MCQs - Principles of Ophthalmic Surgery

Question 1

For the surgical preparation of a site for a superficial keratectomy which of the following agents would be recommended?

a. A 1:50 dilution of chlorhexidine (without alcohol) and sterile saline to flush
b. A 1:10 dilution of chlorhexidine (without alcohol) for the skin, a 1:50 dilution of povidone iodine solution for the conjunctival sac and sterile saline to flush
c. Povidone iodine solution diluted to 1:10 for the skin and 1:50 for the conjunctival sac plus flushing with sterile saline
d. Povidone iodine solution diluted to 1:10 for the skin and 1:50 for the conjunctival sac plus flushing with sterile water

Answer 1

For the surgical preparation of a site for a superficial keratectomy which of the following agents would be recommended?

c.Povidone iodine solution diluted to 1:10 for the skin and 1:50 for the conjunctival sac plus flushing with sterile saline

Well done. Chlorhexidine is not a suitable agent for ocular disinfection so povidone iodine is preferred. Saline is more physiological than water and so is a better agent for the final flush.
d.Povidone iodine solution diluted to 1:10 for the skin and 1:50 for the conjunctival sac plus

Question 2

Question 2
Define tarsorrhaphy.

a. A surgical procedure to shorten the eyelid margin
b. The fused eyelids present at birth
c. Adhesions of the eyelids to the conjunctiva
d. A surgical procedure to partially close the eyelid margins

Answer 2

Define tarsorrhaphy.

d.A surgical procedure to partially close the eyelid margins

Question 3

Question 3
The depth of placement for corneal sutures is critical to achieve a successful surgical outcome. With a full thickness corneal wound how deep should the sutures be placed?

a. 3 / 4 stromal depth
b. 1 / 2 stromal depth
c. 2 / 3 stromal depth
d. 1 / 3 stromal depth

Answer 3

The depth of placement for corneal sutures is critical to achieve a successful surgical outcome. With a full thickness corneal wound how deep should the sutures be placed?

c.2 / 3 stromal depth

Well done. It is important that sutures are placed sufficiently deeply to provide structural support, and 2/3 depth is considered appropriate

Question 4

Sharp incisions are a frequently employed method of surgical cutting. They are most accurate in what tissue type?

a. Loosely arranged tissue such as the cornea
b. Firm tissue with fibres which are easily displaced by a cutting action
c. Loosely arranged tissue such as the conjunctiva
d. Firm tissue with fibres which are cut rather than displaced by an incision

Answer 4

Sharp incisions are a frequently employed method of surgical cutting. They are most accurate in what tissue type?

d.Firm tissue with fibres which are cut rather than displaced by an incision

Question 5

You are presented with a 5 year old terrier cross with an acutely painful right eye following a walk in the woods. On ophthalmic examination you note a corneal foreign body. The pupil is miotic but no dyscoria is present, nor can any hyphaema be appreciated. From this limited information, what is your assessment of the depth of this foreign body?

a. It is impossible to tell the depth of the material without anaesthetising the patient and examining under an operating microscope
b. It is likely to be penetrating the anterior stroma
c. It is likely to be perforating the cornea
d. It is likely to be very superficial and easy to remove under topical anaesthesia alone

Answer 5

You are presented with a 5 year old terrier cross with an acutely painful right eye following a walk in the woods. On ophthalmic examination you note a corneal foreign body. The pupil is miotic but no dyscoria is present, nor can any hyphaema be appreciated. From this limited information, what is your assessment of the depth of this foreign body?

b.It is likely to be penetrating the anterior stroma

The correct answer is: It is likely to be penetrating the anterior stroma

Question 6

dyscoria -

Answer 6

An abnormality in the shape of the pupil.

Question 7

Question 6
What magnification of surgical loupes would be most appropriate for performing replacement of a prolapsed nictitans gland in a 14 week old bulldog puppy?

a. 2.5 x magnification
b. 4.0 x magnification
c. 6.0 x magnification
d. No magnification is required

Answer 7

Question 6
What magnification of surgical loupes would be most appropriate for performing replacement of a prolapsed nictitans gland in a 14 week old bulldog puppy?

b.4.0 x magnification
Well done. Although there is obviously some personal preference a moderate magnification is normally recommended and for general purpose adnexal surgery such as this 4-0 is the most widely used magnification

Question 8

Question 7
Which of the following choices would be the most appropriate forceps to grasp the conjunctiva in a patient which is conscious, but has had topical anaesthesia applied to the conjunctival sac, in order for you to take a snip biopsy of the conjunctiva?

a. Von Graefe forceps
b. Colibri forceps
c. Bennet’s cilia forceps
d. St Martins tying forceps

Answer 8

Which of the following choices would be the most appropriate forceps to grasp the conjunctiva in a patient which is conscious, but has had topical anaesthesia applied to the conjunctival sac, in order for you to take a snip biopsy of the conjunctiva?

a.Von Graefe forceps

Well done. Forceps need to have teeth to allow grasping of the conjunctiva but without tearing it. This is the only instrument on this list with this design.

Question 9

Question 8
The choice of suture and needle is very important in all ophthalmic surgery. Which of the following would be most suitable to repair a corneal wound when using 4.0 x magnification operating loupes?

a. 8-0 polyglactin on a taper point needle
b. 6-0 polyglactin on a spatula tipped needle
c. 10-0 nylon on a spatula tipped needle
d. 8-0 polyglactin on a spatula tipped needle

Answer 9

d.8-0 polyglactin on a spatula tipped needle

Well done. For corneal surgery a spatula tipped needle is required and 8-0 is the largest gauge which should be used in the cornea

Question 10

Question 9
You are about to perform an enucleation and wish to use a retrobulbar nerve block to assist analgesia for the procedure. Which anaesthetic agents would you use?

a. Bupivacaine and tetracaine
b. Lidocaine and bupivacaine
c. Proxymetacaine and bupivacaine
d. Proxymetacaine and lidocaine

Answer 10

You are about to perform an enucleation and wish to use a retrobulbar nerve block to assist analgesia for the procedure. Which anaesthetic agents would you use?

b.Lidocaine and bupivacaine

Well done. It is recommended to use a combination of drugs which have both a rapid onset and longer lasting effect, which this combination provides. Proxymetacaine and tetracaine are topical rather than injectable agents and therefore not appropriate.