Strabismus surgery for diplopia in chronic progressive external ophthalmoplegia

Mitochondrial Chronic Progressive External Ophthalmoplegia

BACKGROUND

Chronic progressive external ophthalmoplegia (CPEO) is a rare disorder that can be at the forefront of several mitochondrial diseases. This review overviews mitochondrial CPEO encephalomyopathies to enhance accurate recognition and diagnosis for proper management.

METHODS

This study is conducted based on publications and guidelines obtained by selective review in PubMed. Randomized, double-blind, placebo-controlled trials, Cochrane reviews, and literature meta-analyses were particularly sought.

DISCUSSION

CPEO is a common presentation of mitochondrial encephalomyopathies, which can result from alterations in mitochondrial or nuclear DNA. Genetic sequencing is the gold standard for diagnosing mitochondrial encephalomyopathies, preceded by non-invasive tests such as fibroblast growth factor-21 and growth differentiation factor-15. More invasive options include a muscle biopsy, which can be carried out after uncertain diagnostic testing. No definitive treatment option is available for mitochondrial diseases, and management is mainly focused on lifestyle risk modification and supplementation to reduce mitochondrial load and symptomatic relief, such as ptosis repair in the case of CPEO. Nevertheless, various clinical trials and endeavors are still at large for achieving beneficial therapeutic outcomes for mitochondrial encephalomyopathies.

KEY MESSAGES

Understanding the varying presentations and genetic aspects of mitochondrial CPEO is crucial for accurate diagnosis and management.

A review of surgical management of progressive myogenic ptosis

PURPOSE

Surgical correction of myogenic ptosis is a sophisticated endeavor, as the disease is progressive and the post-operative course is prone to significant complications. We sought to review the literature for repair techniques in different types of myogenic ptosis.

METHODS

A PubMed/MEDLINE literature search of publications pertaining to surgical outcomes of progressive myogenic ptosis repair was performed. Studies included were original retrospective studies with a minimum of four patients.

RESULTS

A total of 27 articles were identified and divided by etiology of myogenic ptosis; either chronic progressive external ophthalmoplegia (CPEO), oculopharyngeal muscular dystrophy (OPMD), myasthenia gravis (MG), or mixed. Surgical techniques predominantly involved levator advancement, levator resection, frontalis sling, blepharoplasty, and Fasanella-Servat. Success rates ranged from 60.5% to 100%. Significant postoperative complications included ptosis recurrence, under-correction, over-correction, keratopathy, lagophthalmos, sling exposure, and sling infection.

CONCLUSION

Like surgical repair for other forms of ptosis, correction of progressive myogenic ptosis is guided by levator excursion. However, myogenic ptosis is especially challenging as it is characterized by worsening ptosis and the loss of protective corneal mechanisms. The goals of care with myogenic ptosis involves repairing ptosis just sufficiently to alleviate visual obstruction while avoiding adverse post-operative complications. This intentional under-correction subsequently increases susceptibility for ptosis recurrence. Myogenic ptosis repair therefore requires delicate balancing between function, sustained repair, and corneal protection.

Analysis of Improvement Time and Influencing Factors of Diplopia after Intermittent Exotropia in Children

Objective

To observe and analyze the occurrence rate, improvement time, and influencing factors of diplopia after intermittent exotropia in children.

Methods

A total of 135 children with intermittent exotropia treated in our hospital from February 2019 to April 2021 were recruited. A reasonable surgical plan was exerted according to the preoperative examination of the children, the children were divided into groups according to their age, degree of strabismus, visual acuity, and binocular visual function, and the postoperative diplopia occurrence rate and improvement time of diplopia in different groups were observed and compared.

