QuizWise 5

Q 1.Which of the following is true about use of cyanoacrylate glue in corneal perforations?
a. Best suited for perforations < 3 mm in diameter
b. Best suited for perforations > 3 mm in diameter
c. Best suited for perforations away from the limbus
d. Both a and c

Q 2. Which of the following is true about fibrin glue?
a. It is a biological adhesive
b. Can be used to seal corneal perforations
c. Has bacteriostatic effect
d. Both a and b

Q 3. What are the mechanisms involved in the action of cyanoacrylate glue in corneal thinning?
a. Prevents  re-epithelisation in the area of corneal thinning
b. Inhibits infiltration of polymorphonuclear leucocytes
c. Disrupts stromal melting
d. All of the above 

Q 4. Which of the following are true about application of cyanoacrylate glue to the area of corneal perforation?
a. The application should be done over a wet surface in a thick layer
b. The application should be done over a dry surface in a thin layer
c. The application should be done over a wet surface in a thin layer
d. The application should be done over a dry surface in a thick layer

5.  Which of the following is FALSE regarding use of conjunctival flaps?
a. Used  in cases with indolent progression and corneal thinning
b. A conjunctival flap brings in superficial blood vessels to promote healing of corneal ulcers therefore preventing the occurrence of corneal perforation
c. Help control pain and delay or avoid invasive surgery
d. Frank perforation is an ideal indication for this procedure

ANSWERS

  1. d. Both a and c.

Use of cyanoacrylate glue is best suited to perforations that measure less than 3 mm in diameter, are concave in profile, and located away from the limbus. The latter due to the poor adhesion that occurs between the glue and the conjunctival tissue, and the tendency for the adhesive to dislodge when applied in this location.

Deshmukh R, Stevenson LJ, Vajpayee R. Management of corneal perforations: An update. Indian J Ophthalmol. 2020;68(1):7‐14.  

DOI: 10.4103/ijo.IJO_1151_19

2. d. Both a and b.

Fibrin glue is a biological tissue adhesive which imitates the final stages of the coagulation cascade when a solution of human fibrinogen is activated by thrombin (the two components of fibrin glue). Fibrin glue includes a fibrinogen component and a thrombin component, both prepared by processing plasma. It can be prepared at a blood transfusion center or from patients own blood or obtained as a commercially available preparation.

Panda A, Kumar S, Kumar A, Bansal R, Bhartiya S. Fibrin glue in ophthalmology. Indian J Ophthalmol. 2009;57(5):371‐379

DOI: 10.4103/0301-4738.55079

Similar to cyanoacrylate glue, fibrin glue has been successfully used in cases with impending as well as frank corneal perforations. The main disadvantage of biological glues is that they start to degrade much faster than cyanoacrylate, have no bacteriostatic effects (like cyanoacrylate), and there is a risk of transmission of prion/ viral diseases with the use of bovine products in its constituents

Jhanji V, Young AL, Mehta JS, Sharma N, Agarwal T, Vajpayee RB. Management of corneal perforation. Surv Ophthalmol. 2011;56(6):522‐538

DOI: 10.1016/j.survophthal.2011.06.003

3. d. All of the above

The application of cyanoacrylate adhesive to an ulcer bed disrupts stromal melting, in both infective and noninfective cases. Large numbers of polymorphonuclear leucocytes, which have potent collagenolytic and proteolytic activity, are present in active corneal ulcers and promote corneal melting. These leucocytes are stimulated by the interaction between re-epithelializing epithelium and the subjacent keratocytes. Cyanoacrylates inhibit re-epithelialization and consequently inhibit the polymorphonuclear leucocytic infiltration in the diseased area.

Deshmukh R, Stevenson LJ, Vajpayee R. Management of corneal perforations: An update. Indian J Ophthalmol. 2020;68(1):7‐14.  

DOI: 10.4103/ijo.IJO_1151_19

4. b. The application should be done over a dry surface in a thin layer.

After debridement of loose epithelium and necrotic material, the perforation site should be as dry as possible, otherwise the cyanoacrylate glue will not stick.

Jhanji V, Young AL, Mehta JS, Sharma N, Agarwal T, Vajpayee RB. Management of corneal perforation. Surv Ophthalmol. 2011;56(6):522‐538

DOI: 10.1016/j.survophthal.2011.06.003

A thin layer application of cyanoacrylate glue is less likely to dislodge. 

5. d. Frank perforation is an ideal indication for this procedure

Conjunctival flaps are used in cases with indolent progression and corneal thinning. A conjunctival flap brings in superficial blood vessels to promote healing of corneal ulcers therefore preventing the occurrence of corneal perforation. The flaps also control pain, eliminate the use of frequent medications, and may provide an alternative to invasive surgery. A conjunctival flap is not appropriate for active suppurative keratitis with marked stromal thinning or in eyes with frank perforation because the leak will continue under the flap.

Jhanji V, Young AL, Mehta JS, Sharma N, Agarwal T, Vajpayee RB. Management of corneal perforation. Surv Ophthalmol. 2011;56(6):522‐538

DOI: 10.1016/j.survophthal.2011.06.003

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