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Abnormalities of pupillary reaction.pptx

eye health education à optometry fans
2 Apr 2023
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Abnormalities of pupillary reaction.pptx

  1. Abnormalities of pupillary reaction Optomety Fans www.optometry.fans
  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.
  3. 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.
  4. 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.
  5. 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
  6. 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.
  7. Causes of mydriasis • Effect of topical parasympatholytic drugs (Atropine, homatropine, tropicamide and cyclopentolate) • Acute congestive glaucoma • Absolute glaucoma • Optic atrophy • Retinal detachment • Internal ophthalmoplegia • 3rd nerve paralysis • Belladonna poisoning
  8. Pupillary reactions • The direct light reflex • The consensual light reflex • Swinging flash light test • The near reflex
  9. 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
  10. 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.
  11. 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.
  12. 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.
  13. Abnormalities of pupillary reaction • Amaurotic light reflex • Efferent pathway defect • Wernicke’s hemianopic pupil • Marcus Gunn pupil • Argyll Robertson pupil (ARP) • The Adie’s tonic pupil
  14. 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.
  15. 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.
  16. 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.
  17. 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
  18. 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.
  19. 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.
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