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Iraqi Board Ophthalmology study materials
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Iraqi Board Ophthalmology practice questions

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Question 1Basic and Clinical Optics, Refraction and Contact Lenses

A reduced eye model has a single refracting surface with a power of 60 D. What is its principal focal length in air?

  1. 24.00 mm
  2. 16.67 mm Correct answer.
  3. 22.22 mm
  4. 60.00 mm

Explanation

Focal length in metres equals the reciprocal of surface power, so 1/60 D = 0.01667 m, which is 16.67 mm. This is the secondary focal length measured in air for the reduced eye model.

Question 2Basic and Clinical Optics, Refraction and Contact Lenses

Which statement correctly describes the optics of a pinhole aperture placed before a myopic eye?

  1. It eliminates chromatic aberration but worsens spherical aberration
  2. It reduces blur circles and improves acuity by restricting the effective bundle of rays Correct answer.
  3. It corrects the refractive error by changing the eye's total power
  4. It increases retinal image size while reducing depth of focus

Explanation

A pinhole removes the peripheral rays so that each retinal point receives a narrower cone of light, shrinking the blur circle regardless of the refractive error. It does not alter the eye's power, and it actually increases depth of focus.

Question 3Basic and Clinical Optics, Refraction and Contact Lenses

A spectacle lens of power +10.00 D is worn at a vertex distance of 12 mm from the cornea. What power must the equivalent contact lens have?

  1. +11.36 D Correct answer.
  2. +10.00 D
  3. +12.50 D
  4. +8.93 D

Explanation

The effective power formula is Fc = Fs / (1 - d·Fs), with d in metres. Substituting gives 10 / (1 - 0.012×10) = 10 / 0.88 = +11.36 D, so a higher plus power is needed at the cornea.

Question 4Basic and Clinical Optics, Refraction and Contact Lenses

In a Jackson cross-cylinder refraction, the patient reports that both flip positions are equally blurry. What is the most appropriate next step?

  1. Rotate the axis by 45 degrees and repeat the test
  2. Reduce the cylinder power and recheck the axis
  3. Increase the sphere by +0.50 D and repeat
  4. Accept the current axis as correct and proceed to check cylinder power Correct answer.

Explanation

Equal blur in both positions of the cross-cylinder indicates the axis is already correctly aligned, so the axis check is complete. The examiner then proceeds to refine the cylinder power using the same cross-cylinder.

Question 5Basic and Clinical Optics, Refraction and Contact Lenses

Which keratometric finding is most consistent with a diagnosis of keratoconus?

  1. Inferior steepening with distorted mires and asymmetric astigmatism Correct answer.
  2. Superior flattening with circular mires
  3. Symmetric bow-tie astigmatism with regular mires
  4. With-the-rule astigmatism with a stable axis over time

Explanation

Keratoconus characteristically produces inferior corneal steepening, irregular astigmatism, and distorted or broken keratometry mires. Symmetric regular patterns and stable axes argue against ectasia.

Question 6Basic and Clinical Optics, Refraction and Contact Lenses

A soft contact lens has a back vertex power of -3.00 D, a base curve of 8.40 mm, and a centre thickness of 0.10 mm. Which parameter is defined as the base curve in this specification?

  1. The radius of curvature of the anterior lens surface
  2. The radius of curvature of the posterior lens surface Correct answer.
  3. The diameter of the optical zone
  4. The sagittal depth of the lens periphery

Explanation

In contact lens terminology the base curve is the radius of curvature of the back (posterior) surface, which governs the fit against the cornea. The anterior surface curvature is described as the front optic radius.

Question 7Basic and Clinical Optics, Refraction and Contact Lenses

A rigid gas-permeable lens shows excessive apical bearing with pooling of fluorescein in the mid-periphery. Which lens modification is most appropriate?

  1. Flatten the base curve
  2. Increase the overall diameter without changing curvature
  3. Reduce the optic zone diameter
  4. Steepen the base curve Correct answer.

Explanation

Apical bearing indicates the lens is too flat relative to the cornea, so steepening the base curve (shorter radius) increases sagittal depth and relieves the central touch. Pooling mid-peripherally is consistent with this steep-flat mismatch.

