During a neurological examination, healthcare providers assess pupillary signs as part of a comprehensive evaluation. The following aspects are typically examined:
The following table summarizes the various types of pupillary signs, their definitions, and potential causes:
Table
Type of Pupillary Sign | Definition | Causes |
Mydriasis | Dilation of the pupil (greater than 5 mm). | Sympathetic activation, drug effects (anticholinergics, stimulants), brain herniation, midbrain lesions. |
Miosis | Constriction of the pupil (less than 3 mm). | Parasympathetic activation, opioid use, Horner’s syndrome, pontine lesions. |
Marcus Gunn Pupil | Relative afferent pupillary defect (RAPD) where the affected pupil dilates when light is moved from the unaffected eye to the affected eye. | Optic nerve damage, severe retinal disease. |
Non-reactive Pupils | Pupils that do not constrict in response to light. | Severe brain injury, coma, brain death. |
Anisocoria | Unequal pupil sizes. | Physiological variation, Horner’s syndrome, third cranial nerve palsy, trauma. |
Argyll Robertson Pupil | Small, irregular pupils that constrict with accommodation but not with light. | Neurosyphilis, diabetes, or other central nervous system disorders. |
Pseudo Argyll Robertson Pupil | A pupil that constricts poorly to light but reacts to accommodation, resembling Argyll Robertson but not due to neurosyphilis. | – Diabetes mellitus – Multiple sclerosis – Other neurological conditions |
Aedes Pupil | A small, irregularly shaped pupil that constricts poorly to light but constricts with accommodation. | – Neurosyphilis (Argyll Robertson pupil) – Diabetes mellitus – Other central nervous system disorders |
Accommodation Defect | Loss of the ability to constrict pupils when focusing on a near object. | Lesions affecting the Edinger-Westphal nucleus or other parts of the parasympathetic pathway. |
Pupillary Light Reflex | Both pupils constrict when light is shone in one eye. | Afferent defect (optic nerve damage) or efferent defect (oculomotor nerve palsy). |
Leucocoria | A white reflex from the pupil, often indicating an abnormality. | – Retinoblastoma – Cataracts – Coats’ disease – Retinal detachment |
Parinaud’s Syndrome | A condition characterized by vertical gaze palsy and pupillary light reaction abnormalities. CLUES Mnemonic Convergence retraction nystagmus Light Near Dissociation Upgaze paralysis Eyelid retraction Skew deviation | – Pineal gland tumors – Multiple sclerosis – Stroke affecting the midbrain |
Ophthalmoplegia Interna | A condition where there is paralysis of the muscles controlling pupil size and reaction. | – Diabetes mellitus – Multiple sclerosis – Aneurysms affecting cranial nerves |
Hippus | A rhythmic oscillation of the pupil size, occurring in response to light or accommodation. | – Normal physiological response – Anxiety – Neurological disorders |
Wernicke’s Hemianopic Pupil Reaction | A condition where one pupil reacts to light but not to accommodation, indicating a visual field defect. | – Lesions in the optic tract – Homonymous hemianopia – Stroke affecting the visual pathways |
Hutchinson’s Pupil | A dilated pupil that does not react to light, often indicating increased intracranial pressure. | – Uncal herniation – Brainstem injury – Severe head trauma |
Definition:
Relative Afferent Pupillary Defect (RAPD) is a condition where one pupil does not constrict as much as the other when exposed to light, indicating a problem in the afferent pathway of the affected eye, typically involving the optic nerve or severe retinal disease.
RAPD can result from various conditions, including:
RAPD is assessed using the Swinging Flashlight Test:
