Paper One: MACVSc



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Australian College of Veterinary Scientists

Fellowship Examination

June/July 2008

Veterinary Ophthalmology

Written Paper 1

Basic sciences and principles

Perusal time: twenty (20) minutes

Time allowed: three (3) hours after perusal

Section A: short answer questions

Allow one (1) hour

Answer all twenty (20) questions

All questions within this section are of equal value

Subsections of questions within this section are of equal value

Section B: essay questions

Allow two (2) hours

Answer only four (4) of the five (5) questions

All questions within this section are of equal value

Subsections of questions within this section are of equal value

Paper 1 — Veterinary ophthalmology

Section A — short answer questions. Answer all twenty (20) questions.

1. Name four (4) structures in the eye derived from neural ectoderm.

2. Answer both the following:

a) Briefly outline the normal development of the optic cup after formation of the optic vesicle. Failure of what process leads to development of an optic nerve coloboma.

b) Name two (2) other clinical abnormalities associated with failure of this process.

3. Answer both the following:

a) Name the two (2) layers of the tear film that are important for the stability of the tear film. What are the origins of these layers in dogs?

c) The functions of Harder’s gland in the rabbit are still unknown. List four (4) functions that have been attributed to this gland in the rabbit.

4. Making a correct diagnosis in clinical ophthalmology often depends on manipulating the light source and angle of incidence with a slit lamp. Briefly outline the use of focal direct illumination and direct retroillumination in slit lamp biomicroscopy.

5. Answer all the following:

a) What is the average drop volume delivered by most ophthalmic bottle solutions (to the closest five (5) microlitres)?

d) What is the volume of the tear film compartment in the dog?

e) What is the approximate volume that the palpebral fissure can hold in the dog?

f) What pH is necessary for ophthalmic solutions, to minimise irritation of the ocular surface?

Continued over page

6. One family of genes is thought to be particularly important in embryogenesis and organogenesis in the eye.

a) What is this family?

g) How many gene members have been identified in the family? Choose from:

– 3 genes

– 6 genes

– 9 genes

– 12 genes.

h) Which gene from this family is most commonly associated with eye development?

i) Is optic nerve myelination a prenatal or postnatal event?

7. Answer both the following:

a) What is the reason for the development of the ciliary body processes? Provide an example of a lower vertebrate that does not have ciliary processes.

j) Approximately how many millimetres from the limbus is the ora ciliaris retinae located in the dorsal aspect of the canine eye? Is the ora ciliaris retinae located further from the limbus dorsally or laterally in the canine eye?

8. Draw an outline of the canine iridocorneal angle and label the major structures.

9. The production and composition of aqueous humour is important for the normal function and nutrition of tissues in anterior chamber of the eye.

a) Which is the most common cation found in aqueous humour and what proportion of the cations present does this represent?

b) Name two (2) of the anions found in aqueous humour.

Continued over page

10. Angiogenesis is tightly controlled in ocular tissues with loss of control implicated in several ocular diseases. With respect to factors important in regulating angiogenesis, answer all the following:

a) What is the proposed role of angiostatin?

k) Which of the following species does not produce angiostatin in the corneal epithelium:

– cattle

– horse

– dog

– rat.

l) One of angiostatins receptors, integrin avb3, is present in the retina of the dog. Is this true or false?

m) Angiostatin is an internal fragment of which protein?

11. With respect to the histology of the horse conjunctiva in health and disease, answer all the following:

a) What is the epithelial cell type found in conjunctiva near the limbus (bulbar)?

n) Where is the highest concentration of lymphoid cells in the equine conjunctiva?

o) Which of the following is the most common epithelial cell type in the equine conjunctival epithelium, based on brush cytology smears:

– deep

– cylindrical

– intermediate.

a) Periodic acid–Schiff (PAS) staining shows that the equine conjunctiva contains a population of mucous cells with no characteristics of goblet cells. What percentage of mucous cells did not have characteristics of goblet cells? Choose from the following:

– 15–20%

– 20–25%

– 25–30%

– 30–35%.

Continued over page

12. With respect to postnatal development of axial globe length using B-scan ultrasonography, answer all the following:

a) At what age did axial globe length begin to plateau? Choose from the following ages:

– 10 weeks

– 15 weeks

– 20 weeks

– 25 weeks.

p) What was the reported period of most rapid growth? Choose from the following:

– 2–9 weeks

– 10–17 weeks

– 18–25weeks

– 26–33 weeks.

q) What was the mean axial globe length in millimetres at 52 weeks? Choose from the following lengths:

– 15.13mm

– 17.54mm

– 19.52mm

– 21.12mm.

r) The study found a significant difference in axial globe length in males compared with females. Is this true or false?

