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Effect of darkness on upper eyelid position.
Lígia Cristina Viana Neves1, Antonio Augusto V Cruz
1Department of Ophthalmology, Otorhinolaryngology, and Head and Neck Surgery, School of Medicine of Ribeirão Preto-SP, São Paulo, Brazil.
Ophthalmic Plastic and Reconstructive Surgery
|March 22, 2005
Summary
Sudden darkness causes upper eyelid retraction in both healthy individuals and those with Graves disease. This reflex lessens with age and is not due to sympathetic nerve stimulation.
Area of Science:
- Ophthalmology
- Neuroscience
Background:
- Graves disease can cause upper eyelid retraction.
- The Muller muscle's role in eyelid movement is not fully understood.
Purpose of the Study:
- To quantify upper eyelid retraction induced by darkness.
- To compare this reflex in normal subjects and Graves patients.
- To assess the effect of guanethidine drops on this retraction.
Main Methods:
- Measured palpebral fissure images in photopic and dark conditions.
- Included 211 control subjects and 45 Graves patients.
- Assessed 21 Graves patients treated with guanethidine drops.
Main Results:
- Darkness induced upper eyelid retraction in all participants.
- Eyelid elevation was more pronounced in children.
- No significant difference in retraction magnitude between Graves patients and normal adults.
- Guanethidine drops did not eliminate the eyelid reflex.
Conclusions:
- Darkness provokes upper eyelid retraction in healthy individuals and Graves patients.
- The effect diminishes with age.
- The reflex is independent of sympathetic stimulation of the Muller muscle.