Results

Postoperative diplopia occurred in 74 of 135 children with intermittent exotropia, and the postoperative incidence of diplopia was 54.81%. All diplopia occurred on the first day after the operation. There were 62 cases of contradictory diplopia (83.78%) and 12 cases of fusion of powerless diplopia (16.22%). Except for 1 case of amalgamated powerless diplopia, diplopia was not significantly improved after 6 months, which seriously affected the life of the children after the second operation, and all the others were significantly improved within 90 days. The improvement time of diplopia was 3-90 days, and the average improvement time of diplopia was 13.25 ± 3.16 days. According to their age, the children were divided into the 3-6 years old group (n = 69), the 7-10 years old group (n = 47), and the 11-14 years old group (n = 19). Postoperative diplopia occurred in 25 cases (36.23%) in the 3-6 years old group, 34 cases (72.34%) in the 7-10 years old group, and 16 cases (84.21%) in the 11-14 years old group. There was a significant difference in the incidence of postoperative diplopia among the three groups (P < 0.05). There was a significant difference in the improvement time of diplopia among the three groups (P < 0.05). According to the degree of strabismus before the operation, the children were divided into the <50△ group (n = 74) and the ≥50△ group (n = 61). Postoperative diplopia occurred in 32 cases (43.24%) in the <50△ group and 43 cases (70.49%) in the ≥50△ group. There was a significant difference in the incidence of postoperative diplopia between the two groups (P < 0.05). There was a significant difference in the improvement time of diplopia among the three groups (P < 0.05). According to the results of the visual acuity examination, the patients were divided into the ≥0.8 (naked eye) group (n = 21), the ≥0.8 (ametropia) group (n = 32), and the <0.8 (amblyopia) group (n = 32). Among them, diplopia occurred in 10 cases (47.62%) in the ≥0.8 (naked eye) group, 40 cases (48.78%) in the ≥0.8 (ametropia) group, and 24 cases (75.00%) in the <0.8 (amblyopia) group. The incidence of diplopia in the <0.8 (amblyopia) group was significantly higher than that in the ≥0.8 (naked eye) group and the ≥0.8 (ametropia) group, and the difference was statistically significant (P < 0.05). The postoperative diplopia improvement time in the <0.8 (amblyopia) group was significantly higher than that in the ≥0.8 (naked eye) group and the ≥0.8 (ametropia) group, and the difference was statistically significant (P < 0.05). There was no significant difference in diplopia occurrence rate and diplopia improvement time between the ≥0.8 (naked eye) group and the ≥0.8 (ametropia) group (P > 0.05). According to the results of binocular visual function examination, 92 cases had a primary function, 45 cases (48.91%) had diplopia after the operation, the average recovery time of diplopia was 12.58 ± 3.16, 43 cases had no primary function, and 30 cases (69.77%) had diplopia after the operation. The average recovery time of diplopia was 13.02 ± 3.84. There was a significant difference in the incidence of diplopia between the two groups (χ 2 = 5.162). There was no significant difference in the recovery time of diplopia between the two groups (χ 2 = 0.570, P < 0.05). In 80 cases with secondary function, diplopia occurred in 36 cases (45.00%), and the average recovery time of diplopia was 10.14 ± 2.88; in 55 cases without secondary function, diplopia occurred in 39 cases (70.91%), and the average recovery time of diplopia was 14.86 ± 3.73. There was a significant difference in the incidence of diplopia between the two groups (χ 2 = 8.861, P < 0.002). There was a significant difference in the recovery time of diplopia between the two groups (χ 2 = 6.469, P < 0.001). In 77 cases with tertiary function, diplopia occurred in 32 cases (41.56%), and the average recovery time of diplopia was 9.61 ± 2.39; in 58 cases without tertiary function, diplopia occurred in 43 cases (74.14%), and the average recovery time of diplopia was 13.11 ± 3.05. There was a significant difference in the incidence of diplopia between the two groups (χ 2 = 14.221 P < 0.001). There was a significant difference in the recovery time of diplopia between the two groups (χ 2 = 5.355, P < 0.001).