Question 8Basic and Clinical Optics, Refraction and Contact Lenses

What is the primary optical advantage of an aspheric spectacle lens design?

  1. It eliminates oblique astigmatism at all angles of gaze
  2. It increases the field of view beyond the frame aperture
  3. It reduces peripheral distortion and lens thickness while maintaining central optics Correct answer.
  4. It removes the need for a distance prescription

Explanation

Aspheric surfaces progressively flatten toward the periphery, reducing marginal thickness and off-axis aberrations such as oblique astigmatism and distortion. Central optical performance is preserved while cosmesis and weight improve.

Question 9Basic and Clinical Optics, Refraction and Contact Lenses

A patient's retinoscopy at a working distance of 50 cm shows a neutral reflex with a +2.00 D lens in place. What is the net refractive error?

  1. Plano Correct answer.
  2. +4.00 D
  3. +2.00 D
  4. -2.00 D

Explanation

At a 50 cm working distance the examiner must subtract 2.00 D of working distance artifact from the neutralizing lens. Adding +2.00 D and subtracting 2.00 D yields plano.

Question 10Basic and Clinical Optics, Refraction and Contact Lenses

Which phenomenon explains why a patient with a high hyperopic prescription notices object size changes when switching from spectacles to contact lenses?

  1. Aniseikonia from unequal retinal image sizes
  2. Spectacle magnification changes with vertex distance and lens power Correct answer.
  3. Prism induced by lens decentration
  4. Accommodative convergence excess

Explanation

Spectacle magnification depends on lens power and vertex distance, so moving a high plus correction onto the cornea reduces image magnification. This produces a perceived change in object size without true aniseikonia.

Question 11Basic and Clinical Optics, Refraction and Contact Lenses

Which statement about the Stiles-Crawford effect is correct?

  1. It describes the change in refractive error with accommodation
  2. The effect is strongest for rod-mediated night vision
  3. Rays entering through the pupil centre are perceived as brighter than marginal rays Correct answer.
  4. Marginal rays are perceived as brighter because of oblique incidence on cones

Explanation

The Stiles-Crawford effect is the directional sensitivity of cones, whereby light entering near the pupil centre appears brighter than light entering at the margin. It is a cone-mediated phenomenon and is minimal in rod vision.

Question 12Basic and Clinical Optics, Refraction and Contact Lenses

A 10-year-old achieves 6/6 with a +1.00 D sphere and reports no symptoms. Which interpretation is most appropriate?

  1. This indicates pseudomyopia requiring cycloplegic refraction
  2. This is likely physiological hyperopia that may not require correction Correct answer.
  3. This represents significant latent hyperopia requiring full correction
  4. This suggests accommodative insufficiency needing orthoptic exercises

Explanation

Low hyperopia in a child with good acuity and no symptoms is common and usually requires no correction because accommodation compensates. Correction is reserved for symptoms, strabismus, or high refractive error.

Question 13Basic and Clinical Optics, Refraction and Contact Lenses

Which formula correctly expresses the relationship between vergence and distance for a wavefront in air?

  1. Vergence equals the reciprocal of the distance in metres Correct answer.
  2. Vergence equals distance divided by refractive index
  3. Vergence equals the square of the focal length
  4. Vergence equals distance multiplied by refractive index

Explanation

Vergence in dioptres is the reciprocal of the distance from the wavefront to the reference point, expressed in metres. A converging wavefront at 0.5 m therefore has +2.00 D of vergence.

Question 14Basic and Clinical Optics, Refraction and Contact Lenses

A patient wearing a +12.00 D spectacle lens has the optical centre displaced 4 mm below the visual axis. What prismatic effect is induced at the visual axis?

  1. 4.8 prism dioptres base down
  2. 4.8 prism dioptres base up Correct answer.
  3. 0.48 prism dioptres base up
  4. 48 prism dioptres base down

Explanation

Prentice's rule gives prism in dioptres as decentration in centimetres multiplied by lens power, so 0.4 cm × 12 D = 4.8 prism dioptres. A plus lens decentred downward induces base-up prism at the line of sight.

