2. Anatomy of Pupil
• Pupil is a centre aperture of iris about 4-mm to
5 mm diameter called pupil which regulates
the amount of light reaching the retina.
• Pupil is a hole in the iris, and the pupillary area
colour depending upon the condition of the
structures located behind it.
• Pupil normally looks grayish black color.
4. Anatomy of Pupil
• Number : Normally there is only one pupil.
Rarely, there may be more than one pupil. This
congenital anomaly is called polycoria.
• Location. Normally pupil is placed almost in the
centre of the iris. Rarely, it may be congenitally
eccentric is called as corectopia.
• Size : Normal pupil size varies from 3 to 4 mm
depending upon the illumination. But it may be
abnormally small called miosis and large is called
as mydriasis.
6. Anatomy of Pupil
• Shape
• Normal pupil is circular in shape.
• Irregular narrow pupil is seen in iridocyclitis.
• Festooned pupil is the name given to irregular
pupil obtained after patchy dilatation.
• Vertically oval pupil may occur post-operatively
due to incarceration of iris or vitreous in the
wound at 12 O’clock position.
7. Anatomy of Pupil
• Colour
• Pupil is a hole in the iris, but the pupillary area
colour depending upon the condition of the
structures located behind pupil.
• Pupil looks - Greyish black normally
• Jet black - Aphakia
• Greyish white - Immature senile cataract
• Pearly white - Mature cataract
• Milky white - Hypermature cataract
• Brownish black - Cataracta nigra
10. Causes of miosis
• Effect of local miotic drugs.
• Effect of systemic morphine.
• Iridocyclitis.
• Horner’s syndrome.
• Head injury.
• Senile rigid miotic pupil.
• Due to effect of strong light.
• During sleep pupil is pinpoint.
12. Pupillary reactions
• The direct light reflex
• The consensual light reflex
• Swinging flash light test
• The near reflex
13. The direct light reflex
• To elicit this reflex the patient is seated in a
dim lighted room. With the help of a palm one
eye is closed and a narrow beam of light is
shown to other pupil and its response is noted.
• The procedure is repeated for the second eye.
• A normal pupil reacts briskly and its
constriction to light is well maintained
14. The consensual light reflex
• To determine consensual reaction to light, patient
is seated in a dimly-lighted room and the two eyes
are separated from each other by an opaque
curtain kept at the level of nose (either hand of
examiner or a piece of cardboard).
• Then one eye is exposed to a beam of light and
pupillary response is observed in the other eye.
• The same procedure is repeated for the second
eye.
• Normally, the contralateral pupil should also
constrict when light is thrown onto one pupil.
15. Swinging flash light test
• It is performed when relative afferent pathway defect is suspected in
one eye.
• To perform this test, a bright flash light is shone on to one pupil and
constriction is noted. Then the flash light is quickly moved to the
contralateral pupil and response noted.
• This swinging flash light is repeated several times while observing
the pupillary response.
• Normally, both pupils constrict equally and the pupil to which light
is transferred remains tightly constricted.
• In the presence of relative afferent pathway defect in one eye, the
affected pupil will dilate when the flash light is moved from the
normal eye to the abnormal eye. This response is called ‘Marcus
Gunn pupil’ or a relative afferent pupillary defect (RAPD).
• It is the earliest indication of optic nerve disease even in the presence
of normal visual acuity.
16. The near reflex
• In it pupil constricts while looking at a near
object. This reflex is largely determined by the
reaction to convergence but accommodation also
plays a part.
• To determine the near reflex, patient is asked to
focus on a far object and then instructed suddenly
to focus at an object (pencil or tip of index finger)
held about 15 cm from patient’s eye.
• While the patient’s eye converges and focuses the
near object, observe the constriction of pupil.
18. Amaurotic light reflex
• It refers to the absence of direct light reflex on
the affected side and absence of consensual
light reflex on the normal side.
• This indicates lesions of the optic nerve or
retina on the affected side, leading to complete
blindness.
• In diffuse illumination both pupils are of equal
size.
19. Efferent pathway defect
• Absence of both direct and consensual light
reflex on the affected side and presence of both
direct and consensual light reflex on the
normal side indicates efferent pathway defect.
• Near reflex is also absent on the affected side.
• Its causes include : effect of parasympatholytic
drugs (e.g., atropine, homatropine), internal
ophthalmoplegia, and third nerve paralysis.
20. Wernicke’s hemianopic pupil
• It indicates lesion of the optic tract.
• In this condition light reflex (ipsilateral direct
and contralateral consensual) is absent when
light is thrown on the temporal half of the
retina of the affected side and nasal half of the
opposite side; while it is present when the light
is thrown on the nasal half of the affected side
and temporal half of the opposite side.
21. Marcus Gunn pupil
• It is the paradoxical response of a pupil of light
in the presence of a relative afferent pathway
defect (RAPD).
• It is tested by swinging flash light test
22. Argyll Robertson pupil (ARP)
• Here the pupil is slightly small in size and
reaction to near reflex is present but light reflex
is absent.
• Both pupils are involve and dilate poorly with
mydriatics.
• It is caused by a lesion in the region of tectum.
23. The Adie’s tonic pupil
• In this condition reaction to light is absent and
to near reflex is very slow and tonic. The
affected pupil is larger (anisocoria).
• Its exact cause is not known. It is usually
unilateral, and occurs more often in young
women.
• Adie’s pupil constricts with weak pilocarpine
drops, while normal pupil does not.