Retina
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Transcript of Retina
Retina A thin transparent and delicate membrane which is the innermost layer of the eyeball.
It extends from optic disc to ora serrata.
Grossly it is divided into
Posterior pole
Peripheral retina
Posterior pole includes two areas
Optic disc
Macula lutea
Optic disc
Optic disc: a well defined circular area of 1.5-2mm diameter.
Here all the retinal layers terminate except the nerve fibres
A depression is seen in the disc called as Physiological cup
Significance of physiological cup: the central retinal arteyand vein emerge through the centre of this cup
Macula lutea
Also called as the Yellow Spot
It is about 5.5 mm in diameter
Fovea centralis is the central deeper part of macula (1.5mm in diameter) which is the most sensitive part of the retina
In its centre a shining pit called foveola is located
Internal limiting membrane
Nerve fibre layer
Ganglion cell layer
Inner plexiform layer
Inner Nuclear layer
Outer plexiform layer
Outer nuclear layer
External limiting membrane
Layers of rods and cons
Retinal Pigmented epithelium
Functional division of retina
Temporal retina Nasal retina
Nerves arising from temporal retinaPass through optic nerve and optic tract of same side to terminate in Ipsilateral
Geniculate body
Nerves arising from nasal retinaPass through optic nerve cross in
optic chiasma and travel to contra lateral optic tract and eliminate in
contra lateral geniculate body
Blood supply
Outer four layers are supplied by choroidal vessels
Inner six layers are supplied by central retinal artery , a
branch of Ophthalmic artery
Disease of retina
Congenital and
developmental disorders
Inflammatory disorders
Vascular disorders
Macular disorders
Dystrophy and degenerative
disorders
Retinal detachment
Tumors
Congenital and developmental disorders
Anomalies of optic disc
Crescents
Situsinversus
Congenital pigmentati
on
Coloboma
Drusen
Hypoplasiaof optic
disk
Anomalies of nerve fibres
Medullated/opaque nerve
fibres
Anomalies of vascular elements
Persistent hyaloidartery
Congenital tortuosity of
retinal vessels
Anomalies of Retina proper
Albinism
Night blindness
Day blindness
Oguchidisease
Retinal cyst
Retinal detachmen
t
Colobomaof fundus
Anomalies of macula
Aplasia
Hypoplasia
coloboma
Coloboma of optic disc• Cause: due to failure of closure of embryonic
fissure
• Occurs in two forms:
Minor coloboma
Fully developed coloboma
Inflammatory disorders of the retinaRetinitis
Non specific
• Acute purulent: occurs as metastatic infections from patients having pyaemia resulting in endopthalmitis or panopthalmitis
• Subacute retinitis of Roth: occurs in patients suffering from SubAcute Bacterial Endocarditis. characterized by multiple superficial retinal hemorraghes,involving posterior part of fundusthey have a white spot in centre.blurred vision is the symptom
Specific
• Bacterial
• Viral
• Mycotic
• parasitic
Retinal vasculitis/Eales’ disease
• Clinical features:
– Sudden appearing
floaters(black spots
infront of the eyes)
– Painless loss of
vision(due to vitreous
hemorrhage)
Inflammation of retinal vessels
Eales’ disease is idiopathic inflammation of peripheral retinal veins
Characterized by recurrent vitreous hemorrahe
Etiology: hypersensitivity reaction to tubercular protein
• Stage of inflammation
• Stage of Ischemia
• Stage of retinal neovascularization
• Stage of sequelae
Clinical stages of the
disease
• Treatment
• Oral corticosteroids
• Laser photo
coagulation
• Vitreo retinal
surgery
(CRAO) CENTRAL RETINAL
ARTERY OCCLUSION
Signs and symptoms• Central retinal
artery occlusions cause sudden, acute, and painless loss of vision in one eye.
Central retinal artery occlusion (CRAO) is a disease of the eye where the flow of blood through the central retinal artery is blocked (occluded). There are several different causes of this occlusion, the most common is carotid artery atherosclerosis.
Fundoscopic exam will show a red lesion, called a
"cherry red spot," with surrounding pale retina (the pale color is caused
by ischemia of the retina)
• The Undersea and Hyperbaric Medical Society lists Central Retinal Artery Occlusion (CRAO) as an approved indication for Hyperbaric Oxygen Therapy.[3] This a treatment for CRAO that is covered by medical insurance in North America. Existing treatments include ocular massage, anterior chamber paracentesis, and inhalation therapy of a mixture of 5% carbon dioxide and 95% oxygen