Question 15Basic and Clinical Optics, Refraction and Contact Lenses

Which design feature of a multifocal contact lens most closely mimics the optical principle of a diffractive bifocal intraocular lens?

  1. A single progressive power gradient across the optic
  2. A monovision fit with unequal distance powers
  3. Alternating concentric zones of differing power Correct answer.
  4. A translating lens with a flat inferior segment

Explanation

Diffractive multifocal designs use concentric zones that direct light to near and distance foci simultaneously, analogous to alternating zones in a contact lens. Progressive and translating designs rely on different optical mechanisms.

Question 16Basic and Clinical Optics, Refraction and Contact Lenses

In a schematic eye with a total power of 60 D and an axial length of 24 mm, what is the refractive state in air?

  1. 1.00 D of axial hyperopia
  2. Emmetropic because axial length matches focal length
  3. 2.00 D of axial myopia Correct answer.
  4. 4.00 D of axial myopia

Explanation

A 60 D eye has a focal length of 16.67 mm in air, but the schematic eye's ocular refraction is calculated using the reduced eye convention where 1 mm of axial length corresponds to about 3 D. An axial length of 24 mm exceeds the emmetropic value, producing axial myopia of roughly 2 D in this simplified model.

Question 17Cornea, External Disease and Anterior Segment

A 24-year-old man presents with a painful red left eye and a dendritic corneal epithelial lesion that stains with fluorescein. He wears contact lenses. Which antiviral agent is the standard first-line topical treatment for this epithelial keratitis?

  1. Topical trifluridine 1% Correct answer.
  2. Oral famciclovir
  3. Topical ganciclovir gel 0.15%
  4. Topical acyclovir 3% ointment

Explanation

Epithelial herpes simplex keratitis classically shows a branching dendritic ulcer with terminal bulbs that stains with fluorescein and rose bengal. Topical trifluridine 1% is a standard first-line topical antiviral in many centers, with topical ganciclovir gel as an accepted alternative. Oral antivirals are used more for stromal disease or prophylaxis, not as first-line therapy for a simple epithelial dendrite.

Question 18Cornea, External Disease and Anterior Segment

Which clinical sign best distinguishes a corneal abrasion from a corneal ulcer on slit-lamp examination?

  1. Presence of a fluorescein-staining epithelial defect with underlying stromal infiltrate Correct answer.
  2. Presence of photophobia
  3. Presence of conjunctival injection
  4. Presence of a positive Seidel test

Explanation

A corneal ulcer is defined by an epithelial defect accompanied by an underlying stromal infiltrate, which implies infection or active inflammation. A simple abrasion shows epithelial loss with fluorescein staining but no stromal infiltrate. Conjunctival injection and photophobia occur in both conditions and therefore do not discriminate between them.

Question 19Cornea, External Disease and Anterior Segment

A patient with severe dry eye has a Schirmer I test result of 3 mm after 5 minutes without anesthesia. What does this result most directly indicate?

  1. Meibomian gland dysfunction alone
  2. Normal reflex tearing
  3. Aqueous-deficient dry eye Correct answer.
  4. Increased corneal sensitivity

Explanation

The Schirmer I test without anesthesia measures total tear secretion, including reflex tearing. A value of 5 mm or less after 5 minutes is generally considered abnormal and suggests aqueous-deficient dry eye. Meibomian gland dysfunction primarily affects the lipid layer and would not by itself produce a markedly low Schirmer I result.

Question 20Cornea, External Disease and Anterior Segment

Which of the following is the most common organism causing bacterial keratitis in contact lens wearers?

  1. Streptococcus pneumoniae
  2. Mycobacterium fortuitum
  3. Moraxella catarrhalis
  4. Pseudomonas aeruginosa Correct answer.

Explanation

Pseudomonas aeruginosa is the classic and most common cause of contact lens-associated bacterial keratitis, often presenting with a rapidly progressive ulcer and ring infiltrate. Streptococcus pneumoniae and Moraxella are more typical of ulceration after ocular surface compromise or trauma. Atypical mycobacteria are rarer and often linked to specific exposures such as LASIK or contaminated water.

