CASE REPORT  
Tadpole Pupil: A Very Rare Entity  
Royala Zaka1, Muhammad Moeez-ud-Din2, Mirza Zaki-ud-Din Ahmed Sabri3, Zunair Aziz4  
1,2,3,4Prevention of Blindness, A Trust Based Hospital, Karachi  
ABSTRACT  
Tadpole Pupil is a very rare clinical entity. Only few cases have been reported to date in the literature. This is the  
first case reported in Pakistan to the best of our knowledge. A 19-year old female came with the complaint of  
repeated episodes of 2 to 3 times per week of irregular shaped pupil with blurry vision that subsided itself in few  
minutes within an hour. At presentation, her examination showed normal VA of 6/6 in both eyes with normal  
pupillary reactions in light and dark. Color vision, contrast, visual fields by confrontation, extraocular movements  
were all normal. Ophthalmic and neurologic examination was also unremarkable. Her condition was not  
associated with Horner syndrome, Adies or Migraine which were excluded after examination. She was counseled  
about the benign nature of her condition and advised for regular follow up or report in case of new appearance of  
symptoms.  
Key Words: Tadpole pupil, Horner syndrome, Adies Pupil.  
How to Cite this Article: Zaka R. Tadpole Pupil: A Very Rare Entity (A Case Report). Pak J Ophthalmol. 2020;  
36 (3): 302-304.  
Doi: 10.36351/pjo.v36i3.1061  
INTRODUCTION  
CASE REPORT  
First described in 1912 by Erlenmeyer1, the term  
“tadpole pupil”was coined by Thompson in 1983. It is  
characterized by spontaneous intermittent segmental  
dilation of the pupil2. Thompson presented the largest  
number of these cases. Only few cases have been  
described in literature to date2-4. It most commonly  
occurs in young healthy females but 2 pediatric cases  
have been found recently5,6. Usually it is unilateral and  
any segment of the iris can be involved and appears as  
tadpole. The cause for this condition is unknown but  
some associations are found with Horner syndrome,  
Adie’s pupil and migraine2. Patient can present with  
only pupil distortion to blurry vision, headache,  
peculiar sensation and dizziness.  
A 19 – year old female came with the complaint of  
painless irregular shape of her left pupil that became  
tear-shaped or pear shaped for few minutes within an  
hour for 2 to 3 times per week. She had this complaint  
for the previous 2 years. The pupil returned to its  
normal shape with regain of normal vision. The patient  
complained of recurrent mild blurry vision during this  
period. Her episodes remitted itself and reappeared  
after every 3 to 4 weeks. It was not associated with  
haloes, headache, syncope, drooping of eyelids or loss  
of sweating. There were no relieving or aggravating  
factors for the episodes.  
The patient herself took the pictures during her  
episodes. Her examination showed normal VA of 6/6  
Correspondence to: Royala Zaka  
Prevention of Blindness, A Trust Based Hospital, Karachi  
Email: drroyala@hotmail.com  
Received: May 2, 2020  
Accepted: May 4, 2020  
Revised: May 4, 2020  
Fig. 1: Tadpole pupil left eye after 35 min during the episode.  
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Pakistan Journal of Ophthalmology, 2020, Vol. 36 (3): 302-304  
Tadpole Pupil: A Very Rare Entity  
Fig. 2: Normal Shape of Left Pupil after an Episode.  
in both eyes with normal pupillary reactions in light  
and dark. Color vision, contrast, visual fields by  
confrontation, extraocular movements were all normal.  
Ophthalmic and neurologic examination was also  
unremarkable.  
pupil. Since its not known whether the tadpole pupil or  
Horner syndrome precedes, the importance is to  
diagnose such a rare case and exclude its associations  
like Horner that can be life threatening. It points to the  
significance of this case. As our patient had no  
associations till now, we counseled her for the benign  
nature with reinforcement of the regular follow-up.  
10% Phenylephrine did not show any change in  
pupil size. A diagnosis of left tadpole pupil was made  
and patient was reassured about the benign nature of  
her condition that was not associated with Horner’s  
syndrome.  
CONCLUSION  
Since tadpole pupil itself is a benign condition but all  
patients should be checked for Horner syndrome  
because of its high association with it. This can save  
the patient from life threatening condition associated  
with Horner’s syndrome.  
DISCUSSION  
Most of the data available by Thompson, who  
described 26 cases, reveals that tadpole pupil is usually  
a spontaneous unilateral condition and the side and the  
peaked iris segment of the pupil involvement can be  
different at different times of episodes. Although most  
cases have been found in young females for few  
minutes and mostly without any systemic association  
but Aggarwal et al described 2 year old girl with  
tadpole pupil associated with congenital Horner  
syndrome5. Similarly, Weir et al described 2 year old  
boy with this pupillary abnormality during  
uncomplicated strabismus surgery6. Hansen et al.  
presented atypical case of a 12 year old girl who  
developed tadpole pupil after physical exercise7.  
Vijayaraghavan et al presented a case of 19-year old  
boy who had bilateral tadpole pupil with reference to  
seizures associated with hyponatremia8. The reason of  
the tadpole pupil is not known but these atypical cases  
suggest the presence of different pathophysiology.  
Since tadpole pupil is frequently seen with Horner  
syndrome3 as compared to the general population, it  
may be because of denervation hypersensitivity of iris  
dilator muscle. Lee et al9 excluded it by doing Horner  
Syndrome by using phenylephrine test. We did the  
same in our patient. Tadpole pupil is also found to be  
associated with migraine and Adies pupil but that was  
not the case with our patient. The iris dilator muscle is  
the muscle that shows segmental spasm10 in tadpole  
Conflict of Interest  
Authors declared no conflict of interest.  
Author’s Designation and Contribution  
Royala Zaka; Ophthalmologist: Study design,  
manuscript writing, literature review, critical review.  
Muhammad Moez Uddin; Ophthalmologist: Study  
design, literature review, critical review.  
Zaki Uddin Ahmed Sabri; Ophthalmologist: Study  
design, literature review, critical review.  
Zunair Aziz; Ophthalmologist: Study design, literature  
review, critical review.  
REFERENCES  
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Auftreten einer wandernden Pupille. Berlin Klin Wschr.  
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2. Udry M, Kardon R, Sadun F, Kawasaki A. The  
Tadpole Pupil: Case Series with Review of the  
Literature and New Considerations. Front Neurol. 2019;  
10: 846. Doi. Org/10.3389/Fneur.2019.00846.  
3. Thompson HS, Zackon DH, Czarnecki JSC.  
Tadpole-shaped pupils caused by segmental spasm of  
Pakistan Journal of Ophthalmology, 2020, Vol. 36 (3): 302-304  
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Royala Zaka, et al  
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L, Yeakley JW. Unilateral pupillary distortion: a case  
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JAMA Neurology. 74 (4): 481-.  
6. Weir RE, Hajdu SD, Greaves BP. Transient tadpole  
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