13. The maintenance and repair of the corneal stromal extracellular matrix require a tightly coordinated balance of extracellular matrix synthesis, degradation and remodelling. Answer all the following:

a) List a common matrix metalloproteases implicated in the degradation and remodelling of the corneal stromal collagen.

s) List another common matrix metalloprotease implicated in the degradation and remodelling of the corneal stromal collagen.

t) Which matrix metalloprotease is found only in wounded corneas?

u) List two (2) natural protease inhibitors found in the precorneal tear film or the cornea.

Continued over page

14. Answer all the following:

a) Briefly define the term ‘ammetropia’.

v) Briefly define the term ‘astigmatism’.

w) What is the accommodative power of the dog?

x) What term is used to describe the spectrum of colour vision in dogs?

15. There are many features of fish eyes which differ to the canine eye. List four (4) unique features of fish eyes.

16. Answer both the following:

a) Camelids do not have meibomian glands. Instead, what gland produces the lipid layer of the tear film in camelids?

y) Camelids have a high incidence of ocular disease. List four (4) ophthalmic conditions seen in camelids.

17. Atropine sulfate 1% drops applied to the equine eye may dilate the pupil for a prolonged period. With one application of atropine sulphate 1% drops:

a) What is the maximum period the pupil could remain dilated in a healthy equine?

z) What breed is reported to be more sensitive to the pharmacological effects of atropine? Choose from

- Arabian

- Thoroughbred

- Appaloosa

- Warmblood?

aa) Over what period should maximal pupillary dilation be achieved?

ab) Which sex appears to be more sensitive to these prolonged effects?

18. Name the nerve(s) that innervates the following:

– superior eyelid levator

– superior oblique muscle

– cornea

– orbicularis muscle.

Continued over page

19. The equine eye displays at least eight adaptations to an open-range habitat. List four (4) of these adaptations.

20. Photodynamic therapy (PDT) is a relatively new treatment that is used in veterinary ophthalmology. Briefly describe the process involved and one indication for its use in veterinary ophthalmology.

Section B over page

Section B — essay questions

Answer four (4) from the following five (5) questions only.

1. Answer both the following:

a) Bacterial infections can have significant consequences for the eye. Discuss various antibiotic classes found in topical ophthalmic solutions available in Australia. In your discussion, include the spectrum of activity for three (3) antibiotic families. You should also discuss the common Gram-negative and Gram-positive bacterial isolates in health and disease of the ocular surface.

ac) How would you diagnose and approach bacterial infections in the ocular tissues listed below and what antibiotic would you choose? Justify your choice, including factors that influence drug levels in the affected tissues.

– conjunctiva

– cornea

– vitreous humour.

2. Aqueous humour is particularly important in providing nutrition to several intraocular structures. Discuss the process of aqueous humour production. Your discussion should include the main contributors to aqueous humour production and any chemical reactions, as well as the major differences between aqueous humour and blood. You should also mention aqueous changes in ocular inflammation and the implications for the tissues using aqueous humour as their source of nutrients.

3. The blood supply to the eye is important for ocular health and normal function. What are the major arterial and venous supplies to the uveal tract (posterior and anterior) and retina? Discuss vascular permeability and autoregulation in these areas, including factors implicated in autoregulation of blood flow. Discuss the pathophysiology and clinical signs of systemic hypertension in the cat with specific reference to autoregulation and vascular permeability.

4. Describe the anatomy and morphology of the canine retina potentially with the help of a diagram and compare and contrast with the avian retina (with specific reference to the raptor). Refer in more detail to the function of three (3) of the retinal layers in either the canine or avian retina.

5. The equine cornea plays a vital role in normal function of the eye. Discuss how the cornea contributes to normal function and describe the anatomy of the normal equine cornea. Your discussion should include the function of the different layers and detail with regards to the thickness and specific cell and collagen types found.

End of paper

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Australian College of Veterinary Scientists

Fellowship Examination

June/July 2008

Veterinary Ophthalmology

Written paper 2

Clinical practice and applications

Perusal time: twenty (20) minutes

Time allowed: three (3) hours after perusal

Section A: short answer questions

Allow one (1) hour

Answer all twenty (20) questions

All questions within this section are of equal value

Subsections of questions within this section are of equal value

Section B: essay questions

Allow two (2) hours

Answer only four (4) of the five (5) questions

All questions within this section are of equal value

Subsections of questions within this section are of equal value

Paper 2: Veterinary ophthalmology

Section A — short answer questions

Answer all twenty (20) questions.

