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Edge-light pupil cycle time and optic nerve disease.
Annals of Ophthalmology
|August 1, 1983
Summary
Edge-light pupil cycle time (EPCT) quantifies pupil light reaction, assessing optic nerve health. Abnormal EPCT values were found in 100% of optic atrophy cases and 83% of multiple sclerosis patients.
Area of Science:
- Ophthalmology
- Neuroscience
- Physiology
Background:
- The pupillary reflex arc is crucial for vision.
- Edge-light pupil cycle time (EPCT) measures the afferent pathway of this reflex.
- EPCT serves as an objective indicator of optic nerve function.
Purpose of the Study:
- To establish normative values for edge-light pupil cycle time.
- To assess the utility of EPCT in diagnosing optic nerve diseases.
- To evaluate EPCT's sensitivity in conditions like optic atrophy and multiple sclerosis.
Main Methods:
- Determined pupil cycle times in 30 healthy subjects (60 eyes).
- Established mean and upper limits of normal for EPCT and inter-eye difference.
- Measured EPCT in patients with optic atrophy, multiple sclerosis, and undiagnosed neurological conditions.
Main Results:
- Established normal EPCT mean of 814 ms (upper limit 935 ms) and inter-eye difference (upper limit 79 ms).
- 100% of eyes with optic atrophy showed abnormal EPCT.
- 83% of eyes in multiple sclerosis patients exhibited abnormal EPCT.
Conclusions:
- Edge-light pupil cycle time provides a reliable, quantitative measure of optic nerve function.
- Abnormal EPCT is highly indicative of optic nerve dysfunction, particularly in optic atrophy and multiple sclerosis.
- EPCT is a valuable diagnostic tool for neuroophthalmic diseases affecting the optic nerve.