Duke - Cornea PDF Past Paper (2021)

9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 1 Chapter Cornea and External Eye 1 Disease Questions 1) Which of the following statements regarding conjunctival anatomy is FALSE?...

9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 1 Chapter Cornea and External Eye 1 Disease Questions 1) Which of the following statements regarding conjunctival anatomy is FALSE? A. The bulbar conjunctiva is continuous with corneal epithelium B. Blood supply is from the anterior ciliary artery C. Goblet cells are found in the conjunctival epithelium D. Accessory lacrimal glands are found in the conjunctival epithelium 2) Which of the following type of discharge is most commonly seen in chronic allergic conjunctivitis? A. Watery B. Mucoid C. Mucopurulent D. Moderately purulent 3) Which of the following statements regarding follicles in conjunctivitis is TRUE? A. They are seen in bacterial conjunctivitis B. They are subepithelial lymphoid germinal centres C. Histologically there are mature cells centrally and immature cells peripherally D. They are almost always abnormal in adults 4) A 20-year-old female presents with an acute unilateral red eye with watery discharge. On a systems review he has some dysuria and urinary frequency. On examination you note conjunctival follicles. Which of the following investigations would NOT be helpful in determining the cause of this? A. McCoy cell culture B. Direct immunofluorescence C. Polymerase chain reaction (PCR) D. Sabouraud agar b4144_Ch-01.indd 1 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 2 3 00 M CQ s F O R T H E D U K E E L D E R O P H T H A L M O LO G Y E X A M 5) A mother has brought in her 6-day-old son, who is complaining of a red right eye with yellow discharge. On inspection, there is hyperpurulent discharge and severe eyelid oedema on the right eye. An ENT examination was normal. Which of the following organisms is most likely responsible for this clinical picture? A. Chlamydia trachomatis B. Herpes simplex virus (HSV) C. Staphylococcus aureus D. Neisseria gonorrhoea 6) A 32-year-old presents with redness and grittiness in her left eye. She is also complaining of a sore throat and a runny nose. On inspection, there is watery discharge and conjunctival hyperaemia. Which of the following is the most likely causative organism? A. HSV B. Adenovirus serovars 3, 4 and 7 C. Coxsackie virus D. Molluscum contagiosum 7) A 54-year-old man presents with grittiness and a painless growth on his left eye. He normally resides in the Middle East. On inspection, there is a triangular ingrowth of conjunctival tissue over the limbus onto the cornea. Which of the following statements regarding this diagnosis is TRUE? A. It typically invades the Bowman layer of the cornea B. It tends to be temporal more often than nasal C. The most common cause is chemical damage to the eye D. Surgery is curative and associated with a low rate of recurrence 8) What is the average central corneal thickness? A. 510 mm B. 530 mm C. 550 mm D. 570 mm b4144_Ch-01.indd 2 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam Co r ne a a nd Ex te rn al Eye D i sea se Q u esti o n s 3 9) Which of the following statements regarding the structure of the cornea is FALSE? A. The epithelium is stratified squamous non-keratinised B. The majority of corneal thickness is comprised of stroma C. The Descemet membrane is secreted by the endothelium D. The Bowman layer contains goblet cells 10) Which of the following organisms is NOT able to penetrate a healthy corneal epithelium? A. Neisseria gonorrhoea B. Neisseria meningitidis C. Corynebacterium diphtheriae D. Staphylococcous aureus 11) Which of the following infections is most likely to cause reduced corneal sensation? A. Herpes keratitis B. Bacterial keratitis C. Fungal keratitis D. Microsporidial keratitis 12) Which of the following statements regarding disciform keratitis is FALSE? A. It may be a hypersensitivity reaction to HSV antigen in the cornea B. Discomfort is milder than with epithelial keratitis C. It typically causes anterior uveitis D. Granulomatous precipitates underlie the oedema 13) A 43-year-old gentleman presents to his GP with an erythematous rash on his face that is causing pain around his eyes. On inspection, he has a well-demarcated