Hydroxyamphetamine and dilute adrenaline are both used to localise 3rd order disease. Preganglionic Horner syndrome does not dilate as much.Ĭocaine and Apraclonidine are used to diagnose Horner syndrome. If there is a 3rd order lesion, significant dilation is seen. In Horner syndrome there is denervation hypersensitivity in these receptors, especially in 3rd order disease.
Used to distinguish 3rd order lesions from the others (postganglionic or preganglionic).Remember that medications are applied bilaterally, to both eyes.The principle underlying this test is denervation hypersensitivity.When Apraclonidine is administered, the Horner eye dilates even more than the normal eye. In Horner syndrome, the sympathetic pathway is broken and the effector muscles at the end of the pathway are hypersensitive.Apraclonidine is an alpha agonist that causes mydriasis in normal people.In Horner syndrome, the sympathetic pathway is broken so the Horner pupil will not dilate to Cocaine, but the normal one will.It blocks noradrenaline reuptake → enhances sympathetic effect and causes mydriasis in normal people.Used to confirm Horner syndrome, a lesion somewhere along the sympathetic chain.This pathway is outlined in detail on the principles of neuro-ophthalmology pageĪdministration of various topical medications bilaterally helps localise which order neuron is likely to be affected, and then relevant imaging of the high yield sites are conducted for diagnostics. It is caused by a lesion in the sympathetic pathway to the head and neck. Horner syndrome is a triad of: ptosis, anhidrosis and miosis. Holmes-adie syndrome is: Aldie pupil + decreased lower limb reflexes Treatment is with low dose pilocarpine to both eyes, causes denervation hypersensitivity constriction of the Aldie pupil and has no effect on normal pupilĪrgyll-Robertson Pupil By Chainwit, CC BY-SA 4.0. The light reflex is still lost.Ġ.1% pilocarpine (very dilute) → Aldie pupil constricts due to denervation hypersensitivity With time, there is aberrant regeneration resulting in a hypersensitive near reflex. Initially there is no response to light or accommodation. Lesion of the post ciliary ganglion parasympathetic fibres. The Adie pupil also gets smaller with time 'lil ole Adie' Unilateral dilated pupil that does not react to light and has vermiform iris border movements
Near reflex is ventral so is spared.Īccommodative near reflex intact but light reflex is lost Lesion of dorsal midbrain affects light reflex pathway. Lesion of CN2 between the retina and the pretectal nucleus → light stimulus is not received.īilateral irregular, meiosis that does not react to light, but will accommodate (No constriction to light but will constrict to near objects)
The constricted pupil is the Marcus-Gunn pupil Light to the right eye will not cause constriction, if the light is swung to the right, both eyes will be seen to dilate In right RAPD: Light to the left eye will cause both eyes to constrict. Marcus-Gunn Pupil (Relative afferent pupillary light defect (RAPD))
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