Question 21Cornea, External Disease and Anterior Segment

A 65-year-old man reports gradually decreasing vision and glare. Slit-lamp examination reveals a dense central corneal opacity with a grayish-brown color and a distinct border. Which condition is most consistent with these findings?

  1. Band keratopathy
  2. Fuchs endothelial dystrophy Correct answer.
  3. Corneal degeneration
  4. Corneal arcus

Explanation

Fuchs endothelial dystrophy produces central corneal edema with decreased vision and glare, often with a beaten-metal appearance of the endothelium and guttae. Corneal arcus is a peripheral lipid ring that spares the central cornea and does not typically reduce vision. Band keratopathy shows a chalky interpalpebral band, and corneal degenerations are usually peripheral.

Question 22Cornea, External Disease and Anterior Segment

Which finding on slit-lamp examination is most characteristic of keratoconus?

  1. Central corneal ectasia with inferior steepening and Fleischer ring Correct answer.
  2. Peripheral corneal neovascularization
  3. Circumferential corneal thinning
  4. Diffuse punctate epithelial erosions

Explanation

Keratoconus produces central or paracentral corneal ectasia with inferior steepening on topography, and a Fleischer ring of iron deposition at the cone base. Circumferential thinning suggests a different ectatic or degenerative process. Punctate erosions and peripheral neovascularization are nonspecific and occur in many corneal disorders.

Question 23Cornea, External Disease and Anterior Segment

A patient has a corneal epithelial defect after trauma. Which topical medication should be avoided during healing because of its potential to delay epithelialization?

  1. Preservative-free artificial tears
  2. Topical moxifloxacin
  3. Topical sodium hyaluronate
  4. Topical prednisolone acetate Correct answer.

Explanation

Topical corticosteroids suppress inflammation but can retard corneal epithelial healing and increase the risk of infection and melting when used in the presence of an epithelial defect. Preservative-free lubricants and sodium hyaluronate support epithelial recovery. Fluoroquinolones are used to prevent or treat bacterial infection and do not delay healing in the same way.

Question 24Cornea, External Disease and Anterior Segment

A 30-year-old woman has bilateral recurrent corneal erosions every morning. She recalls a foreign body injury to one eye several months ago. What is the most likely diagnosis?

  1. Herpes zoster ophthalmicus
  2. Recurrent corneal erosion syndrome after trauma Correct answer.
  3. Epithelial basement membrane dystrophy
  4. Acanthamoeba keratitis

Explanation

Recurrent corneal erosions after a prior corneal abrasion result from defective hemidesmosomal adhesion of the epithelium to the basement membrane. Patients typically report sharp pain on waking as the eyelid strips the loosely adherent epithelium. Epithelial basement membrane dystrophy can cause similar symptoms but is bilateral and not related to trauma.

Question 25Cornea, External Disease and Anterior Segment

A patient with long-standing rheumatoid arthritis develops a corneal ulcer with severe thinning and perforation risk. Which underlying mechanism best explains this presentation?

  1. Neurotrophic keratopathy from trigeminal damage
  2. Infectious keratitis from Staphylococcus aureus
  3. Exposure keratopathy from proptosis
  4. Peripheral ulcerative keratitis from immune complex deposition Correct answer.

Explanation

Peripheral ulcerative keratitis in rheumatoid arthritis results from immune complex deposition and complement activation at the limbus, leading to stromal melting and perforation. It is a sterile inflammatory process rather than a primary infection. Neurotrophic and exposure keratopathy have different clinical features and are not the primary mechanism in rheumatoid-associated melting.

Question 26Cornea, External Disease and Anterior Segment

Which of the following best describes the appropriate initial management of a chemical eye injury with an alkaline agent?

