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Pearls & Oy-sters: Anisocoria Greater in the Dark: It’s Not Just All About Horner Pupil

In addition to a Horner pupil, anisocoria can be more pronounced in the dark with physiologic anisocoria, miosis due to posterior iris synechiae, pharmacologic miosis due to a parasympathomimetic agent (i.e., pilocarpine), traumatic miosis, iris ischemia, and a chronic Adie tonic pupil... If the anisocoria is greater in the dark but the miotic pupil does not react to light, this excludes a Horner pupil and expands the differential diagnosis to parasympathomimetic pharmacologic anisocoria, chronic miotic Adie tonic pupil, CN III aberrant regeneration, iris trauma (i.e., traumatic miosis), iris ischemia, or posterior synechiae.

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Articles of Interest

A Case of Bilateral Miosis: Your Diagnosis?

Miosis, like many physical exam findings, can have many causes. When the onset is acute, stroke should always be one of the top considerations, especially when other neurologic symptoms or signs are present. The differential can be further narrowed based on whether miosis is unilateral or bilateral.

Argyll Robertson pupils

A reflex iridoplegia characterized by small, irregular, unequal pupils, with near-light dissociation; absence of a miotic reaction to both direct and consensual light with preservation of the accommodation reflex. Classically associated with neurosyphilis. Rare since the advent of penicillin. Most often found on Medical school exams… Other causes of reflex iridoplegia include Holmes-Adie syndrome, Parinaud syndrome, diabetic neuropathy, brain injury, thiamine deficiency, and mitral regurgitation.

Coma and small pupils

The differential diagnosis of coma with small pupils includes: Non-toxicological causes, toxicological causes...

Horner's Syndrome: What Optometrists Should Know

With classic acquired Horner’s you will see a ptosis and miotic pupil that is more apparent in dim illumination on the affected side. If both these signs are noted, you may inquire about perceived changes in facial sweating, but patients may not always perceive full facial anhidrosis, as earlier mentioned

How to Treat Pinpoint Pupils

Common causes of miosis are medications, drug use (opiates and narcotics), and eye inflammation as a result of trauma or other conditions.

Miosis: What causes constricted pupils?

Miosis is sometimes the result of a rare condition called Horner’s syndrome, which is caused by disruption of the nerve flow on one side of the face, commonly because of a tumor, stroke or spinal cord injury. While some people experience just one symptom, typically, those with Horner’s syndrome have all three of the following signs: Pinpoint pupil on only one side of the face. Ptosis (a drooping upper eyelid over the affected eye). Anhidrosis (an inability to sweat on that same side of the face).

Myosis

Miosis is a totally normal response of the organism to excess light. However, there are some diseases and medications that can cause miotic pupils. Pathological miosis can occur in one or both eyes and persists even in dimly lit places. The causes of pathological miosis are: Motor Reflex Integration Lesions: This can result from bleeding in the brain. Excessive drug use, such as cocaine, methadone, and heroin: when a patient has used heroin, the pupils are so miotic that they are known by the name of "pinpoint" or pinpoint pupils. Some drugs used to treat hypertension and glaucoma.

Pupil Size and the Brain: Exploring the Science of Miosis

Whether it's addressing the underlying condition or discontinuing specific medications, managing miosis requires a tailored approach, highlighting the significance of expert advice for optimal eye health.

Toxin Induced Miosis

Similar to mydriasis, there are two main ways to produce miosis, although we typically think of three: excess muscarinic tone, decreased adrenergic tone, or opioid effect. Muscarinic excess is seen commonly in anticholinesterase drugs, such as with organophosphate or carbamate insecticides. Opioid induced miosis, while typically thought of in its own class, is actually mediated by increased muscarinic tone...

Understanding Eye Miosis: Causes, Symptoms, And Treatment

Various medical conditions affecting the nervous system can result in miosis. Horner’s syndrome, for example, is a rare neurological disorder characterized by a combination of symptoms, including miosis (small pupil), ptosis (drooping eyelid), and anhidrosis (lack of sweating on one side of the face). Similarly, Adie’s tonic pupil is a condition characterized by a unilateral dilated pupil that reacts slowly to light and near stimuli.