Transcript Retina and Vitreous

Retina and
Vitreous
Retina
Retina
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The innermost layer of the eyeball.
It is extremely thin and transparent
(0.5mm)
It contains visual receptors of the eye
The retinal neurons transmit the picture
through the optic nerve fibers to brain
for perception
Layer of retina
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There are 10 layers in the retina
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Retinal pigment epithelium
Layer of rods and cones
External limiting membrane
Outer nuclear layer
Outer plexiform layer
Inner nuclear layer
Inner plexiform layer
Ganglion cell layer
Nerve fibre layer
Internal limiting membrane
Retinal receptors
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The retinal receptors are divided into two main populations
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Rods
Cones
Cones
Rods
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Function best in dim light
There are 125million rods
in the retina
Rods are relatively poor in
visual details
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Function best in daylight
There 6 million cones in
the retina
Cones enable us to see
small visual details
Helps to visualize the
colors
Fovea and ora serrata
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The cones form a concentrated area in the retina known
as fovea
It lies in the center of the macula lutea
The junction of the periphery of the retina and ciliary body
is called ora serrata
Vitreous
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The Vitreous humour is a transparent gel that provides a
clear optical medium.
It is helps to keep the three layers apposed to each other
It occupies approximately 80% of the volume of the globe.
The vitreous consist of water, collagen fibrils, molecules of
hyaluronic acid, peripheral cells and mucopolysacharides
forming a gel like material.
It nourishes lens, ciliary body and the retina.
Examination of vitreous
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Examination of the anterior vitreous can be carried out with slitlamp.
The vitreous should be observed for cells and any opacities.
Changes in the vitreous with age
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Between 40 and 70 years of age in
most individuals and earlier in
myopes, vitreous liquefaction or
syneresis occurs.
The vitreous mass gradually shrinks
and collapse, causing its separation
from the retina, a condition known as
posterior vitreous detachment .(PVD).
Condensation of the vitreous fibrils
are present within this liquefied
vitreous are visible as floaters.
Retinal Diseases
Diabetic Retinopathy
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It is now a major cause of blindness
in retina.
Patient who is suffering from diabetic
mellitus
Classification
– Non proliferative diabetic retinopathy
(NPDR)
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Micro aneurysms
Hemorrhages
Hard exudates
Retinal odema
– Proliferative diabetic retinopathy
(PDR)
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New vessels at the disc
Fibrovascular bands
Vitreous detachment
Vitreous hemorrhage
Investigations and Treatment
– Urine and Blood Sugar examination
– FFA (Fundus flourescein angiography)
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Management
Medical Treatment :
Good diabetic control
Laser Treatment
Photocoagulation to stop leaking from
retinal vessels and bleeding from new
vessels
Vitrectomy is done in case of vitreous
hemorrhage, traction retinal
detachment
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Surgical Treatment :
Hypertensive Retinopathy
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Vascular Changes in the retina associated with
systemic hypertension
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Grade I
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Grade II
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Marked generalized narrowing
associated with focal
narrowing of arterioles
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Grade III
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Grade II changes and also
hemorrhage cotton wool spots
and hard exudates
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Grade IV
- All changes of grade III plus
papillodema
Mild generlaised narrowing of
arterioles in small branches
Management:
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No special management is required for the
retinopathy as most of the changes are
reversible with adequate control of blood
pressure
Retinal detachment
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Separation of retina from the retinal
pigment epithelial layer
Myopia
Retinal Degeneration
Trauma
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Floaters
Flashes of light
Sudden painless loss of vision
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Scleral buckling procedure
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Retinitis pigmentosa
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It is a hereditary condition of the
retina affecting the rods
Features
– Night blindness
– Tubular vision : advanced cases
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Fundus changes:
– Waxy pallor of disc
– Narrowed vessels
– Bony spicule pigmentation
Treatment
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No permanent cure at present
Supportive treatment
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Vitamin A
Low vision aids
Visual rehabilitation
Genetic counselling
Affected individuals discouraged to have kids
Central Serous retinopathy (CSR)
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IT id due to detachment of retina in the
macular region due to accumulation of
fluid resulting in defective vision
Sudden onset of painless loss of vision
Central scotoma
Micropsia (object appears small)
Metamorphopsi (object irregularity)
Mild elevation of macular area
Foveal reflex absent
Reassurance
Long standing cases : laser
photocoagulation
Retinoblastoma
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It is a malignant tumour of the retina occuring in children
under 5 years
White reflex over the pupil
Squint
Radiation therapy, chemotherapy
Photocoagulation
Cryotherapy
Enucleation/excentration
Vitreous hemorrhage
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Bleeding into the vitreous
Blood vessels in to retina
Causes
Trauma to the eye
Diseasea of the blood
vessels
Diabetic retiopathy
Inflammation of the retinal
veins
Diseases of retina
Retina tears
Retinal detachment