  1. Removal of all conjunctival tissue
  2. Application of topical corticosteroid before irrigation
  3. Immediate copious irrigation with saline or balanced salt solution Correct answer.
  4. Immediate penetrating keratoplasty

Explanation

Alkali injuries penetrate deeply and cause progressive tissue damage, so immediate and copious irrigation is the priority to dilute and remove the agent. Corticosteroids may be used later to control inflammation but should not delay irrigation. Surgical debridement of conjunctiva and emergency keratoplasty are not first-line measures.

Question 27Cornea, External Disease and Anterior Segment

A 45-year-old contact lens wearer presents with severe pain, a ring-shaped corneal infiltrate, and poor response to antibacterial therapy. What is the most likely diagnosis?

  1. Fungal keratitis
  2. Herpes simplex keratitis
  3. Acanthamoeba keratitis Correct answer.
  4. Marginal keratitis

Explanation

Acanthamoeba keratitis classically occurs in contact lens wearers, causes pain out of proportion to clinical signs, and may produce ring infiltrates and radial keratoneuritis. It often fails to respond to antibacterial treatment. Herpes simplex causes dendritic lesions, fungal keratitis usually follows plant trauma, and marginal keratitis is an immune response at the limbus.

Question 28Cornea, External Disease and Anterior Segment

Which corneal dystrophy is characterized by bilateral, symmetric, granular deposits in the anterior stroma that stain with Masson trichrome?

  1. Lattice corneal dystrophy
  2. Fuchs endothelial dystrophy
  3. Macular corneal dystrophy
  4. Granular corneal dystrophy Correct answer.

Explanation

Granular corneal dystrophy shows discrete, sharply demarcated hyaline deposits in the anterior stroma that stain with Masson trichrome. Macular dystrophy has diffuse stromal opacification with acid mucopolysaccharide deposits that stain with alcian blue. Lattice dystrophy shows branching amyloid lines, and Fuchs dystrophy affects the endothelium.

Question 29Cornea, External Disease and Anterior Segment

A patient with a penetrating corneal injury has a positive Seidel test. What does this finding indicate?

  1. A full-thickness corneal wound with aqueous leakage Correct answer.
  2. A superficial epithelial abrasion
  3. An intact corneal epithelium
  4. A retained intraocular foreign body

Explanation

A positive Seidel test occurs when fluorescein dye applied to the cornea is diluted by aqueous humor leaking through a full-thickness wound. It confirms an open globe and requires urgent surgical management. Superficial abrasions and intact epithelium do not produce aqueous leakage.

Question 30Cornea, External Disease and Anterior Segment

Which of the following is the most appropriate treatment for a patient with severe neurotrophic keratopathy and a persistent epithelial defect?

  1. Topical corticosteroid alone
  2. Topical anesthetic drops
  3. Preservative-free lubricants and autologous serum Correct answer.
  4. Bandage contact lens without lubrication

Explanation

Neurotrophic keratopathy results from impaired corneal sensation and healing, so management focuses on protecting the surface and promoting epithelialization. Preservative-free lubricants and autologous serum provide growth factors and support healing. Topical anesthetics are toxic to the epithelium and should be avoided.

Question 31Cornea, External Disease and Anterior Segment

A 70-year-old patient with a history of herpes zoster ophthalmicus develops a persistent corneal epithelial defect with decreased corneal sensation. Which mechanism best explains this finding?

  1. Limbal stem cell deficiency from chronic inflammation
  2. Corneal edema from endothelial failure
  3. Immune ring infiltration
  4. Neurotrophic keratopathy from trigeminal nerve damage Correct answer.

Explanation

Herpes zoster ophthalmicus can damage the ophthalmic division of the trigeminal nerve, reducing corneal sensation and producing neurotrophic keratopathy with persistent epithelial defects. Limbal stem cell deficiency and endothelial failure have different clinical patterns. Immune ring infiltration is a sign of active inflammation rather than a cause of persistent epithelial breakdown.

Question 32Cornea, External Disease and Anterior Segment

A 55-year-old woman has bilateral corneal edema, central guttae on specular microscopy, and reduced vision. Which surgical approach is most appropriate when cataract surgery is also required?

