• 12 SECTION Disorders Pupil

Mydriatic Pupil of Traumatic Iridoplegia

Key Facts

•Mydriatic, usually oval or serrated pupil resulting from damage to iris sphincter and/or stroma

•Affected pupil displays impaired constriction to light and to a near target

•History of direct eye trauma, intraocular surgery, or anterior chamber inflammation usually present

•Slit-lamp examination usually discloses iris abnormalities

•Topical pharmacologic tests can be used to exclude other conditions

Clinical Findings

•Mydriatic, oval, or serrated pupil

•Sometimes iris sphincter tears, stromal atrophy, transillumination defects, synechiae

•Sometimes evidence of anterior chamber angle recession

Differential Diagnosis

•Tonic pupil

•Mydriatic pupil of third cranial nerve palsy

•Pharmacologically dilated pupil

•Horner syndrome

Ancillary Testing

•Topical instillation of 1/10% pilocarpine causes no constriction of affected pupil

•Topical instillation of 1% pilocarpine may cause segmental constriction of affected pupil

Treatment

• None

Prognosis

• Condition likely to be stable

A

B

C

D

E

Fig. 12.7 (A) In darkness, the right pupil is dilated and oval because of segmental iris damage. (B) In brightness, the right pupil does not constrict but the left pupil constricts normally. (C) When a target is viewed at reading distance, the right pupil does not constrict but the left constricts normally. (D) After instillation of 1/10% pilocarpine, neither pupil constricts. (E) After instillation of 1% pilocarpine, the right pupil constricts segmentally and the left pupil constricts normally.

Iridoplegia Traumatic of Pupil Mydriatic

• 12 SECTION Disorders Pupil

Episodic Pupil Dilation

Key Facts

•Temporary (<12 h) anisocoria without other neuro-ophthalmic signs

•Patient may complain of blurred vision, difficulty focusing on near target, headache

•Most common in young or middle-aged women

•Considered a dysautonomic manifestation (parasympatholytic or sympathomimetic) often associated with migraine or seizure

•Examination sometimes shows elongated pupil (tadpole pupil)

•No need for work-up

Clinical Findings

•Anisocoria with normally reactive pupils or mydriatic pupil that constricts relatively poorly to light

•Affected pupil may be elongated (tadpole pupil)

•No other neuro-ophthalmic findings

•May occur in conjunction with migraine-like headache or following a seizure

Ancillary Testing

•Pupil pharmacologic testing not necessary if anisocoria has resolved

•No need for neuroimaging in typical cases, even if no history of migraine or seizure

Differential Diagnosis

• Resolving pharmacologically dilated pupil

Treatment

• None

Prognosis

• Episodes may recur

A

B

C

D

E

F

Fig. 12.8 Episodic right pupil dilation. (A) In darkness, the right pupil is larger than the left. (B) In brightness, the right pupil does not constrict normally. (C) When a target is viewed at reading distance, the right pupil does not constrict normally. (D) Instillation of 1/10% pilocarpine fails to constrict either pupil. (E) Instillation of 1% pilocarpine constricts both pupils. (F) Twenty four hours later, the pupils are of equal size.

Dilation Pupil Episodic

• 12 SECTION Disorders Pupil

Physiologic (Simple, Benign, Essential)

Anisocoria

Key Facts

•Anisocoria of <1 mm in dim illumination attributed to normal variation

•Mechanism unknown

•May be intermittent, and larger pupil may switch sides

•Both pupils constrict normally to light

•No iris pathology or exposure to topical autonomically active drugs

•No pharmacologic signs of iris dilator muscle denervation

Clinical Findings

•Anisocoria of <1 mm in dim illumination

•Pupils constrict normally to light

•No pupil dilation lag when ambient light turned off

•No pharmacologic signs of iris dilator muscle denervation

•No other pertinent neuro-ophthalmic findings

Ancillary Testing

•<1 mm anisocoria after instillation of cocaine 10%

•No change in anisocoria after instillation of apraclonidine 0.5%

Differential Diagnosis

•Horner syndrome

•Occult iris pathology

Treatment

• None

Prognosis

• Anisocoria may be intermittent, and larger pupil may switch sides

A

B

C

Fig. 12.9 Physiologic anisocoria. (A) In darkness, right pupil is larger than left pupil. (B) In brightness, both pupils constrict normally. (C) After instillation of 10% cocaine, both pupils dilate normally.

Anisocoria Essential) Benign, (Simple, Physiologic