Anatomy Of Sclera

ANATOMY OF SCLERA

Q. 1 Sclera is weakest at all of the follow­ing sites except:
 A Apex
 B Limbus
 C Anteriorly
 D Posteriorly
Q. 1 Sclera is weakest at all of the follow­ing sites except:
 A Apex
 B Limbus
 C Anteriorly
 D Posteriorly
Ans. D

Explanation:

Posteriorly


Q. 2

Blue coloured sclera is frequently associated with:

 A

Osteogenesis imperfecta

 B

Ehler danlos syndrome

 C

Chondrodysplasia

 D

Alport syndrome

Q. 2

Blue coloured sclera is frequently associated with:

 A

Osteogenesis imperfecta

 B

Ehler danlos syndrome

 C

Chondrodysplasia

 D

Alport syndrome

Ans. A

Explanation:

The disorder is frequently associated with blue sclerae, dental abnormalities and progressive hearing loss.


Reference:
Harrisons Principles of Internal Medicine, 18th Edition, Page 3207

Q. 3

Sclera is weakest at the level of:

 A

Macula

 B

Equator

 C

Insertion of extraocular muscles

 D

Ora serrata

Q. 3

Sclera is weakest at the level of:

 A

Macula

 B

Equator

 C

Insertion of extraocular muscles

 D

Ora serrata

Ans. C

Explanation:

Ans. Insertion of extraocular muscles


Q. 4

Blue Sclera is associated with:     

March 2009

 A

Osteogenesis imperfecta

 B

Marfan’s syndrome

 C

Alkaptonuria

 D

All of the above

Q. 4

Blue Sclera is associated with:     

March 2009

 A

Osteogenesis imperfecta

 B

Marfan’s syndrome

 C

Alkaptonuria

 D

All of the above

Ans. D

Explanation:

Ans. D: All of the above

Causes of blue Sclera:

  • Pseudoxanthoma elasticum
  • Osteogenesis imperfecta
  • Ehlers-Danlos syndrome
  • Marf an’s syndrome
  • Alkaptonuria
  • Hypophosphatasia
  • Juvenile paget’s disease
  • Normal in newborns
  • Van der Hoeve’s syndrome

Q. 5

Sclera buckling is used for treatment of ‑

 A

Cataract

 B

Scleritis

 C

Retinal detachment

 D

Vitreous hemorrhage

Q. 5

Sclera buckling is used for treatment of ‑

 A

Cataract

 B

Scleritis

 C

Retinal detachment

 D

Vitreous hemorrhage

Ans. C

Explanation:

Ans. is ‘c’ i.e., Retinal detachment

Treatment of retinal detachment

  • Retinal detachment surgery consists of three components : sealing retinal tears, reducing the vitreous traction on the retina and flattening of retina.
  • It is important to find all retinal tears (holes) and seal them by laser photocoagulation, diathermy or cryoapplication.
  • Scleral buckeling or external plombage or encirclage is a procedure to push the wall of sclera inwards to close the tear, reduce the traction and flatten the retina.
  • Drainage of subretinal fluid helps to flatten the retina against the sclera.
  • Intravitreal surgery (vitrectomy and gas injection) may also be employed.

Q. 6

Thickest portion of sclera is ‑

 A

 Anterior to rectus muscle insertion

 B

Posterior to rectus muscle insertion

 C

Posterior pole

 D

Limbus

Q. 6

Thickest portion of sclera is ‑

 A

 Anterior to rectus muscle insertion

 B

Posterior to rectus muscle insertion

 C

Posterior pole

 D

Limbus

Ans. C

Explanation:

Ans. is ‘c’ i.e., Posterior pole

o The thickness of the sclera varies according to location : ‑

  • At the limbus, the sclera is 0.8 mm thick.
  • Anterior to the rectus muscle insertions, it is 0.6 mm thick.
  • Posterior to the rectus muscle insertions, it is 0.3 mm thick (Thinnest portion).
  • At the equator, it is 0.5 to 0.8 mm thick.
  • At the posterior pole, it is greatest than 1 mm thick.

Q. 7

Thinnest portion of sclera ‑

 A

Anterior to rectus muscle insertion

 B

Posterior to rectus muscle insertion

 C

Posterior pole

 D

Limbus

Q. 7

Thinnest portion of sclera ‑

 A

Anterior to rectus muscle insertion

 B

Posterior to rectus muscle insertion

 C

Posterior pole

 D

Limbus

Ans. B

Explanation:

 Ans. is.b, Posterior to rectus muscle insertion

  • Thinnest portion of sclera→ Posterior to insertions of rectus muscle.
  • Thickest portion of sclera→ Posterior pole.


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