  1. Phacoemulsification alone
  2. Radial keratotomy
  3. Combined phacoemulsification with endothelial keratoplasty Correct answer.
  4. Penetrating keratoplasty alone

Explanation

Fuchs endothelial dystrophy with visually significant edema and cataract is best managed by combining cataract extraction with endothelial keratoplasty, which replaces the diseased endothelium while correcting the lens opacity. Phacoemulsification alone risks worsening corneal edema. Penetrating keratoplasty is reserved for more extensive stromal scarring, and radial keratotomy is not a treatment for endothelial disease.

Question 33Cornea, External Disease and Anterior Segment

A patient presents with a corneal ulcer and hypopyon that worsened despite topical antibiotics. Gram stain shows gram-negative rods, and the patient reports contact lens wear with tap water rinsing. Which organism should be suspected?

  1. Staphylococcus epidermidis
  2. Corynebacterium diphtheriae
  3. Propionibacterium acnes
  4. Pseudomonas aeruginosa Correct answer.

Explanation

Pseudomonas aeruginosa is a gram-negative rod associated with contact lens wear, contaminated water, and rapidly progressive keratitis with hypopyon. Staphylococcus epidermidis and Propionibacterium acnes are gram-positive organisms. Corynebacterium diphtheriae is not a typical cause of contact lens-associated keratitis.

Question 34Cornea, External Disease and Anterior Segment

A patient with a history of LASIK presents with decreased vision and interface fluid on slit-lamp examination. Which measurement is most important in confirming the diagnosis?

  1. Anterior chamber depth by ultrasound biomicroscopy
  2. Intraocular pressure by Goldmann applanation tonometry
  3. Central corneal thickness by ultrasound pachymetry Correct answer.
  4. Corneal topography

Explanation

Interface fluid syndrome after LASIK can falsely lower intraocular pressure readings by Goldmann applanation because the fluid pocket absorbs pressure. Measuring central corneal thickness by ultrasound pachymetry helps confirm the diagnosis and assess corneal edema. Topography and anterior chamber depth do not directly confirm interface fluid.

Question 35Cornea, External Disease and Anterior Segment

A patient with a corneal transplant develops a rejection episode with an endothelial rejection line. Which treatment is most appropriate?

  1. Observation alone
  2. Immediate repeat penetrating keratoplasty
  3. Topical antibiotics alone
  4. Intensive topical and systemic corticosteroids Correct answer.

Explanation

Endothelial rejection after corneal transplantation is treated promptly with intensive topical corticosteroids and often systemic steroids to suppress the immune response and preserve the graft. Observation risks irreversible endothelial loss. Antibiotics alone do not address the immune mechanism, and repeat keratoplasty is reserved for grafts that fail despite treatment.

Question 36Cornea, External Disease and Anterior Segment

A patient with chronic blepharitis develops recurrent corneal epithelial breakdown with a whorl-like pattern and reduced corneal sensation. Which diagnosis should be considered?

  1. Corneal ectasia
  2. Limbal stem cell deficiency Correct answer.
  3. Herpes simplex stromal keratitis
  4. Recurrent corneal erosion

Explanation

Limbal stem cell deficiency produces a whorl-like epithelial pattern with breakdown, vascularization, and sometimes reduced sensation, often in the setting of chronic ocular surface inflammation. Recurrent erosion follows trauma, herpes stromal keratitis produces scarring and vascularization, and ectasia produces thinning and steepening rather than a whorl pattern.

Question 37Glaucoma

A 62-year-old man with open-angle glaucoma has a cup-to-disc ratio of 0.9 with a thin neuroretinal rim. Which visual field defect is most consistent with this level of glaucomatous damage?

  1. Bitemporal hemianopia
  2. Central scotoma
  3. Homonymous hemianopia
  4. Superior arcuate scotoma Correct answer.

Explanation

Glaucomatous optic neuropathy produces nerve-fibre-bundle visual field defects that respect the horizontal meridian, the classic being an arcuate (Bjerrum) scotoma starting near the blind spot. Severe cupping of the inferior pole damages superior fibres, giving a superior arcuate defect. Chiasmal and retrochiasmal patterns do not respect the horizontal midline.

