A Child with Myasthenia Gravis and Defective Accommodation: A Case Study
Karen Pedemont, DipAppSc(Orth) DOBA 1,2
Neryla Jolly, DOBA(T) MA 2
Loreto Rose, BSc(Hons) MBBS(Hons) FRANZCO 3
1 Department of Orthoptics, Bankstown-Lidcombe Hospital, Sydney South West Area Health Service, Sydney, Australia
2 The University of Sydney, Faculty of Health Sciences, Sydney, Australia
3 Department of Ophthalmology, Bankstown-Lidcombe Hospital, Sydney South West Area Health Service, Sydney, Australia
Background: This case details a 14-year old female with myasthenia gravis (MG) who on presentation had ocular symptoms, which included bilateral ptosis and vertical diplopia. Four weeks after the onset of the MG she developed accommodative insufficiency. This condition has not been reported before in childhood MG, but has been documented in adult onset MG. The onset in this case was later in the course of the disease, not initially, as found in the adult cases reviewed in the literature.
Method: Measurements were taken at different stages over an 18-month period to determine the impact of medication and fatigue. Tests for near vision, accommodation, convergence, bar reading and near deviation were performed.
Results: All measurements were reduced and further affected by fatigue with the exception of the size of the near deviation. The patient was symptom-free by 15 weeks post onset. Eighteen months later the patient remained symptom-free with all measurements normal with the exception of accommodation, which remained below normal and affected by fatigue after reading.
Conclusion: This single case highlights the occurrence of smooth muscle involvement in MG and its debilitating effect. It is recommended that testing of accommodation function becomes standard practice in patients with MG and the use of additional plus lenses considered if required.