vesicular rash on an erythematous base on the right side of his forehead, which does not cross the midline. His right eyelid is oedematous. There are also some lesions involving the side of the nose. Which of the signs in his presentation would confer a high risk of ocular involvement? A. Age B. Eyelid oedema C. Lesion on the side of nose D. Periocular pain b4144_Ch-01.indd 3 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 4 3 00 M CQ s F O R T H E D U K E E L D E R O P H T H A L M O LO G Y E X A M 14) A 12-year-old boy is brought into the clinic with recent severe blurring of his vision. He has hearing aids but is otherwise well. On inspection, you note that he has a saddle-nose deformity and small, widely spaced teeth. Which ocular structure abnormality is likely to explain his visual symptoms? A. Retina B. Conjunctiva C. Corneal stroma D. Lens 15) Which of the following systemic conditions is the most common cause of peripheral ulcerative keratitis? A. Granulomatosis with polyangiitis B. Polyarteritis nodosa C. Systemic lupus erythematosus D. Rheumatoid arthritis 16) Which of the following may NOT cause neurotrophic keratopathy? A. Bell palsy B. HSV keratitis C. Diabetes mellitus D. Stroke 17) Bitot spots, keratomalacia, keratinisation and lustreless cornea are all signs of which disease? A. Sjögren syndrome B. Xerophthalmia C. Filamentary keratopathy D. Keratoconus 18) A 27-year-old presents with a continuous feeling of “something” in his eyes. Occasionally this is accompanied with discomfort to bright lights and redness. On examination there are well- demarcated filament-like lesions stained with rose Bengal seen on the corneal surface. Which of the following is important to enquire about in his history? A. Diet B. Contact lens wear C. Occupation D. Sun exposure b4144_Ch-01.indd 4 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam Co r ne a a nd Ex te rn al Eye D i sea se Q u esti o n s 5 19) Which of the following statements regarding keratoconus is TRUE? A. Eye rubbing has no effect B. LASIK surgery may help C. Most patients often have a family history D. Presentation tends to be with unilateral progressive myopia and astigmatism 20) A 46-year-old female presents with gradual blurring of vision in both eyes, which is noted to be worse in the morning. An examination reveals the appearance of cornea guttata on Descemet membrane. Which of the following is the most likely diagnosis? A. François central cloudy dystrophy B. Fuchs endothelial corneal dystrophy C. Posterior polymorphous corneal dystrophy D. Congenital hereditary endothelial dystrophy 21) A 54-year-old woman presents with worsening vision in both eyes. She mentions that for the past month she has been feeling progressively worse and complains of abdominal pain, constipation, low mood and generalised aches. Which of the following may explain her reduced visual acuity? A. Lipid keratopathy B. Band keratopathy C. Spheroidal degeneration D. Salzmann nodular degeneration 22) A 19-year-old male is seen in an eye clinic. His background includes depression with psychosis, rigidity and tremor, which is under investigation. On a slit lamp examination, you note a brown-yellow zone of dusting in the cornea as well as scleral icterus. Which layer of the cornea are you likely to identify this in? A. Epithelium B. Bowman layer C. Stroma D. Descemet membrane b4144_Ch-01.indd 5 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 6 3 00 M CQ s F O R T H E D U K E E L D E R O P H T H A L M O LO G Y E X A M 23) Which of the following is NOT a contraindication to ocular tissue donation? A. Death from an unknown cause B. Prior high-risk behaviour for HIV and hepatitis C. Corneal refractive surgery D. Prior treated brain cancer 24) Which of the following is a late complication of penetrating keratoplasty? A. Cystoid macular oedema B. Endophthalmitis C. Astigmatism D. Raised intraocular pressure (IOP) 25) A 60-year-old has attended eye casualty complaining of a gradually worsening persistent pain in his right eye, which radiates up to his brows and temple. Analgesia has not helped and the pain has been interfering with his sleep. He has no past medical history of note but has had right trabeculectomy surgery 4 weeks ago. Which of the following are you most likely to find on