Ocular autonomic nerve function in Lambert-Eaton myasthenic syndrome

Area of Science:

• Ophthalmology
• Neurology
• Autonomic Nervous System Research

Background:

• Lambert-Eaton Myasthenic Syndrome (LEMS) is an autoimmune disorder affecting neuromuscular transmission.
• Autonomic dysfunction is increasingly recognized as a potential comorbidity in LEMS.
• Ocular autonomic innervation plays a crucial role in visual function and comfort.

Purpose of the Study:

• To investigate the prevalence and characteristics of autonomic dysfunction in the eye and ocular adnexae of LEMS patients.
• To compare ocular autonomic function in LEMS patients with age-matched healthy controls.
• To elucidate the association between LEMS and specific patterns of autonomic denervation.

Main Methods:

• Assessment of autonomic innervation in seven LEMS patients and 50 age-matched controls.
• Evaluation of pupil responses to light to assess autonomic pupillary function.
• Measurement of reflex tear production as a test of parasympathetic innervation.
• Testing for parasympathetic and sympathetic denervation hypersensitivity of the iris.

Main Results:

• Abnormal pupil responses to light were observed in 69% of LEMS patients versus 18% in controls.
• Reduced reflex tear production was noted in 69% of LEMS patients.
• Parasympathetic and sympathetic denervation hypersensitivity of the iris was present in 57% of LEMS patients, significantly higher than the 6% in controls.

Conclusions:

• Autonomic dysfunction, particularly affecting ocular structures, is common in Lambert-Eaton Myasthenic Syndrome.
• LEMS patients exhibit significant abnormalities in pupillary light responses, tear production, and iris autonomic innervation.
• These findings underscore the importance of evaluating autonomic function in the comprehensive management of LEMS.