THE EYE ANATOMY AND PHYSIOLOGY. MAJOR PARTS OF THE EYE The OUTSIDE EYELID EYELASHES CONJUNCTIVA IRIS...
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Transcript of THE EYE ANATOMY AND PHYSIOLOGY. MAJOR PARTS OF THE EYE The OUTSIDE EYELID EYELASHES CONJUNCTIVA IRIS...
THE EYE
ANATOMY AND PHYSIOLOGY
MAJOR PARTS OF THE EYE
The OUTSIDE EYELID EYELASHES CONJUNCTIVA IRIS CORNEA SCLERA EYE MUSCLES
The INSIDE AQUEOUS HUMOUR LENS (PUPIL) CHOROID RETINA – RODS / CONES VITREOUS HUMOUR FOVEA OPTIC NERVE
MUSCLES OF THE EYE
The Lens
Elastic, circular, biconvex, transparent Held in place by suspensory ligaments It is enclosed in transparent capsule Unique ability – vary its refractive power, by
changing its thickness Ciliary muscle contracts, moves forward,
making lens thicker as it releases tension.
HOW THE EYE SEES
Liquid light
Aqueous humour – is in the anterior and posterior chambers – in the Anterior Segment
Divided by Iris Secreted by Ciliary
glands - continous Passes in front of lens Return via Canal of
Schlemm IO pressure -10-20mmHg
Vitreous humour – Posterior segment
99%water, rest salts and mucoprotien
Maintains pressure to support retina
Maintains shape of eye
Constant through life
The Retina
Innermost layer Made of various light sensitive layers Rods (contrast or night vision) – Rhodopsin
(needs Vit A) Cones (colour vision) Fovea – centre – only cones Optic nerve – convergence of all the nerve
fibres
LACHRYMAL GLANDS AND DUCTS
FOODS THAT HELP
Carrots and other orange foods- beta carotene, vit A Leafy greens - lutein and zeaxanthin—antioxidants that,
studies show, lower the risk of developing macular degeneration and cataracts.
Eggs – zinc and antioxidants Berries and citrus fruit – vitamin C Almonds- Vitamin E Fatty Fish - Tuna, salmon, mackerel, anchovies and trout
are rich in DHA, a fatty acid found in your retina—low levels of which have been linked to dry eye syndrome
DISORDERS OF THE EYE
TRAUMA – blunt, scratch, pierce
VASCULAR – ischemia & haemorrhage
INFLAMMATORY – conjunctivitis, scleritis, iritis, keratitis
CATARACT & GLAUCOMA
SYSTEMIC DISORDERS
DIABETES
HYPERTENSION
THYROID DISORDERS