retina class 7th semester
DESCRIPTION
I guess you will like it.TRANSCRIPT
![Page 1: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/1.jpg)
Dr.Narang
Retina
![Page 2: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/2.jpg)
ANATOMY OF RETINA
![Page 3: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/3.jpg)
Gross Anatomy•R
etina extends from the optic disc to the ora serrata.•I
t is divided into two distinct regions: -p
osterior pole and-p
eripheral retina separated by the so called retinal equator.
![Page 4: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/4.jpg)
Posterior pole •I
t refers to the area of the retina posterior to the retinal equator.
•The posterior pole of the retina includes two distinct areas:
-optic disc and
-macula lutea
![Page 5: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/5.jpg)
Macula lutea. •I
t is also called the yellow spot.•I
t is comparatively deeper red than the surrounding fundus and is situated at the posterior pole temporal to the optic disc.
•Fovea centralis is the central depressed part of the macula. It is about 1.5 mm in diameter and is the most sensitive part of the retina. In its Center is a shining pit called foveola.
•An area about 0.8 mm in diameter (including foveola and some surrounding area) does not contain any retinal capillaries and is called foveal avascular zone (FAZ).
•Surrounding the fovea are the parafoveal and perifoveal areas.
![Page 6: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/6.jpg)
Structure of fovea centralis•I
n this area, there are no rods.•C
ones are tightly packed and other layers of retina are very thin.
•Its central part (foveola) largely consists of cones and their nuclei covered by a thin internal limiting membrane.
•All other retinal layers are absent in this region.
•In the foveal region surrounding the foveola, the cone axons are arranged obliquely (Henle’s layer or outer plexiform layer) to reach the margin of the fovea.
![Page 7: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/7.jpg)
Fovea centralis
![Page 8: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/8.jpg)
Peripheral retina It refers to the area bounded posteriorly by the retinal equator and anteriorly by the ora serrata.
![Page 9: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/9.jpg)
Optic disc•I
t is a pink coloured , well-defined circular area of 1.5-mm diameter.
•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.
• A depression seen in the disc is called the physiological cup. The central retinal artery and vein emerge through the centre of this cup.
![Page 10: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/10.jpg)
![Page 11: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/11.jpg)
LAYERS OF RETINA :•M
NEMONIC:•I
N –INTERNAL LIMITING MEMBRANE•N
EW –NERVE FIBER LAYER•G
ENERATION –GANGLIONIC LAYER•I
T –INTERNAL PLEXIFORM LAYER•I
S –INTERNAL NUCLEAR LAYER•O
NLY –OUTER PLEXIFORM LAYER•O
PHTHALMOLOGIST’S –OUTER NUCLEAR LAYER•E
XAMINING –EXTERNAL LIMITING MEMBRANE•P
ATIENTS –PHOTORECEPTORS •R
ETINA –RETINAL PIGMENT EPITHELIUM
![Page 12: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/12.jpg)
Internal limiting membrane•I
t is the innermost layer and separates the retina from vitreous.
•It is formed by the union of terminal expansions of the Muller’s fibres.
•It is essentially a basement membrane.
![Page 13: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/13.jpg)
Nerve fibre layer (stratum opticum) •I
t consists of axons of the ganglion cells, running parallel to retinal surface.
•The layers increase in depth as it converges to optic disc.
•The nerve fibers are fine and non-medullated
•It pass through the lamina cribrosa to form the optic nerve
![Page 14: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/14.jpg)
Ganglion cell layer•I
t mainly contains the cell bodies of ganglion cells (the second order neurons of visual pathway).
• There are two types of ganglion cells:
- The midget ganglion -cells are present in the macular region. each such cell synapses with single bipolar cell.
- Polysynaptic ganglion -cells lie predominantly in peripheral retina .Each such cell may synapse with upto a hundred bipolar cells
![Page 15: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/15.jpg)
Inner plexiform layer•I
t essentially consists of connections of bipolar cells with the ganglion cells and amacrine cells.
![Page 16: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/16.jpg)
Inner nuclear layer•I
t mainly consists of nuclei of bipolar cells. •I
t also contains nuclei of amacrine and Muller’s cells •C
apillaries of central artery of retina, but outer layers are avascular.
•The bipolar cells constitute the first order neurons.
![Page 17: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/17.jpg)
Outer plexiform layer•T
he Innermost portion of each rod and cone cell is swollen with lateral processes known as spherules and pedicles respectively.
•This layer consists of connections of rod spherules and cone pedicles with the dendrites of bipolar cells and horizontal cells.
![Page 18: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/18.jpg)
Outer nuclear layer•I
t consists of nuclei of the rods and cones.•C
one nuclei are larger and more oval and carry a layer of cytoplasm
![Page 19: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/19.jpg)
External limiting membrane•I
t is a fenestrated membrane, on which rods and cones rest and their processes pierce
![Page 20: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/20.jpg)
Photoreceptor layer•
Rods and cones are the end organs of vision and are also known as photoreceptors.
•Rods contain a photosensitive substance visual purple (rhodopsin) and subserve the peripheral vision and vision of low illumination (scotopic vision).
• Cones also contain a photosensitive substance and are primarily responsible for highly discriminatory central vision (photopic vision) and colour vision.