examination? A. Isolated patches of scleral oedema B. Oedema of the sclera, episclera, conjunctiva and adjacent cornea C. Localised area of necrosis extending outwards D. Diffuse scleral necrosis b4144_Ch-01.indd 6 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 7 Chapter Cornea and External Eye 1 Disease Answers 1) D Conjunctiva is the transparent mucous membrane lining the anterior surface of the eye and the inner surface of the eyelids. It is divided into palpebral, forniceal and bulbar conjunctiva. Blood supply is from the ante- rior ciliary and palpebral arteries, both originating from the ophthalmic artery. The bulbar conjunctiva covers the anterior sclera and is continuous with corneal epithelium. Histologically it is divided into the following: Histology Contents Epithelium Goblet cells Stroma Accessory lacrimal glands of Krause and Wolfring Conjunctiva-associated Lymphocytes and lymphatics Lymphoid Tissue (CALT) 2) B Conjunctival inflammation commonly results in discharge. The char- acter of discharge often indicates the aetiology: Discharge Aetiology Watery Acute viral or acute allergic conjunctivitis Mucoid Chronic allergic conjunctivitis Mucopurulent Chlamydial or acute bacterial conjunctivitis Moderately Purulent Acute bacterial conjunctivitis Severe Purulent Gonococcal conjunctivitis b4144_Ch-01.indd 7 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 8 3 00 M CQ s F O R T H E D U K E E L D E R O P H T H A L M O LO G Y E X A M 3) B Follicles are subepithelial lymphoid germinal centres (central immature lymphocytes and peripheral mature cells), which are seen as slightly elevated lesions on the fornices. The most common causes are viral and chlamydial conjunctivitis. Other causes include hypersensitivity to topical medications. Small follicles are normal in adults when in fornices and at margins of the upper tarsal plate. 4) D This describes a case of acute chlamydial conjunctivitis, which tends to occur in young sexually active patients. In female patients this would present with typical conjunctivitis symptoms and symptoms of chla- mydial urethritis (e.g., dysuria, discharge). Investigations include PCR, Giemsa staining, direct immunofluorescence (to detect free elementary bodies), McCoy cell culture and enzyme immunoassay. Sabouraud agar is used to culture fungal organisms. 5) D Neonatal conjunctivitis typically develops within the first month of life. The following organisms are most commonly implicated: Organism Features Staphylococci · Onset: end of first week · Mildly sticky eye Herpes · Onset: 1–2 weeks simplex virus · May have vesicles and features of encephalitis · Watery discharge Chlamydia · Onset: 1–3 weeks · Disseminated infection is more common than with others (rhinitis, pneumonitis, otitis) · Mucopurulent discharge Neisseria · Onset: first week · Hyperpurulent discharge In this case Neisseria is likely to be the culprit due to its onset and severity. b4144_Ch-01.indd 8 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam Co r ne a a nd Ex te rn a l Eye D i sea se A n swers 9 6) B This is a typical picture of viral conjunctivitis, which commonly follows upper respiratory tract infections. The discharge tends to be watery and conjunctival hyperaemia may be noted on examination. The most common causative organism is adenovirus serovars 3, 4 and 7, which cause pharyngoconjunctival fever. Adenovirus 8, 19 and 37 cause epidemic keratoconjunctivitis, whereby photophobia is a prominent feature. Coxsackie virus causes acute haemorrhagic conjunctivitis, which is typically found in tropical areas, and conjunctival haemorrhage is marked. HSV can cause follicular conjunctivitis with associated skin vesicles. Molluscum contagiosum may cause conjunctivitis by ­autoinoculation following the shedding of the virus from skin lesions. 7) A The lesion being described is a pterygium. Pinguecula and pterygia tend to be more nasal than temporal. The most common cause is ultraviolet (UV) exposure. Unlike pinguecula, a pterygium encroaches on the cornea and invades the Bowman layer. Often, it is painless — patients may complain of dry eyes but it may occasionally become acutely inflamed. Management is often conservative (as for pinguecula) — patients are advised to reduce exposure to UV light and to use regular eye lubricants. Surgical excision is associated with a high recurrence rate. 8) C The average thickness of the central cornea is between 540 and 560 mm. Generally, a value of below 535 mm is considered thin. Above 565 mm, it is considered thick. 