Retina

Question 1

Definition

Answer 1

Innermost tunica of the eyeball, is a thin, delicate and transparent membrane

Question 2

Extent

Answer 2

From the optic to the Ora serrata

Question 3

Surface are

Answer 3

266mm2

Question 4

Thickest and thinnest

Answer 4

Peripapillary region and Ora serrate

Question 5

Grossly divided into 2 distinct regions

Answer 5

Posterior pole and peripheral retina separated by the so called retinal equator

Question 6

Retinal equator

Answer 6

It is an imaginary line which is considered to lie in line with the exit of the 4 vena verticose

Question 7

Posterior pole

Answer 7

Area of retina posterior to retinal equator
Two distinct areas: optic disc and macula lutea
Posterior pole is best examined by slit lamp indirect bio microscopy using +78D and +90D lens and by direct ophthalmoscopy

Question 8

Optic disc

Answer 8

It is a pink colored, well defined vertically oval area. It is placed 3.4 mm nasal to the fovea.
Optic nerve head- beginning of the optic nerve
Physiological cup- depression seen in disc

Question 9

Macula lutea

Answer 9

It is also called the yellow spot.
Situated at the posterior pole temporal to the optic disc.
Fovea centralis is the central depressed part of the macula- most sensitive part of macula- contains only cones- lowest threshold for light and highest visual acuity.
Foveola- shining pit in center
Umbo- tiny depression in center of foveola

Question 10

Peripheral retina

Answer 10

Area bounded posteriorly by the retinal equator and anteriorly by the Ora serrata

Question 11

Microscopic structure

Answer 11

10 layers:
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 fiber layer
Internal limiting membrane

Question 12

Functional division of retina

Answer 12

Temporal retina and nasal retina

Question 13

Blood supply

Answer 13

Outer four layers of retina- avascular and get their nutrition from the choroidal and vascular system formed by contribution from anterior ciliary arteries and posterior ciliary arteries

Inner six layers- central retinal artery branch of ophthalmic artery

Question 14

Venous drainage

Answer 14

Retinal veins. The central retinal vein drains into the cavernous sinus directly or through the superior ophthalmic vein.
The only place where the retinal system anastomoses with ciliary system is in the region of lamina cribrosa