Sl.No. Pg.No. - Notespaedia
Transcript of Sl.No. Pg.No. - Notespaedia
IndexChapterSl.No. Pg.No.
Anatomy and Physiology of Eye
Optics and Refraction
Diseases of Conjunctiva
Diseases of Cornea
Diseases of Sclera
Diseases of Uveal Tract
Diseases of Lens
Glaucoma
Diseases of Vitreous
Diseases of Retina
Neuro-ophthalmology
Disorders of Ocular Motility
Disorders of Eyelids
Diseases of Lacrimal Apparatus
Diseases of Orbit
Ocular Injuries
Lasers and Cryotherapy in Ophthalmology
Systemic and Community Ophthalmology
Instruments
09162441576067
809294109118124132134140143144
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Anatomy and Physiology of EyeDEVElOPMEnt Of EyE
2.6 mm (3 weeks)
3.5 mm (4 weeks) 5.5 to 6 mm10 mm (6 weeks)20 mm (9 weeks)25 mm (10 weeks) 50 mm (3 months)
60 mm (4 months)
230-265 mm (8th month)
265-300 mm (9th month)
- Optic pits appear on either side of cephalic end of forebrain.- Primary optic vesicle invaginates. - Development of embryonic fissure. - Retinal layers differentiate, lens vesicle formed.- Sclera, cornea and extra ocular muscles differentiate.- Lumen of optic nerve obliterated. - Optic tracts completed, pars ciliaris retina grows forwards, pars iridica retina grows forward and lid folds develop.- Hyaloid vessels atrophy, iris sphincter, dilator and ciliary muscles develop.- Fetal nucleus of lens is complete, all layers of retina nearly developed and macula starts differentiation.- Except macula, retina is fully developed, infantile nucleus of lens begins to appear, pupillary membrane and hyaloid vessels disappear. Medulation of optic nerve reaches lamina cribrosa.
Stage of growth Development
Eye at birth and post-natal development
• AP diameter about 16.5 mm (70% of adult size) which is attained by 7- 8 years of age.• Corneal diameter is about 10 mm. Adult size (11.7 mm) is attained by 2 years of age.• Lens is spherical and 3.5 mm thick at birth. Lens grow through out life and become 5 mm thick at 60 years of age.• Macula differentiate 4- 6 months after birth.• Refractive status. New born is hypermetropic by +2to+3D.• Fixation status developing at 1 month and is completed by 6 months.
Infantile nucleus is present.
Reference; Comprehensive Ophthalmology, AK Khurana (Pg 3)
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• Optic vesicle (Neuroectodermal structure) —an outgrowth from the prosencephalon• Lens placode (a specialised area of surface ectoderm) and surrounding surface ectoderm• Mesoderm surrounding the optic vesicle• Visceral mesoderm of maxillary process.
Eyeball and its related structures are derived from
Formation of the optic vesicle and optic stalk
Formation of lens vesicle and optic cup
Developing optic cup surrounded by mesenchyme
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Derivation of various structures of the eyeball
Development of the retina
Development of the crystalline lens
Development of the
eyelids, conjunctiva and lacrimal gland
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Surface ectoderm
• The crystalline lens• Epithelium of the cornea• Epithelium of the conjunctiva• Lacrimal gland• Epithelium of eyelids and its derivatives - cilia, tarsal glands and conjunctival glands• Epithelium lining the lacrimal apparatus.
neural ectoderm
• Retina with its pigment epithelium• Epithelial layers of ciliary body• Epithelial layers of iris• Sphincter and dilator pupillae muscles• Opticnerve(neurogliaandnervouselementsonly)• Melanocytes• Secondary vitreous• Ciliary zonules (tertiary vitreous).
associated paraxial mesenchyme
• Blood vessels of choroid ,iris,ciliary vessels, central retinal artery, other vessels• Primary vitreous• Substantia propria, Descemet’s membrane and endothelium of cornea• The sclera• Stroma of iris• Ciliary muscle• Sheaths of optic nerve• Extraocular muscles• Fat, ligaments and other connective tissue structures of the orbit• Upper and medial walls of the orbit• Connective tissue of the upper eyelid.
Visceral mesoderm of maxillary process below the eye
• Lower and lateral walls of orbit• Connective tissue of the lower eyelid.
StruCturES DEriVED frOM thE EMbryOniC layErS
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ANATOMY OF EYE
• Anteroposterior diameter• Horizontal diameter• Vertical diameter• Circumference• Volume• Weight
24 mm 23.5 mm 23 mm 75 mm 6.5 ml7 gm
Dimensions of an adult eyeball
Poles and equators of the eyeball
PHYSIOLOGY OF EYE
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• Initiation of vision (Phototransduction), - Function of photoreceptors (rods and cones)• Processing and transmission of visual sensation, - Function of image processing cells of retina and visual pathway• Visual perception, - Function of visual cortex and related areas of cerebral cortex.
Physiology of vision
Visual cycle.
Equilibrium between the photodecomposition and regeneration of visual pigments
Light-induced changes in rhodopsin
PHYSIOLOGY OF EYE
Reference; Comprehensive Ophthalmology, AK Khurana (Pg 14 )
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Pathway of light reflex
Retinal fibers
Optic nerveOptic chiasma
Optic tractPretectal nucleus
Ciliary ganglion
Edinger-Westphal nucleus
( III cranial nerve)
Short ciliary nerve
Constrictor pupillae
AfferentFibers
EfferentFibers
Nasal fibers decussate and
cross the optic chiasma.Temporal retinal fibers
remain uncrossed
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