Question 38Glaucoma

Which measurement best defines a normal open anterior chamber angle on gonioscopy?

  1. Peripheral iris apposed to the trabecular meshwork
  2. Schwalbe line visible but trabecular meshwork hidden
  3. Iris root inserted anterior to the scleral spur
  4. Ciliary body band visible with posterior trabecular meshwork Correct answer.

Explanation

A wide-open angle shows the scleral spur, posterior and anterior trabecular meshwork, Schwalbe line and often the ciliary body band. Visibility of the posterior trabecular meshwork without manipulation indicates a structure that is open and not occludable. The other descriptions indicate narrow or closed configurations.

Question 39Glaucoma

A 70-year-old woman presents with a painful red eye, hazy cornea, mid-dilated fixed pupil and intraocular pressure of 58 mmHg. Which is the most appropriate immediate management?

  1. Topical antibiotic and review in one week
  2. Pilocarpine alone as definitive therapy
  3. Lower the pressure medically and perform laser peripheral iridotomy Correct answer.
  4. Topical steroid alone

Explanation

The picture is acute angle-closure glaucoma, an emergency requiring immediate IOP lowering with topical and systemic agents plus definitive relief of pupillary block by laser peripheral iridotomy. Pilocarpine is adjunctive but is less effective while the iris sphincter is ischaemic. Delay risks permanent optic nerve and corneal damage.

Question 40Glaucoma

Which optic disc feature is most characteristic of glaucomatous rather than physiological cupping?

  1. Cup-to-disc ratio of 0.3 in both eyes
  2. Pallor of the disc with a normal cup
  3. Focal thinning of the inferotemporal neuroretinal rim with disc haemorrhage Correct answer.
  4. Central cup with intact pink neuroretinal rim all round

Explanation

Glaucomatous cupping is characterised by focal or diffuse neuroretinal rim loss, classically inferotemporal, with associated disc haemorrhage, bayonet vessels and laminar dots. A large symmetrical cup with healthy rim can be physiological. Disc pallor with a normal cup suggests non-glaucomatous optic neuropathy.

Question 41Glaucoma

Which class of topical medication lowers intraocular pressure by increasing uveoscleral outflow?

  1. Carbonic anhydrase inhibitors
  2. Beta-adrenoceptor antagonists
  3. Prostaglandin analogues Correct answer.
  4. Alpha-2 agonists

Explanation

Prostaglandin analogues such as latanoprost increase uveoscleral outflow through remodelling of the ciliary muscle extracellular matrix and are first-line for open-angle glaucoma. Beta-blockers and carbonic anhydrase inhibitors reduce aqueous production, and alpha-2 agonists do both.

Question 42Glaucoma

A patient using topical timolol asks about side effects. Which systemic effect should be specifically discussed?

  1. Bradycardia and bronchospasm Correct answer.
  2. Hyperthyroidism
  3. Hyperglycaemia
  4. Renal calculi

Explanation

Timolol is a non-selective beta-blocker and is absorbed systemically through the nasolacrimal mucosa, causing bradycardia, heart block, hypotension and bronchospasm. It should be avoided in asthma and second-degree or greater heart block. Punctal occlusion reduces this systemic absorption.

Question 43Glaucoma

Which finding on gonioscopy is diagnostic of pigment dispersion syndrome?

  1. Peripheral anterior synechiae
  2. Dense homogeneous trabecular pigmentation with a Sampaolesi line Correct answer.
  3. Neovascularisation of the angle
  4. Blood in Schlemm canal

Explanation

Pigment dispersion syndrome shows heavy, uniform pigmentation of the trabecular meshwork with pigment anterior to Schwalbe line (Sampaolesi line), often with mid-peripheral iris transillumination defects. The pigment is released from iris pigment epithelium rubbing against zonules. Neovascularisation and synechiae indicate other mechanisms.

Question 44Glaucoma

A 55-year-old hypermetropic woman has bilateral narrow angles on gonioscopy and no symptoms. What is the most appropriate management?

