OCULAR ANTOMY

1. ANATOMY OF UVEA

2. UVEAL TRACT
• THIS IS THE INTERMEDIATE VASCULAR COAT OF THE EYEBALL CONSISTING OF THE THREE
FOLLOWING PARTS;
- IRIS,
- CILIARY BODY AND
- CHOROID.

3. IRIS
• IT IS THE MOST ANTERIOR PART LYING IN FRONT OF THE CRYSTALLINE LENS AND BEHIND THE
CORNEA.
• IT IS CIRCULAR IN SHAPE WITH A CENTRAL OPENING CALLED PUPIL (LIKE A DIAPHRAGM OF A
CAMERA).
• IT IS PERIPHERALLY ATTACHED TO THE MIDDLE THE ANTERIOR SURFACE OF THE CILIARY BODY.
• ANTERIOR SURFACE OF THE IRIS IS DIVIDED BY A RIDGE CALLED COLLARETTE (THICKEST PART)
INTO SMALLER PUPILLARY ZONE AND LARGER CILIARY ZONE.
• THE COLLARETTE IS FORMED BY ROUGHLY CIRCULAR SERIES OF RIDGES AND MINOR ARTERIAL
CIRCLE OF IRIS.
• THE PECULIARITY OF THE IRIS VESSELS IS THAT, THEY USUALLY DO NOT BLEED WHEN THE IRIS IS
CUT. THIS IS DUE TO THE FACT THAT THEY ARE ENCLOSED BY THICK COLLAGEN BUNDLES.

5. HISTOLOGY
• IT CONSIST OF 4 LAYERS:
• A. ANTERIOR ENDOTHELIUM—IT IS CONTINUOUS WITH THE CORNEAL ENDOTHELIUM.
- IRIS CRYPTS OF FUCHS ARE PIT-LIKE DEPRESSIONS OF THE IRIS CAUSED BY THE FOCAL ABSENCE OF
ANTERIOR ENDOTHELIUM.
- THESE CRYPTS ARE PRESENT NEAR COLLARETTE AND THE ROOT OF THE IRIS.
• B. STROMA— THE SPHINCTER PUPILLAE MUSCLE, VESSELS AND NERVES OF THE IRIS AND PIGMENT
CELLS ARE EMBEDDED IN THE CONNECTIVE TISSUE OF THE STROMA.
• C. POSTERIOR MEMBRANE—IT CONSISTS OF A THIN LAYER OF UNSTRIATED AND INVOLUNTARY
MUSCLE FIBRES, CALLED DILATOR PUPILLAE. DILATOR PUPILLAE IS ARRANGED RADIALLY NEAR THE
ROOT OF THE IRIS
- CONTRACTION OF THE DILATOR PUPILLAE DRAWS THE PUPILLARY MARGIN TOWARDS THE CILIARY
BODY TO CAUSE DILATION OF THE PUPIL.
• D. POSTERIOR EPITHELIUM—IT CONSISTS OF TWO LAYERS OF PIGMENTED EPITHELIUM.

7. FUNCTION OF THE IRIS
• THE CENTRAL OPENING OF THE IRIS, I.E. PUPIL REGULATES THE ENTRY OF LIGHT INTO THE EYE
THROUGH THE ACTIONS OF THE DILATOR PUPILLAE AND THE SPHINCTER PUPILLAE MUSCLES.

8. BLOOD SUPPLY
• IT IS FROM THE MINOR AND MAJOR ARTERIAL CIRCLE OF THE IRIS.

9. NERVES SUPPLY
• A. SPHINCTER PUPILLAE—OCULOMOTOR (IIIRD CRANIAL) NERVE
• B. DILATOR PUPILLAE—NERVES FROM THE CERVICAL SYMPATHETIC
• C. SENSORY—NASOCILIARY NERVE [A BRANCH OF 1ST DIVISION OF THE TRIGEMINAL (VTH
CRANIAL) NERVE].

10. CILIARY BODY
• IT IS THE INTERMEDIATE PART OF THE UVEAL TRACT.
• IT EXTENDS FROM ORA SERRATA TO THE ROOT OF THE IRIS, WHERE IT IS ATTACHED TO THE
SCLERAL SPUR
•

11. • IT IS DIVIDED INTO TWO ANATOMICAL PARTS: A. PARS PLICATA:
- THE CILIARY PROCESSES ARE ACTIVELY INVOLVED IN THE SECRETION OF THE AQUEOUS HUMOUR.
- B. PARS PLANA: THIS PART IS SMOOTH AND EXTENDS UPTO ORA SERRATA. DURING THE OPERATIONS OF
VITRECTOMY AND LENSECTOMY, PORTS ARE MADE IN THIS AREA DUE TO RELATIVE AVASCULARITY AND
IT’S LOCATION AWAY FROM THE CRYSTALLINE LENS.
• CILIARY MUSCLES FORM THE CHIEF MASS OF THE CILIARY BODY
• ACCOMMODATION

13. FUNCTIONS OF THE CILIARY BODY
• A. PRODUCTION OF AQUEOUS HUMOUR
• B. IT IS INVOLVED IN ACCOMMODATION:
• C. INCREASE OUTFLOW OF AQUEOUS THROUGH THE TRABECULAR MESHWORK:
• D. INNER NONPIGMENTED LAYER OF THE EPITHELIUM SECRETES HYALURONIC ACID, THE
ESSENTIAL COMPONENT OF THE VITREOUS HUMOUR.