1. With respect to keratoconjunctivitis sicca in the juvenile Yorkshire terrier:

a) What is the usual Schirmer tear test result in these dogs?

ad) What is the proposed aetiopathogenesis for the condition?

ae) Are females or males predisposed?

af) What is another proposed aetiopathogenesis for keratoconjunctivitis sicca?

2. With respect to lens-induced uveitis in dogs with cataracts:

a) Is amplitude of the electroretinogram reduced in hypermature cataracts compared with immature cataracts?

ag) What is the term used to describe lens-induced uveitis in dogs with cataracts?

ah) Lens-induced uveitis is commonly associated with inflammation in which other ocular tissue?

ai) Lens-induced uveitis is not associated with immature cataracts. Is this true or false?

3. Fluorescein is an important diagnostic aid in clinical ophthalmology, particularly in the diagnosis of ulcers. List four (4) other uses for fluorescein in clinical veterinary ophthalmology.

Continued over page

4. With respect to early onset cone rod dystrophy (CRD) in the standard wire-haired dachshund:

a) Does this condition primarily affect the cones or rods?

a) In the standard wire-haired dachshund, an important clinical feature is used to diagnosis early onset CRD. What is this clinical feature? Choose from the following list:

– prominent iris vessels

– miosis

– mydriasis

– optic nerve hypoplasia.

a) List another canine breed in which cone rod dysplasia CRD is reported as being hereditary.

b) At what age are clinical signs generally first noted in CRD?

5. With respect to canine ehrlichiosis:

a) What is the causative organism for ehrlichiosis?

aj) What is the most common ophthalmic diagnosis?

a) What is the reported percentage of animals presenting with ophthalmic signs as the only complaint? Choose from the following:

– 25%

– 33%

– 50%

– 67%.

ak) List two (2) other ophthalmic clinical signs recognised in cases of ehrlichiosis.

Continued over page

6. Several studies have investigated bacterial flora found in the conjunctival sac of healthy dogs and dogs with ulcerative keratitis. Answer all the following:

a) What instrument is designed to obtain a sample from the dog’s ocular surface for culture and sensitivity?

al) What is the most common bacterial species cultured from eyes with ulcerative keratitis?

am) What bacterial species is most frequently cultured from healthy eyes?

an) In ulcerative keratitis, list two (2) clinical signs associated with deterioration caused by bacterial involvement.

7. Combinations of different medications have been recommended for treating glaucoma in humans. With regards to a fixed combination of dorzolamide–timolol compared with monotherapy with dorzolamide or timolol in dogs:

a) Which drug appears to be the most effective at reducing intraocular pressure in dogs?

ao) Does timolol cause miosis or mydriasis when applied topically to the eye?

ap) What class of antiglaucoma medication is dorzolamide?

aq) Name one (1) other class of antiglaucoma medication.

8. Blunt trauma is a relatively common clinical problem in veterinary ophthalmology. Globe rupture is a common sequel of blunt trauma. Answer both the following:

a) List two (2) clinical signs noted at presentation of this problem.

ar) Where is the most commonly reported site for globe rupture in dogs? Where is the most commonly reported site for globe rupture in horses?

Continued over page

9. With respect to secondary glaucoma in dogs:

a) What percentage of dogs with cataracts develop glaucoma in at least one (1) eye? Choose from the following:

– 10%

– 20%

– 30%

– 40%.

as) Dogs with intracapsular lens extraction (ICCE) are more likely to develop secondary glaucoma. Is this true or false?

at) Define the term ‘neovascular glaucoma’.

au) Which growth factor is most commonly implicated in development of neovascular glaucoma?

10. With respect to primary glaucoma and retinal damage:

a) Where is the earliest damage noted in the ganglion cell in canine glaucoma?

a) The canine retina may regain some visual function 14 days after a marked increase in intraocular pressure resulted in initial vision loss. Is this true or false?

av) The dorsal retina is affected more than the ventral retina in acute elevations of intraocular pressure. Is this true or false?

aw) Apoptosis is programmed cell death and occurs via the intrinsic or extrinsic pathway. Ganglion cell death in glaucoma has features consistent with apoptosis. Is the extrinsic or intrinsic pathway executed by retinal ganglion cells in glaucoma?

11. Tear replacements are an important supplement in cases of keratoconjunctivitis sicca in dogs. Answer both the following:

a) List two (2) bases that are commonly used in tear supplements.

ax) Cyclosporin improves tear production in cases of keratoconjunctivitis sicca. List two (2) potential tear stimulants other than cyclosporine.