  1. Long-term pilocarpine
  2. Observation only with annual review
  3. Prophylactic laser peripheral iridotomy after discussion of risks Correct answer.
  4. Bilateral trabeculectomy

Explanation

Prophylactic laser peripheral iridotomy is considered for eyes with occludable angles at high risk of closure, particularly hypermetropic eyes with a shallow anterior chamber. It reduces the risk of acute angle-closure attack. Trabeculectomy is far too invasive for prophylaxis and pilocarpine is not a preventive strategy.

Question 45Glaucoma

Which factor most strongly predicts progression of visual field loss in primary open-angle glaucoma?

  1. Iris colour
  2. Patient height
  3. Elevated intraocular pressure at baseline and during follow-up Correct answer.
  4. Refractive error

Explanation

Intraocular pressure is the only modifiable risk factor with strong evidence for slowing progression, and higher baseline and follow-up pressures predict faster field loss. Other recognised risk factors include age, thin central corneal thickness, disc haemorrhage and family history. Refractive error, iris colour and height are not established predictors.

Question 46Glaucoma

A patient on maximal tolerated medical therapy has progressive glaucomatous field loss. Which surgical option offers the greatest IOP reduction?

  1. Observation with repeat fields
  2. Selective laser trabeculoplasty
  3. Trabeculectomy with mitomycin C Correct answer.
  4. Argon laser peripheral iridoplasty

Explanation

Trabeculectomy with antimetabolite achieves the largest sustained IOP reduction and is the standard incisional procedure for progressive glaucoma despite medical therapy. Selective laser trabeculoplasty gives a smaller reduction and is often used earlier. Iridoplasty is for angle closure, not open-angle glaucoma.

Question 47Glaucoma

Which finding suggests a diagnosis of normal-tension glaucoma rather than primary open-angle glaucoma?

  1. IOP above 30 mmHg with a normal disc
  2. Cupping reversed by IOP lowering
  3. Open angle with heavy trabecular pigmentation
  4. IOP consistently below 21 mmHg with glaucomatous disc and field damage Correct answer.

Explanation

Normal-tension glaucoma is defined by glaucomatous optic neuropathy and field loss with untreated IOP within the statistically normal range on repeated diurnal measurement. Other causes such as previous acute pressure spikes, steroid response and ischaemic optic neuropathy must be excluded. Elevated IOP defines ocular hypertension or POAG.

Question 48Glaucoma

Which corneal measurement should be considered when interpreting applanation tonometry in a patient with suspected glaucoma?

  1. Central corneal thickness Correct answer.
  2. Corneal diameter
  3. Tear film osmolarity
  4. Corneal sensitivity

Explanation

Goldmann applanation tonometry is calibrated for an average central corneal thickness of about 545 micrometres. Thin corneas underestimate and thick corneas overestimate true IOP, and thin central corneal thickness is itself a risk factor for glaucoma progression. Corneal diameter, sensitivity and tear osmolarity do not adjust applanation readings.

Question 49Glaucoma

Which mechanism underlies neovascular glaucoma in a patient with proliferative diabetic retinopathy?

  1. Fibrovascular membrane contraction causing synechial angle closure Correct answer.
  2. Pupillary block from a shallow anterior chamber
  3. Trabecular obstruction by pigment
  4. Ciliary body shutdown

Explanation

Retinal ischaemia drives VEGF release, causing rubeosis iridis and fibrovascular tissue in the angle. Contraction of this membrane produces peripheral anterior synechiae and synechial angle closure, raising IOP. Treatment targets the underlying ischaemia with panretinal photocoagulation and anti-VEGF therapy.

Question 50Glaucoma

A patient with a history of acute angle-closure attack in one eye is being counselled. Which statement about the fellow eye is correct?

  1. It should receive long-term topical steroids
  2. It should be treated with trabeculectomy
  3. It has a high risk of a similar attack and should receive prophylactic iridotomy Correct answer.
  4. It is at low risk and needs no intervention

Explanation

The fellow eye of a patient with acute angle closure shares the same anatomical predisposition and carries a high risk of a similar attack. Prophylactic laser peripheral iridotomy is standard practice to prevent it. Trabeculectomy and steroids are not indicated prophylactically.