1. Retina and Vitreous
Retina

2. Retina 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

3. Layer of retina There are 10 layers in the retina
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

4. Retinal receptors * The retinal receptors are divided into two main populations * Rods * Cones
Function best in daylight
There 6 million cones in the retina
Cones enable us to see small visual details
Helps to visualize the colors
Rods
Function best in dim light
There are 125million rods in the retina
Rods are relatively poor in visual details

5. Fovea and ora serrata
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

6. Vitreous
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.

7. Examination of vitreous
Examination of the anterior vitreous can be carried out with slit-lamp.
The vitreous should be observed for cells and any opacities.

8. Changes in the vitreous with age
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.

9. Retinal Diseases

10. Diabetic Retinopathy It is now a major cause of blindness in retina.
Patient who is suffering from diabetic mellitus
Classification
Non proliferative diabetic retinopathy (NPDR)
Micro aneurysms
Hemorrhages
Hard exudates
Retinal odema
Proliferative diabetic retinopathy (PDR)
New vessels at the disc
Fibrovascular bands
Vitreous detachment
Vitreous hemorrhage

11. Investigations and Treatment
Urine and Blood Sugar examination
FFA (Fundus flourescein angiography)
Management
Medical Treatment : Good diabetic control
Laser Treatment : Photocoagulation to stop leaking from retinal vessels and bleeding from new vessels
Surgical Treatment : Vitrectomy is done in case of vitreous hemorrhage, traction retinal detachment

12. Hypertensive Retinopathy
Vascular Changes in the retina associated with systemic hypertension
Grade I Mild generlaised narrowing of arterioles in small branches
Grade II Marked generalized narrowing associated with focal
narrowing of arterioles
Grade III - Grade II changes and also hemorrhage cotton wool spots and hard exudates
Grade IV - All changes of grade III plus papillodema
Management:
No special management is required for the retinopathy as most of the changes are reversible with adequate control of blood pressure

13. Retinal detachment
Separation of retina from the retinal pigment epithelial layer
Myopia
Retinal Degeneration
Trauma
Floaters
Flashes of light
Sudden painless loss of vision
Scleral buckling procedure

14. Retinitis pigmentosa
It is a hereditary condition of the retina affecting the rods
Features
Night blindness
Tubular vision : advanced cases
Fundus changes:
Waxy pallor of disc
Narrowed vessels
Bony spicule pigmentation

15. Treatment No permanent cure at present Supportive treatment Vitamin A
Low vision aids
Visual rehabilitation
Genetic counselling
Affected individuals discouraged to have kids

16. Central Serous retinopathy (CSR)
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

17. Retinoblastoma
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

18. Vitreous hemorrhage 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