9) D The layers of the cornea from superficial to deep are: Epithelium → Bowman layer → Stroma → Descemet membrane → Endothelium The epithelium is stratified squamous and non-keratinised, compro- mising of a single layer of columnar basal cells. The Bowman layer is acellular and is formed from collagen fibres. The stroma (substantia propria) makes up the majority of corneal thickness. The Descemet mem- brane is a basement membrane, which is secreted by the endothelium. b4144_Ch-01.indd 9 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 1 0 3 00 M CQ s F O R T H E D U K E E L D E R O P H T H A L M O LO G Y E X A M 10) D Bacterial keratitis occurs when ocular defences are compromised (e.g., trauma, contact lens wear and dry eyes). Common pathogens are Streptococcus spp., Staphylococcus aureus and Pseudomonas aerugi- nosa. Certain bacteria are able to penetrate healthy corneal epithelium such as Neisseria gonorrhoeae, Neisseria meningitidis, Corynebacterium diphtheriae and Haemophilus influenzae. 11) A Reduced corneal sensation is a feature of both bacterial and HSV kera- titis. In bacterial keratitis, reduced corneal sensation would suggest associated neurotrophic keratopathy. Reduced sensation is more common with HSV. It is rarely associated with microsporidial and fungal keratitis. 12) C Epithelial keratitis, disciform keratitis and necrotising stromal keratitis may all result from HSV infection. Disciform keratitis is either a ­hypersensitivity reaction to HSV in the cornea or a result of active ­infection of the endothelium layer. Gradual blurring of vision, discom- fort and redness are common symptoms (discomfort is milder than epithelial disease). Necrotising stromal keratitis causes anterior uveitis with keratic precipitates underlying the area of active stromal infiltration. 13) C This is a case of herpes zoster ophthalmicus whereby shingles affects the dermatome supplied by the ophthalmic division of the trigeminal nerve. Risk factors for ocular involvement are: · Age: the signs and symptoms are more severe in the elderly and tend to present most frequently in the 6th and 7th decade · Immunocompromised (i.e., AIDS) · Hutchinson sign: this is when there is involvement of the skin on the nose (supplied by the external nasal nerve, a branch of the nasociliary nerve) 14) C This is a case of congenital syphilis. Systemic signs tend to be sensori- neural deafness, a saddle-nose deformity, Hutchinson teeth (small, b4144_Ch-01.indd 10 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam Co r ne a a nd Ex te rn a l Eye D i sea se A n swers 11 widely spaced teeth) and sabre tibiae (anterior bowing of the tibia). Ocular features include: anterior uveitis, interstitial keratitis, cataract, optic atrophy, “salt and pepper” retinopathy and the Argyll Robertson pupil. The gradual blurring of vision presenting between the ages of 5–25 years is typical of interstitial keratitis, which involves the corneal stroma. 15) D Peripheral ulcerative keratitis refers to thinning preferentially affecting the peripheral cornea. Systemic autoimmune diseases result in the upregulation of collagenases. The most common systemic disease associated with this is rheumatoid arthritis. Others include granulomatosis with polyangiitis, polyarteritis nodosa and systemic lupus erythematosus. 16) A Neurotrophic keratopathy is caused by the failure of re-epithelialisation resulting from corneal anaesthesia. The causes include stroke, tumour, peripheral neuropathy (e.g., from diabetes mellitius) and herpes (simplex and zoster) infections. Bell palsy causes exposure keratopathy. 