Anatomy of retina

1. BY: AKSHIT RANA

2.  Retina,the innermost tunic of eyeball, is a
thin ,delicate and transparent membrane ,
which is the most highly developed tissue of
the eye.
 It appears purplish-red due to the visual
purple of the rods and underlying vascular
choroid.,

3. Retina extends from ora-serrata.
It is thickest in the peripapillary
region and thinnest at ora-serrate.
Ora-serrata is the last region where
the retina ends and cilliary body
starts.

4.  Fundus refers to the dome shaped interior of
the eyeball.
 Grossly,fundus can be divided into two
ditinct regions;
1)POSTERIOR POLE
2)ANTERIOR POLE

5.  It refers to the area of fundus posterior to
the retinal equator
 Posterior pole of the retina includes 2
distinct regions:
1)OPTIC DISC
2)MACULA LUTEA

7.  Also called as optic nerve head,pink coloured
 Average diameter of 1.5mm equal to 1DD.
 It is placed 3.4mm nasal to the fovea.
 Photoreceptors are absent here ; hence
known as blind spot
 At the optic disc all the retinal layers
terminate except the nerve fibres,which pass
through the lamina cribrosa to run into the
optic nerve.

8.  A depression seen on the disc is called
physiologicl cup.The central retinal artery
and vein emerge through the centre of this
cup.

9.  It is also called as yellow spot.
 Fovea centralis, is the central depressed part
of macula, it is about 1.5mm in diameter.
 An area about 0.8mm in diameter does not
contain any retinal capillaries and is called
foveal avascular zone.

10.  In this area, there are no rods.
 Cones are tightly packed and it is the most
sensitive part of retina
 It’s central part is called foveola.
 All other retinal layers are absent in this
region.

12.  It refers to the area bounded posteriorly by
the retinal equator and anteriorly by ora
serrata.
 Best examined by indirect opthalmoscopy
and the Goldmann three mirror contact lens
exmanination.

13. 1. PIGMENT EPITHELIUM
2. LAYER OF RODS AND CONES
3. EXTERNAL LIMTING MEMBRANE
4. OUTER NUCLEAR MEMBRANE
5. OUTER PLEXIFORM LAYER
6. INNER NUCLEAR LAYER
7. INNER PLEXIFORM LAYER
8. GANGLION CELL LAYER
9. NERVE FIBRE LAYER
10. INNER LIMITING MEMBRANE

14.  It is theoutermost layer of the retina
 It consist of a single layer of cells containing
the pigment melanin.
 Around the optic disc,they are heaped up as
choroidal ring.
 It ia firmly adherent to the underlying basal
lamina of the choroid.

15.  Rod and Cones are the end organs of vision
and are also known as photoreceptors.
 Rods contain a photosensitive substance
rhodopsin and helps in peripheral vison of
low illumination(scotopic vision)
 Cones also contain a photosensitive
substance and helps in highly discriminatory
central vision(photopic vision) and colour
vision.

16.  It is a fenestrated membrane , on whuch rods
and cones rest and their processes pierce.

17.  It consists of nuclei of the rods and cones.
 Cone nuclei are large and more oval and
carry a layer of cytoplasm.

18.  The innermost portion of each rod and cone
cell is swollen with lateral processes known
as spherules and pedicles respectively.
 This layer consist of connections of rod
spherules and cone pedicles with the
dendrites of bipolar cells and horizontal
cells.

19.  It mainly consists of nuclei of bipolar cells.
 It also contains nuclei of Amarcrine and
Muller’s cells.
 The bipolar cells constitute the first order
neurons in visual pathway.

20.  It essentially consists of connections of
bipolar cells with the ganglion cells and
amacrine cells.

21.  It mainly contains cell bodies of ganglion
cells
 There are 2 types of ganglion cells,
1)MIDGET GANGLION CELLS-present in
macular region
2)POLYSYNAPTIC GANGLION CELLS- lie
predominantly in the peripheral retina.

22.  It consists of axons of ganglion cells, running
parallel to the retinal surface.
 The layer increases in depth as it coverges to
optic disc
 It passes through the lamina cribrosa to form
the optic nerve.

23.  It is the innermost layer and seprates the
retina from the vitreous.
 It is formed by the union of terminal fibres of
the muller’s fibres.
 It is essentially a basement membrane.

24.  Outer 4 layers of the retina-CHOROIDAL
VESSELS.
 Inner 6 layers- CENTRAL RETINAL ARTERY
which is a branch of opthalmic artery .
 Fovera is aavascular but partially gets blood
supply from choroidal vessekls.
 Macula- CENTRAL RETINAL ARTERY and
CILIORETINAL ARTERY.

25.  Central retinal artery emerges from the
centre of the physiological cup of the optic
disc and divides into 4 branches.
 These are END ARTERIES i.e. They do not
anastomose with each other.