Retinal changes in myotonic dystrophy: a clinicomorphological study

Ocular findings in a Spanish cohort of myotonic dystrophy type 1

PURPOSE

Myotonic dystrophy type 1 is the most common muscular dystrophy in adulthood, caused by a triplet repeat in chromosome 19q13.3. The present study investigates the frequency of the different ocular alterations in Spanish patients with DM1 and its relationship with the severity of the genetic alteration.

METHODS

Cross-sectional and multicenter study was conducted on patients with genetically confirmed DM1. Ophthalmologic examinations included visual acuity assessment, manifest refraction, slit-lamp biomicroscopy, tonometry, ocular motility, corneal tomography, and macular and optic nerve optical coherence tomography.

RESULTS

A total of 42 patients (84 eyes) were included. Mean age was 46.9 ± 13.4 (SD) years, and 57.1% were women. Fifteen patients had undergone cataract surgery in at least one eye (35.7%), and 13 (30.9%) had significant cataract. Mean intraocular pressure (IOP) was 10.5 ± 2.9 mmHg, and mean central corneal thickness (CCT) was 580.04 ± 48.61 μm. Half of the patients had significant ptosis, and 8 patients (9.75%) had undergone eyelid surgery. Macular abnormalities included retinal pigment epithelium alterations in 8 eyes of 6 patients, epiretinal membrane in 3 eyes, and lamellar hole in 2 eyes. A moderate correlation was found between IOP and ptosis with the number of triplet repeats.

CONCLUSION

Early cataract onset, low IOP, thicker CCT, and ptosis were the most significant manifestations of DM in our sample. Correlation found between IOP and ptosis with CTG repeat could be interesting in order to improve diagnosis and medical care of these patients but should be confirmed in further studies.

Clinical Characteristics, Differential Diagnosis and Genetic Analysis of Concentric Retinitis Pigmentosa

Concentric retinitis pigmentosa (RP), in which retinal degeneration is limited in the periphery, is rare and little information exists to date on the subject. Herein, we describe the clinical and genetic characteristics of this atypical form of RP. We retrospectively reviewed our database and identified 14 patients with concentric RP. Additionally, 14 patients with age-matched typical RP were also included. Patients with concentric RP had better visual acuity (logarithm of minimum angle of resolution −0.04 vs. 0.32, p = 0.047) and preserved ellipsoid zones (7630 µm vs. 2646 µm, p < 0.001) compared to typical RP. The electroretinogram showed subnormal but recordable responses in patients with concentric RP. Genetic testing was done in nine patients with concentric RP and revealed causative mutations in the EYS gene in one patient and the RP9 gene in one patient. Two patients had myotonic dystrophy and the diagnosis was revised as myotonic dystrophy-associated retinopathy. Concentric RP is a rare, atypical form of RP with better visual function. There is some overlap in the causative genes in concentric and typical RP. Myotonic dystrophy-associated retinopathy is an important differential diagnosis.

Ophthalmic manifestations of inherited neurodegenerative disorders

Ophthalmic findings are common features of neurodegenerative disorders and, in addition to being clinically important, have emerged as potentially useful biomarkers of disease progression in several conditions. Clinically, these visual system abnormalities can be a clue to diagnosis, as well as being a prominent cause of disability in affected patients. In this Review, we describe the various afferent visual system and other ophthalmic features of inherited neurodegenerative disorders, including the muscular dystrophies, Friedreich ataxia, the spinocerebellar ataxias, hereditary spastic paraplegia, Charcot-Marie-Tooth disease, and other conditions. We focus on the expanding role of optical coherence tomography in diagnostic imaging of the retina and optic nerve head, and the possible use of ophthalmic findings as biomarkers of disease severity in hereditary neurodegenerative disorders. In addition, we discuss the ophthalmic manifestations and treatment implications of mitochondrial dysfunction, which is a feature of many inherited neurodegenerative diseases.

Hypermetropia and esotropia in myotonic dystrophy

PURPOSE

To review detailed ophthalmic examinations of myotonic dystrophy patients especially with regard to refractive error and ocular alignment.

METHODS

Retrospective chart review of detailed ophthalmic examinations of 32 patients (27 children and 5 adults) with myotonic dystrophy.

RESULTS

The majority (86%) of eyes were hypermetropic. The average degree of hypermetropia was +6.0 D for children and +2.10 D for adults: 56% of children had esotropia; 22% had amblyopia.

CONCLUSIONS

Children with myotonic dystrophy should receive detailed eye examinations with emphasis placed on recognition and management of hypermetropia and strabismus.

Management of myogenic ptosis

OBJECTIVE

To review the genetics, clinical features, and management of patients affected by myogenic ptosis.

DESIGN

Retrospective, noncomparative interventional case series.

PARTICIPANTS

Twenty-eight patients with myogenic ptosis.

METHODS

A review of all patients with myogenic ptosis between 1992 and 2000 was made in a tertiary oculoplastics practice.

MAIN OUTCOME MEASURES

Ocular and systemic findings associated with myogenic ptosis were examined. Patients were diagnosed clinically, and ancillary tests (including genetic tests and muscle biopsy histologic findings) were reviewed. Surgical management principles and complications are discussed.

RESULTS

Most of our ptosis patients had chronic progressive external ophthalmoplegia (43%), oculopharyngeal muscular dystrophy (OPMD; 18%), and myotonic dystrophy (18%). Fifty percent of myogenic ptosis patients in our series underwent frontalis suspensions. Twenty-one percent of patients who initially had operations at our institution had minor complications, most related to corneal exposure. The most common ocular finding other than ptosis and ophthalmoplegia was pigmentary retinopathy (25%). The most common systemic finding in our patients was dysphagia (43%). Genetic testing for OPMD was highly sensitive. Muscle biopsy results for mitochondrial myopathies were less accurate as adjunctive diagnostic tests.

CONCLUSIONS

Myogenic ptosis should be considered in the differential diagnosis of any atypical ptosis presentation. To avoid complications, surgery should be performed only when the visual axis is obscured. We recommend the use of silicone slings in any patient with severe ptosis and less than 8 mm of levator function. Genetic testing of patients with myogenic ptosis is important to allow accurate diagnosis and to permit appropriate counseling on potentially life-threatening health issues.

Foveal photopigment kinetics--abnormality: an early sign in myotonic dystrophy?

Twelve subjects with minimal expression of the myotonic dystrophy (MyD) gene were investigated by retinal densitometry, a technique which has been used to study the properties of photopigments in the living eye and to detect photoreceptor abnormalities. Other investigations included slit-lamp examination, funduscopy, raleigh matches with the anomaloscope, tonometry, and neurological examination, including electroretinography (ERG) and pattern visual evoked potentials recording. Foveal densitometry demonstrated reduced values of the macular photopigment density difference with normal photopigment kinetics in early phases of the disease, even in asymptomatic individuals. The densitometric values correlated with decreased amplitudes of the photopic ERG a-wave. These findings may be explained by loss or dysfunction of the outer segments of foveal receptors. It is yet unknown whether or not these changes are secondary to other observed neuroretinal abnormalities in MyD. The most likely explanation might be an abnormality of the Na, Ca:K exchanger at the level of the outer segments of the photoreceptors whether or not in combination with a dysfunction of voltage generation systems, involving both photoreceptors and retinal pigment epithelium.