Continued over page

12. With respect to optic nerve hypoplasia and aplasia in the dog:

a) From the following list, which breed of dog is most commonly affected:

– border collie

– miniature poodle

– shih tzu

– great Dane.

ay) Is optic nerve aplasia usually a unilateral or bilateral presentation in affected animals?

az) Three retinal structures are missing at a histologic level in optic nerve aplasia. Name one (1).

ba) Most cases of optic nerve hypoplasia are associated with peripheral retinal vessel extension into the vitreous humour. Is this true or false?

13. The alkaloids cyclopamine and jervine are present in Veratum californicum. Answer both the following:

a) Which two (2) congenital abnormalities are reported in offspring of ewes exposed to alkaloids found in Veratum californicum?

bb) On what day of gestation is ingestion associated with these abnormalities, and what is the signalling pathway blocked by cyclopamine?

14. Briefly outline the formation of the lens vesicle. List three (3) potential lens abnormalities associated with abnormal development of the lens. (Do not include defects of mesodermal origin.)

Continued over page

15. Cataract surgery in horses is not without its dramas! Answer all the following:

a) In a recent reported study, what percentage of horses retained their sight four weeks after surgery? Choose from the following values:

– 0%–30%

– 30%–60%

– 60%–90%

– >90%.

bc) List four (4) complications encountered during cataract surgery in the horse.

bd) Aetiology of equine cataracts include congenital/juvenile, traumatic and uveitis-induced cataracts. Which group is reported to have the highest success rate?

16. Answer all the following questions relating to cataracts in rabbits:

a) Name an intralenticular organism that is often suspected of causing cataracts in rabbits.

be) Describe the ocular signs in a clinical case caused by this organism.

bf) What is the treatment of choice of cataracts in rabbits?

bg) What is the suspected mode of transmission of cataracts in rabbits?

17. Neonatal entropion is occasionally seen in foals. List two (2) types of neonatal entropion and their proposed aetiology.

18. Name the two (2) described inherited retinal disorders in the Abyssinian breed of cat. List the age of onset of these two disorders, and their mode of inheritance.

19. Canine eyelid tumours are common in veterinary practice. List eight (8) canine eyelid neoplasms.

20. Briefly define the difference between retinal detachment and senile retinoschisis. List a diagnostic imaging technique that may be useful for differentiating between these retinal diseases. Name another ophthalmic disease in which this imaging technique can help with diagnosis.

Section B over page

Section B — essay question

Answer four (4) of the following five (5) questions only.

1. A cat presents with darkening of the iris in one eye, which the owner noticed over the past four weeks. Discuss your approach in the differentiation of melanosis and melanoma and your recommendations for each, based on clinical signs. What are the treatment options available for melanoma, with reference to any advances in treatment resulting from recent research? If the owner opted for enucleation, include in your discussion the risk of metastatic spread and prognosis based on pathological criteria. Where possible, you should support your answer with specific references to the literature.

2. Lens involvement after penetrating trauma is relatively common in the canine eye. Discuss the various management options and factors that you would use to determine whether to manage a problem medically or surgically. With regards to surgical options, outline your approach, including the surgical technique, instruments and suture materials required. In your discussion, outline the potential complications resulting from such an injury, and the factors that are likely to affect the relative risk of these complications.

3. A cattle farmer calls you to inspect his herd of Simmental cattle. He mentions that about 40% of the cattle have papillomatous conjunctival and corneal lumps in the eyes. What is the most likely diagnosis and what advice would you give? You should include risk factors and aetiology for development of the disease, as well as future prevention. What are the implications for affected cattle with regards to prognosis and behaviour of these masses? Discuss surgical management of these cases with reference to your approach, and the advantages and disadvantages of the treatment chosen.

4. An event horse is referred to you with a focal corneal stromal opacity and history of pain over the past few days. Answer both the following:

a) Discuss your approach, including the diagnostic procedures you would use. List the differential diagnoses in this case. What is the most likely diagnosis? Discuss possible aetiopathogeneses.

bh) Discuss the associated clinical signs you would expect for this condition and the treatment options available (both medical and surgical). What would you advise? Justify your choice.

Continued over page

5. Eyelid surgery is a common procedure for treating entropion in dogs. Answer both the following:

a) Discuss the different types of entropion encountered in dogs and name five (5) dog breeds with breed-related entropion. In your discussion, give reference to the type of entropion and eyelid involvement encountered in each of the mentioned breeds.

bi) Describe two (2) different surgical approaches that may be used to permanently correct entropion in two (2) of the breeds mentioned above, with reference to sutures used and surgical instruments required. Include the reason for your choice in each case, and any postoperative complications that the surgeon should consider.

End of paper

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