17) B Xerophthalmia describes the ocular manifestations that occur in response to vitamin A deficiency. Patients will complain of night blindness, discomfort and loss of vision. Dryness of the conjunctiva manifests with Bitot spots (patches of foamy keratinised epithelium). Dryness of the cornea manifests with lustreless appearance, keratini- sation and keratomalacia in severe cases. The WHO’s grading of xerophthalmia is: XN Night Blindness X1 Conjunctival xerosis with Bitot spots X2 Corneal xerosis X3 Corneal ulceration XS Corneal scar XF Xerophthalmic fundus b4144_Ch-01.indd 11 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 1 2 3 00 M CQ s F O R T H E D U K E E L D E R O P H T H A L M O LO G Y E X A M 18) B Filamentary keratopathy is a condition whereby mucus and cellular debris become trapped in a loose area of the corneal epithelium. Patients typically complain of discomfort with a foreign body sensation and occasional photophobia. Filaments can be seen that stain with rose Bengal. Management is aimed at treating the underlying cause. Causes include:  Excessive contact lens wear  Neurotrophic keratopathy  Keratoconjunctivitis sicca  Surgery: corneal graft, refractive surgery and cataract surgery 19) D Keratoconus is a disorder where there is progressive thinning of the central corneal stroma with apical protrusion and irregular astigmatism. Most patients do not have a family history. It may be associated with systemic conditions such as Ehlers-Danlos syndrome, Marfan syndrome, osteogenesis imperfecta and Down syndrome. Presentation tends to be with unilateral progressive myopia and astigmatism. LASIK surgery is contraindicated. Patients are advised to avoid eye rubbing, which may exacerbate corneal thinning. 20) B Fuchs endothelial corneal dystrophy results in a gradual blurring of vision in both eyes, more commonly in females and manifests in middle age. It results in bilateral accelerated endothelial cell loss. Cornea guttata are often present in the early stage; these represent irregular warts excreted by abnormal endothelial cells on Descemet membrane. 21) B The symptoms this woman exhibits are those of hypercalcaemia (“stones, bones, abdominal moans, and psychic groans”). Ocular mani- festations of hypercalcaemia include band keratopathy, which consists of calcium deposition in the epithelial layer, Bowman layer and anterior stroma. b4144_Ch-01.indd 12 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam Co r ne a a nd Ex te rn a l Eye D i sea se A n swers 13 22) D This young male has Wilson disease, which tends to present with liver disease, basal ganglia dysfunction and psychiatric disturbances as a result of excess deposition of copper. On a slit lamp examination, the Kayser-Fleischer ring may be present, which consists of a brown-yellow zone of copper dusting in the Descemet membrane. 23) D Some of the contraindications to ocular tissue donation include: · Death from an unknown cause · Systemic infections such as HIV, viral hepatitis, syphilis, congenital rubella and tuberculosis · Prior high-risk behaviour for HIV and hepatitis · CNS disorders: CJD, dementias, Parkinson disease, multiple sclerosis and motor neurone disease · Receipt of a transplanted organ · Haematological malignancy · Corneal refractive surgery · Ocular tumours 24) C Penetrating keratoplasty refers to a surgical procedure that replaces a diseased cornea with a donated, full-thickness corneal graft. Postoperative complications can be subdivided into early and late complications: Early Complications Late Complications · Infection: microbial keratitis, · Astigmatism endophthalmitis · Glaucoma · Rejection · Late wound · Wound leak, graft rupture dehiscence · Raised IOP · Rejection · Cystoid macular oedema · Fixed dilated pupil (Urrets-Zavalia syndrome) b4144_Ch-01.indd 13 19-04-2021 11.31.45 AM  9”x6” b4144   300 MCQs for the Duke Elder Ophthalmology Exam 1 4 3 00 M CQ s F O R T H E D U K E E L D E R O P H T H A L M O LO G Y E X A M 25) C This is an anterior necrotising scleritis, which tends to present with gradually worsening pain that radiates to the brow, temple or jaw. It responds poorly to analgesia. There are three main subtypes, according to cause, as outlined in the table below. Subtype of Anterior Scleritis Cause and Signs Vaso-occlusive · Caused by rheumatoid arthritis · Results in isolated patches of scleral oedema Granulomatous · Caused by granulomatosis with polyangiitis and polyarteritis nodosa · Results in diffuse oedema of the sclera, episclera, conjunctiva and adjacent cornea Surgical · Usually within 3 weeks of proce- dure (any type) · Results in a localised necrotising process extending outwards In this case, the likely cause is the recent trabeculectomy surgery. b4144_Ch-01.indd 14 19-04-2021 11.31.46 AM