![Page 21: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/21.jpg)
Pigment epithelium. •I
t is the outermost layer of retina.•I
t consists of a single layer of cells containing pigment.•T
he cells of RPE contain varying amount of melanin.•C
ells are taller at fovea and contain more pigment.•A
round the Optic disc they are heaped up as ‘choroidal ring’•I
t is firmly adherent to the underlying basal lamina (Bruch’s membrane) of the choroid.
![Page 22: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/22.jpg)
Blood supply•O
uter four layers of the retina- choroidal vessels•I
nner six layers- central retinal artery, which is a branch of the ophthalmic artery.
![Page 23: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/23.jpg)
CRAO•C
entral retinal artery emerges from centre of the physiological cup of the optic disc and divides into four branches.
•These are end arteries i.e., they do not anastomose with each other.
![Page 24: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/24.jpg)
Predisposing factors:•H
ypertension•C
ardiovascular diseases
![Page 25: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/25.jpg)
Etiology•T
hrombophilic disorders.•E
mboli from the carotid artery and those of cardiac origin(20%)
•Atherosclerosis-related thrombosis at the level of lamina cribrosa(75%).
•Arteritis with obliteration.
•Angiospasm
•Raised intraocular pressure
![Page 26: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/26.jpg)
Symptoms :•S
udden,painless loss of vision.•A
maurosis fugax
![Page 27: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/27.jpg)
Sign’s•R
ed reflex absent.•M
arked narrowing of large arteries, arterioles invisible.•W
ithin few hours retina become milky white because of oedema.•W
ithin a day or two macular area show cherry red spots because of choroid shining through thin retina.
•When obstruction is incomplete, column of venous blood has cattle tract appearance.
•After few weeks oedema subsides , atrophic changes occur(optic nerve atrophy/attenuated thread like arteries).
•No PL/PR
![Page 28: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/28.jpg)
Treatment•I
mmediate lowering of IOP –massage /IV mannitol /A.C. paracentesis .
•Vasodilator and inhalation of mixture of 5%CO2 and 95%O2.
•Anticoagulants –IV heparin
•IV steroids –giant cell arteritis
![Page 29: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/29.jpg)
Prognosis:•>
6 hours –No return of central vision.
![Page 30: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/30.jpg)
CRVO•T
he retinal veins: These follow the pattern of the retinal arteries.
•The central retinal vein drains into the cavernous sinus directly or through the superior ophthalmic vein
![Page 31: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/31.jpg)
Predisposing Factors•A
ge :6th/7th decade(2nd decade in case of non ischaemic)•S
ystemic hypertension•R
aised IOP•D
iabetes•H
yperviscosity syndrome•P
eriphlebitis
![Page 32: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/32.jpg)
Pathogenesis•E
xternal compression on the vein•V
enous stasis•D
egenerative disease of venous endothelium
![Page 33: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/33.jpg)
Types:•N
on Ischaemic/Venous stasis retinopathy/Partial CRVO=75%•I
shchaemic CRVO/haemorrhagic CRVO/Complete CRVO=25%
![Page 34: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/34.jpg)
Non Ischaemic Symptom:•V
ague U/L fogginess of vision initially.•V
/A remains good.•V
itreous hemorrhage never present•M
ild pupillary defect
![Page 35: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/35.jpg)
Signs:•M
ild tortuosity and dilatation of retinal veins.•D
ot and blot and flame shaped haemorrhage.•O
ptic disc swelling•M
acular oedema may or not- permanent impaired vision but normally 50% regain VA as Macular oedema resolves.
•Circulating IgM raised in most,leading to phlebitis of central vein in optic head ,hence fundus picture resemble venous thrombosis
![Page 36: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/36.jpg)
Ischaemic CRVO Symptoms :•V
A- marked reduced
![Page 37: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/37.jpg)
Signs•M
arked tortuosity and engorged retinal veins.•M
assive superficial and deep haemorrhages.•C
otton wool exudates.•O
ptic disc swelling and hyperaemia.•M
acular oedema and haemorrhage.•B
unches of tortuous new vessels formed upon optic disc.•E
ventual atrophy of affected retina.•F
undus described as BLOOD AND THUNDER FUNDUS•O
bstruction of central vein just behind lamina cribrosa ,peripheral at bifurcation as in arterisclerotic
![Page 38: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/38.jpg)
Prognosis:•5
0% develop rubeosis and neovascular glaucoma within 3 months of initial occlusion aka 90 days glaucoma.
•Pre-retinal or vitreous haemorrhage secondary to NVD
![Page 39: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/39.jpg)
Management•I
t is usually not required.•T
he condition resolves with almost normal vision in about 50 percent cases.
•Visual loss in rest of the cases is due to chronic cystoid macular oedema, for which no treatment is effective.
•However, a course of oral steroids for 8-12 weeks may be effective.
•Patient should be followed up closely for rubeosis iridis, as prompt treatment in early cases by PRP.
![Page 40: Retina class 7th semester](https://reader037.vdocuments.us/reader037/viewer/2022102823/546cd217af7959ec228b5260/html5/thumbnails/40.jpg)
THANKS FOR PATIENCE…!