14. BLOOD SUPPLY
• IT IS SUPPLIED BY TWO LONG POSTERIOR CILIARY ARTERIES AND SEVEN ANTERIOR CILIARY
ARTERIES VIA MAJOR ARTERIAL CIRCLE OF IRIS.

15. NERVE SUPPLY
• I. CILIARY MUSCLE— IT IS SUPPLIED BY THE OCULOMOTOR (IIIRD CRANIAL) NERVE AND THE
SYMPATHETIC NERVE.
• II. SENSORY— NASOCILIARY BRANCH OF THE TRIGEMINAL (VTH CRANIAL) NERVE

16. CHOROID
• IT IS A HIGHLY VASCULAR THIN TUNIC LOCATED BETWEEN THE SCLERA AND THE RETINA AND
EXTENDS FROM ORA SERRATA TO OPTIC NERVE.
• IT CONSISTS OF FOUR LAYERS FROM OUTSIDE INWARDS :
- A. SUPRACHOROIDAL LAMINA
- B. LAYER OF BLOOD VESSELS I. OUTER LARGER VESSEL LAYER (HALLER’S LAYER)
II. INNER SMALLER VESSEL LAYER (SATTLER’S LAYER).
- C. CHORIOCAPILLARIES— IT IS A LAYER OF CAPILLARY PLEXUS OF FENESTRATED VESSELS AND
IT NOURISHES OUTER HALF OF THE RETINA.
- D. MEMBRANE OF BRUCH—IT IS AVASCULAR, SEPARATING CHORIOCAPILLARIES FROM THE
PIGMENT EPITHELIUM OF THE RETINA.

17. FUNCTIONS OF THE CHOROID
• A. IT PROVIDES BLOOD SUPPLY AND NUTRITION TO THE RETINAL PIGMENT EPITHELIUM (RPE)
AND OUTER HALF OF THE SENSORY RETINA.
• B. IT REGULATES OCULAR TEMPERATURE.

18. • ARTERIAL SUPPLY : IT IS SUPPLIED BY THE FOLLOWING GROUP OF ARTERIES:
- I. SHORT POSTERIOR CILIARY ARTERIES (20 IN NUMBER)
- II. LONG POSTERIOR CILIARY ARTERIES (2 IN NUMBER)
- III. ANTERIOR CILIARY ARTERIES (7 IN NUMBER)
• VENOUS DRAINAGE VENOUS BLOOD FROM THE IRIS, CILIARY BODY AND CHOROIDS IS
COLLECTED BY A SERIES OF INTERMEDIATE SMALL VEINS, WHICH DRAIN INTO VORTEX VEINS
(USUALLY 4 IN NUMBER).

19. QUESTION BANK

20. • ALL OF THE FOLLOWING ARE PART OF UVEA EXCEPT:
• A. PARS PLICATA
• B. PARS PLANA
• C. CHOROID
• D. SCHWALBE’S LINE

21. • THE ANTERIOR AND POSTERIOR CHAMBER OF THE EYE ARE SEPARATED BY:
• A) ANTERIOR LENS CAPSULE
• B) POSTERIOR LENS CAPSULE
• C) IRIS DIAPHRAGM
• D) AQUEOUS HUMOUR

22. • NUMBER OF INTRAOCULAR MUSCLES IN THE EYE
• A. 2
• B. 3
• C. 4
• D. 6

23. • WHICH OF THE FOLLOWING IS NOT AN INTRINSIC MUSCLE IN EYE
• A. SPHINCTER PUPILLAE
• B. DILATOR PUPILLAE
• C. CILIARY MUSCLE
• D. INFERIOR OBLIQUE

24. • . NOT A PART OF MIDDLE VASCULAR COAT OF THE EYE
• A. IRIS
• B. CHOROID
• C. CILIARY BODY
• D. LAMINA CRIBROSA

25. • WHAT IS REGARDED AS THE VASCULAR TUNIC OF THE EYE?
• A)CORNEA
• B) SCLERA
• C) CONJUNCTIVA
• D) CHOROID

26. • AQUEOUS HUMOUR IS SECRETED BY
• A. ANGLE OF ANTERIOR CHAMBER
• B. CHOROID
• C. CILIARY BODY
• D. IRIS

27. • VORTEX VEIN DRAIN
• A. IRIS AND CILIARY BODY
• B. SCLERA
• C. UVEAL TRACT
• D. RETINA

28. • MINOR ARTERIAL CIRCLE IS PRESENT ON
• A. PUPILLARY BORDER
• B. COLLARETTE
• C. WITHIN THE IRIS STROMA
• D. AT THE ROOT OF IRIS

29. • BRUCH’S MEMBRANE IS LOCATED ON
• A. CORNEA
• B. CONJUNCTIVA
• C. IRIS
• D. RETINA

30. • THE MAIN VEINS DRAINING THE CHOROIDS IS:
• A) ORBITAL VEINS.
• B) VORTEX VEINS.
• C) POSTERIOR CILIARY VEINS.
• D) CENTRAL RETINAL VEIN.

31. • 25 FUNCTION OF CILIARY BODY
• A. ACCOMMODATION
• B. AQUEOUS PRODUCTION
• C. BOTH
• D. NONE