Thread: Ophtha Mcqs

Code:

choose true & false ......sp pay attention on each option 

1. The cornea 
a Has an endothelial layer that regenerates readily. 
b Comprises three layers. 
c The endothelium actively pumps water from the stroma. 
d Is an important refractive component of the eye. 
e Has a stroma composed of randomly arranged collagen fibrils. 



 
2. The retina 
a Is ten layers thick. 
b Has ganglion cells whose axons form the optic nerve. 
c Has three types of rods responsible for colour vision. 
d The neuroretina is firmly attached to the retinal pigment epithelium. 
e The RPE delivers vitamin A for rhodopsin production. 




3. The lens 
a Grows throughout life. 
b Is surrounded by a collagenous capsule. 
c Cortical and nuclear fibres are nucleated. 
d Has a high refractive index owing to its protein content. 
e Changes in shape with accommodation. 




4. The suspensory ligament of the lens (the zonule) 
a Attaches the lens to the ciliary body. 
b Is part of the iridocorneal angle. 
c Is composed of smooth muscle. 
d Transmits changes in tension to the lens capsule. 


 
5. The posterior chamber 
a Is another name for the vitreous body. 
b Lies between the iris, lens and ciliary body. 
c Contains aqueous humour, secreted by the ciliary processes. 
d Is in communication with the anterior chamber. 





6. The tear film 
a Is 100 μm thick. 
b Is composed of four layers. 
c The mucin layer is in contact with the cornea. 
d Is important in the refraction of light entering the eye. 
e Contains lysozyme and secretory IgA. 



 
7. The iridocorneal angle 
a Is the site of aqueous production. 
b Lies between the cornea and the ciliary body. 
c In primary open angle glaucoma there is a reduction in the number of cells covering 
the trabecular meshwork. 
d Fluid passes through the trabecular meshwork to Schlemm’s canal. 



 
8. The optic nerve 
a Axons leave the eyeball through the cribriform plate. 
b Is not bathed in CSF until it enters the cranial cavity. 
c Anteriorly is supplied by blood from the ciliary arteries. 
d Axons are not myelinated in its retrobulbar part. 
e Is formed by the nerve fibre layer of the retina. 




 
9. The third, fourth and sixth cranial nerves 
a All originate in the midbrain. 
b A nuclear third nerve palsy will cause a contralateral palsy of the superior 
rectus. 
c The fourth nerve supplies the lateral rectus. 
d The sixth nerve has a long intracranial course. 
e The third nerve may be affected by aneurysms of the posterior communicating artery.

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Code:

1. The cornea 
a False. The human endothelium does not regenerate; dead cells are replaced by 
the spreading of surviving cells. 
b True. The cornea has epithelial, stromal and endothelial layers. 
c True. The endothelial cells pump out ions and the water follows osmotically.Removal of water maintains corneal transparency. 
d True. The cornea is a more powerful refractive element than the natural lens of the eye. 
e False. The fine, equally spaced, stromal collagen fibrils are arranged in parallel and packed in an orderly manner. This is a requirement for transparency. 


2. The retina 
a True. 
b True. The retinal ganglion cell axons form the retinal nerve fibre layer and exit the eye at the optic nerve head. 
c False. The rods are responsible for night vision and three cone types are responsible for daylight and colour vision. 
d False. The attachment is loose; the neuroretina separates in retinal detachment. 
e True. Vitamin A is delivered by the RPE to the photoreceptors and combined with opsin. 


3. The lens 
a True. 
b True. This is of great importance in cataract surgery. 
c False. The older, deep cortical and nuclear fibres lose their nuclei and other organelles. 
d True. 
e True. 


4. The suspensory ligament of the lens (the zonule) 
a True. Zonular fibres extend from the pars plicata of the ciliary body to the lens 
equator. 
b False. The zonule lies behind the iris and iridocorneal angle. 
c False. The ciliary muscle contains smooth muscle, not the zonule. 
d True. Contraction of the ciliary muscle relaxes the zonular fibres allowing the lens 
to increase its curvature and thus its refractive power (this is ‘accommodation’). 


5. The posterior chamber 
a False. The vitreous body is quite separate. 
b True. 
c True. 
d True. Communication is via the pupil, in the gap between iris and lens at the 
pupil margin. If this gap is narrowed or closed, pressure in the posterior chamber 
pushes the iris forward and may close the angle (acute closed angle glaucoma). 

 
6. The tear film 
a False. The tear film is 3 μm thick. 
b False. The tear film is composed of mucin, aqueous and oil layers. 
c True. 
d True. It provides a smooth interface for the refraction of light. 
e True. 


7. The iridocorneal angle 
a False. It is the site of aqueous drainage. 
b True. 
c True. 
d True. The process is active. 


8. The optic nerve 
a True. 
b False. In the orbit, within its sheaths, the optic nerve is surrounded by subarachnoid 
CSF in continuity with that in the intracranial cavity. 
c True. This is a most important blood supply for the anterior optic nerve. 
d False. They are usually not myelinated within the eye. 
e True. It is made up from retinal ganglion cell axons. 


9. The third, fourth and sixth cranial nerves 
a False. The nucleus of the sixth nerve lies in the pons. 
b True. The superior rectus is innervated by the contralateral nucleus. 
c False. It supplies the superior oblique. 
d True. This makes the sixth nerve susceptible to trauma, which may cause lateral rectus 
palsy. 
e True. It passes lateral to the artery.

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Thank u