Human eye: viva questions with answer

Human eye:

1. How many layers of eye present from outside to inside? 

Ans: outside to inside: fibrous coat ( sclera and cornea ) , vascular coat( iris, ciliary body, choroid , nervous coat (retina)

2. how many layers present in cornea?

Ans: outside to inside

• lining epithelium: non-keranized stratified squmous epithelium 
• Bowman's membrane 
• substantia propria 
• Descemet's membrane 
• corneal endothelium 

3. Mention the name of neurons in retina 

Ans: Rods and cone cells, Amacrine, bipolar neuron, ganglionic cells

4. How optic nerve is formed?

Ans:  by axon of ganglionic cells

5. Mention the name of muscles present within the iris ?

Ans : sphincter pupillae and dilator pupillae

6. Mention the secretomotor pathway of the lacrimal gland 

Ans: the preganlionic fibres start in the lacrimatory nucleus(lower pons)
pass through nervus intermedius
the geniculate ganglion
the greater petrosal nerve
the nerve of pterygoid canal
pterygopalatine ganglion
post ganglionic fibres from pterygopalatine ganglion passage through zygomatic nerve
zygomaticotemporal nerve
lacrimal nerve
lacrimal gland

7. Mention the content of orbital cavity.

Ans: Content of orbit

1. eyeball 
2. two fascia : orbital and bulbar fascia 
3. extraocular muscles
4. Lacrimal glands
5. Artery: ophthalmic 
6. Veins: superior and inferior ophthalmic vein 
7. Nerves: sensory : optic nerve and ophthalmic nerve (branches of trigeminal nerve)            Motor: oculomotor(3rd cranial nerve), trochlear nerve (4th cranial nerve) and abducent nerve (6th cranial nerve) 
8. Ganglion : ciliary 
9. Orbital fat 

8. Give nerve supply of extraocular muscles

Ans: SO 4 , LR 6 and rest 3
 Trochlear nerve :Superior oblique
Abducent nerve: Lateral rectus
oculomotor nerve : medial, superior and inferior rectus and inferior oblique muscle

9. Mention the name of branches of ophthalmic artery

Ans: ophthalmic artery is the branch of internal carotid artery
its branches are:

1. central artery of retina 
2. supraorbital and supratrochlear artery 
3. anterior and posterior ethmoidal artery 
4. posterior ciliary artery
5. medial palpebral artery 
6. muscular artery 
7. lacrimal artery 

10. Why cornea is transparent ? 

Ans: Cornea is transparent. Because

• it is avascular 
• melanin absent in corneal epithelium
• in substantia propria, bundles of collagen fibrils (not fibre) and long slender fibroblasts are parallel in arrangement 
• The transparency of cornea requires precise regulation of the water content of the stroma, this function regulate by corneal endothelium , if water contain of cornea reduces , it causes aggregation of collagen fibres so cornea become opaque