Lens/Cataract 2

You are about to perform capsulorrhexis. Which of the following increases the risk of tearing your capsulorrhexis radially?

• Shallowing the AC

• Regrasping the flap near the tear

• Filling the chamber with viscoelastic

• Making your circular capsulorrhexis large

Answer explanation

Shallowing the AC makes the anterior capsule more “convex”, making it easier for tears to “go downhill”

All of the ff can affect A-scan axial length measurements except?

• Silicone oil in vitreous cavity

• Posterior staphyloma

• Flat cornea

• Air in vitreous cavity

Answer explanation

A scan assumes that the anterior chamber is filled with aqueous and the vitreous chamber is filled with vitreous. Any changes in those chambers will result in abnormal A-scan values (unless you change the A-scan settings). Flat corneas have no effect

What is the difference between Limbal Relaxing Incision (LRI) and Astigmatic Keratotomy (AR)?

• LRI - parallel to limbus

  AK - radial to limbus

• LRI - radial to limbus

  AK - parallel

• LRI - closer to limbus

  AK - closer to apex

• LRI - sometime done at sclera

  AK - always done at cornea

Answer explanation

LRI and AK - both are parallel to limbus!

But LRI done very close to limbus while AK is done 1mm from the corneal apex

AK has more effect than LRI

Which of the ff is not associated with the picture shown?

• Corticosteroid use

• Brachytherapy

• Neurofibromatosis type 2

• Wilson’s dx

Answer explanation

Picture shows a posterior subcapsular cataract

Wilson’s dx - sunflower cataract

The ff are associated with the pathophysio of cataract formation except?

• Increase in water insoluble proteins

• Increase in urea insoluble proteins

• Increase in glutathione

• Increase in protein crosslinking

Answer explanation

Glutathione is actually protective of cataract formation