Conclusions

The age, degree of strabismus, visual acuity, and binocular visual function of children with intermittent exotropia are significant factors affecting the occurrence rate and recovery time of diplopia after the operation. The younger the age, the smaller the degree of strabismus, the better the vision and the second or third grade of visual function, the smaller the occurrence rate of diplopia, and the shorter the recovery time of diplopia. Thus, the above influencing factors have a certain guiding significance in predicting the improvement of postoperative diplopia and the time of diplopia disappearance. The purpose of intermittent exotropia surgery in children is not only to correct eye position and improve appearance but also to establish normal retinal correspondence in order to obtain binocular monocular function. Furthermore, postoperative diplopia in children with concomitant exotropia is very common; therefore, careful examination, comprehensive analysis, and surgical plan should be designed according to the above factors. Stereoscopic vision training as early as possible after the operation is beneficial to the establishment of normal retinal correspondence and the elimination of diplopia.

Strabismus in chronic progressive external ophthalmoplegia

PURPOSE

To elucidate the patterns of strabismus and ophthalmoplegia associated with chronic progressive external ophthalmoplegia (CPEO) confirmed by mitochondrial DNA (mtDNA) deletions in Asians.

METHODS

A total of 10 patients confirmed to have mtDNA deletion associated with CPEO were included. Long-range PCR encompassing the entire mtDNA was carried out. In the cases with mtDNA deletion, the exact deletion ranges of mtDNA were identified by sequencing. A full ophthalmologic examination including prism and alternate cover test in the primary position, evaluation of ductions and versions, and binocularity was performed in 10 patients with confirmed mtDNA deletions associated with CPEO.

RESULTS

All of the patients showed ophthalmoplegia as well as ptosis, even after eyelid surgeries. Ophthalmoplegia was symmetric between both eyes in nine patients (90%) while one patient (10%) showed asymmetric ophthalmoplegia with esotropia and left hypotropia. Among the nine patients with symmetric involvement, four patients (44%) showed exotropia, three (33%) had exotropia with vertical deviation, and the remaining two patients (22%) showed orthotropia. Five out of 10 patients (50%) complained of diplopia associated with strabismus, four of whom (80%) had vertical deviation. Three out of five patients (60%) without diplopia showed exotropia of 20 prism diopters (PD) to 50 PD.

CONCLUSIONS

Exotropia with/without vertical deviation is the most common form of strabismus in Asian patients with CPEO and only one of them showed a small angle of esotropia. Ophthalmoplegia could be asymmetric in 10% of CPEO patients.

Neuro-ophthalmic manifestations of mitochondrial disorders and their management

The visual system has high metabolic requirements and is therefore particularly vulnerable to mitochondrial dysfunction. The most commonly affected tissues include the extraocular muscles, photoreceptors, retinal pigment epithelium, optic nerve and visual cortex. Hence, the most common manifestations of mitochondrial disorders are progressive external ophthalmoplegia, macular pattern dystrophy, pigmentary retinopathy, optic neuropathy and retrochiasmal visual field loss. With the exception of Leber hereditary optic neuropathy and stroke-like episodes seen in mitochondrial encephalopathy, lactic acidosis and stroke-like episodes, the majority of neuro-ophthalmic manifestations have an insidious onset. As such, some patients may not recognize subtle progressive visual symptoms. When mitochondrial disorders are highly suspected, meticulous examination performed by an ophthalmologist with targeted ancillary testing can help confirm the diagnosis. Similarly, neuro-ophthalmic symptoms and signs may be the first indication of mitochondrial disease and should prompt systemic investigations for potentially life-threatening associations, such as cardiac conduction defects. Finally, the ophthalmologist can offer symptomatic treatments for some of the most disabling manifestations of these disorders.

Non-traumatic and non-drug-induced rhabdomyolysis

Rhabdomyolysis (RM), a fortunately rare disease of the striated muscle cells, is a complication of non-traumatic (congenital (glycogen storage disease, discrete mitochondrial myopathies and various muscular dystrophies) or acquired (alcoholic myopathy, systemic diseases, arterial occlusion, viral illness or bacterial sepsis)) and traumatic conditions. Additionally, RM can occur in some individuals under specific circumstances such as toxic substance use and illicit drug abuse. Lipid-lowering drugs in particular are capable of causing RM. This comprehensive review will focus on non-traumatic and non-drug-induced RM. Moreover, the pathology of RM, its clinical manifestation and biochemical effects, and finally its management will be discussed.