed with molecular-genetic methods. Symptomatic treatment can improve patients' quality of life. The only disease-modifying treatment that has been approved to date is idebenone for the treatment of Leber hereditary optic neuropathy. Intravitreal gene therapy has also been developed for the treatment of this disease; its approval by the European Medicines Agency is pending.

CONCLUSION

Patients with mitochondrial diseases have highly varied manifestations and can thus present to physicians in practically any branch of medicine. A correct diagnosis is the prerequisite for genetic counseling and for the initiation of personalized treatment.

Clinical features of mtDNA-related syndromes in adulthood

Mitochondrial diseases are the most common inheritable metabolic diseases, due to defects in oxidative phosphorylation. They are caused by mutations of nuclear or mitochondrial DNA in genes involved in mitochondrial function. The peculiarity of "mitochondrial DNA genetics rules" in part explains the marked phenotypic variability, the complexity of genotype-phenotype correlations and the challenge of genetic counseling. The new massive genetic sequencing technologies have changed the diagnostic approach, enhancing mitochondrial DNA-related syndromes diagnosis and often avoiding the need of a tissue biopsy. Here we present the most common phenotypes associated with a mitochondrial DNA mutation with the recent advances in diagnosis and in therapeutic perspectives.

Extraocular muscle atrophy and central nervous system involvement in chronic progressive external ophthalmoplegia

Background

Chronic progressive external ophthalmoplegia (CPEO) is a classical mitochondrial ocular disorder characterised by bilateral progressive ptosis and ophthalmoplegia. These ocular features can develop either in isolation or in association with other prominent neurological deficits (CPEO+). Molecularly, CPEO can be classified into two distinct genetic subgroups depending on whether patients harbour single, large-scale mitochondrial DNA (mtDNA) deletions or multiple mtDNA deletions secondary to a nuclear mutation disrupting mtDNA replication or repair. The aim of this magnetic resonance imaging (MRI) study was to investigate whether the ophthalmoplegia in CPEO is primarily myopathic in origin or whether there is evidence of contributory supranuclear pathway dysfunction.

Methods

Ten age-matched normal controls and twenty patients with CPEO were recruited nine patients with single, large-scale mtDNA deletions and eleven patients with multiple mtDNA deletions secondary to mutations in POLG, PEO1, OPA1, and RRM2B. All subjects underwent a standardised brain and orbital MRI protocol, together with proton magnetic resonance spectroscopy in two voxels located within the parietal white matter and the brainstem.

Results

There was evidence of significant extraocular muscle atrophy in patients with single or multiple mtDNA deletions compared with controls. There was no significant difference in metabolite concentrations between the patient and control groups in both the parietal white matter and brainstem voxels. Volumetric brain measurements revealed marked cortical and cerebellar atrophy among patients with CPEO+ phenotypes.

Conclusion

The results of this study support a primary myopathic aetiology for the progressive limitation of eye movements that develops in CPEO.

Progressive external ophthalmoplegia (PEO) due to a mutation in the C10orf2 (PEO1) gene mimicking a myasthenic crisis

We described a case of a patient with autosomal dominant progressive external ophthalmoplegia (PEO) who presented with the acute onset dysphagia, quadriparesis, ptosis and respiratory insufficiency following a cardiac procedure and mimicking a myasthenic crisis. A pathogenic mutation in the C10orf2 (PEO1) gene was confirmed. The unusual presentation of our patient contributes to expand the clinical phenotype of PEO1 mutations and reinforces the need to consider mitochondrial myopathy as differential diagnosis of myasthenia gravis even in the case of acute onset symptoms.

Diagnosis and treatment of mitochondrial myopathies

Mitochondrial disorders are a heterogeneous group of disorders resulting from primary dysfunction of the respiratory chain. Muscle tissue is highly metabolically active, and therefore myopathy is a common element of the clinical presentation of these disorders, although this may be overshadowed by central neurological features. This review is aimed at a general medical and neurologist readership and provides a clinical approach to the recognition, investigation, and treatment of mitochondrial myopathies. Emphasis is placed on practical management considerations while including some recent updates in the field.

Mitochondrial DNA defects and selective extraocular muscle involvement in CPEO

PURPOSE. Chronic progressive external ophthalmoplegia (CPEO) is a prominent, and often the only, presentation among patients with mitochondrial diseases. The mechanisms underlying the preferential involvement of extraocular muscles (EOMs) in CPEO were explored in a comprehensive histologic and molecular genetic study, to define the extent of mitochondrial dysfunction in EOMs compared with that in skeletal muscle from the same patient. METHODS. A well-characterized cohort of 13 CPEO patients harboring a variety of primary and secondary mitochondrial (mt)DNA defects was studied. Mitochondrial enzyme function was determined in EOM and quadriceps muscle sections with cytochrome c oxidase (COX)/succinate dehydrogenase (SDH) histochemistry, and the mutation load in single muscle fibers was quantified by real-time PCR and PCR-RFLP assays. RESULTS. CPEO patients with mtDNA deletions had more COX-deficient fibers in EOM (41.6%) than in skeletal muscle (13.7%, P > 0.0001), and single-fiber analysis revealed a lower mutational threshold for COX deficiency in EOM. Patients with mtDNA point mutations had a less severe ocular phenotype, and there was no significant difference in the absolute level of COX deficiency or mutational threshold between these two muscle groups. CONCLUSIONS. The more pronounced mitochondrial biochemical defect and lower mutational threshold in EOM compared with skeletal muscle fibers provide an explanation of the selective muscle involvement in CPEO. The data also suggest that tissue-specific mechanisms are involved in the clonal expansion and expression of secondary mtDNA deletions in CPEO patients with nuclear genetic defects.

Dynamic properties of eye movements in mitochondrial chronic progressive external ophthalmoplegia

AIMS

To relate dynamic properties of eye movements to visual disability in a patient with chronic progressive external ophthalmoplegia (CPEO) due to mitochondrial DNA deletion.

METHODS

Visual function was evaluated by neuro-ophthalmological examination and visual function index (VF-14). Eye movements were measured using the magnetic search coil technique.

RESULTS

The patient denied diplopia or oscillopsia at rest or during locomotion. His range of eye movements was limited to <12 degrees horizontally, and <19 degrees vertically with smaller movements of the left eye. All classes of movements were impaired, but the eyes accelerated to over 1000 degrees /s/s at the onset of saccades and in response to brisk head rotations.

CONCLUSIONS

Diplopia and oscillopsia were suppressed, probably due to visual system adaptation during the slow disease progression. We postulate that relative sparing of pale global extraocular fibres accounted for preserved acceleration of saccades and vestibular eye movements.

How can we treat mitochondrial encephalomyopathies? Approaches to therapy

Mitochondrial disorders are a heterogeneous group of diseases affecting different organs (brain, muscle, liver, and heart), and the severity of the disease is highly variable. The chronicity and heterogeneity, both clinically and genetically, means that many patients require surveillance follow-up over their lifetime, often involving multiple disciplines. Although our understanding of the genetic defects and their pathological impact underlying mitochondrial diseases has increased over the past decade, this has not been paralleled with regards to treatment. Currently, no definitive pharmacological treatment exists for patients with mitochondrial dysfunction, except for patients with primary deficiency of coenzyme Q10. Pharmacological and nonpharmacological treatments increasingly being investigated include ketogenic diet, exercise, and gene therapy. Management is aimed primarily at minimizing disability, preventing complications, and providing prognostic information and genetic counseling based on current best practice. Here, we evaluate therapies used previously and review current and future treatment modalities for both adults and children with mitochondrial disease.