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OP7.1-5 | Glaucoma — Practice Quiz
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A 3-week-old infant is brought with excessive tearing, photophobia, and a noticeably large left eye. Examination under anaesthesia reveals a corneal diameter of 14 mm, intraocular pressure of 32 mmHg, and an abnormal trabecular meshwork on gonioscopy. What is the most appropriate next step?
Correct. Surgery (goniotomy or trabeculotomy) is the definitive first-line treatment for primary congenital glaucoma. Medical drops are a temporary bridge, not definitive care.
Primary congenital glaucoma is treated surgically — goniotomy or trabeculotomy — not medically. Medical therapy is used only as a temporary bridge before surgery.
Incorrect. In primary congenital glaucoma, surgery is the treatment of choice — not medical management. A corneal diameter of 14 mm in a neonate with raised IOP and trabeculodysgenesis requires surgical angle intervention (goniotomy or trabeculotomy) as first-line definitive treatment.
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The classic triad of primary congenital glaucoma consists of which combination of features?
Correct. The classic triad is epiphora, photophobia, and blepharospasm. Buphthalmos and Haab striae are additional findings but not the presenting triad.
The classic presenting triad of primary congenital glaucoma is epiphora (watering), photophobia, and blepharospasm — all driven by the raised IOP irritating the immature cornea.
Incorrect. The classic triad of primary congenital glaucoma is epiphora (excessive tearing), photophobia, and blepharospasm — these three features driven by elevated IOP irritating the infant cornea are the hallmark presentation. Buphthalmos is a sign, not part of the triad.
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A 58-year-old man presents for a routine eye check. He has no visual complaints. Examination reveals an IOP of 26 mmHg bilaterally, a cup-to-disc ratio of 0.7 with inferior rim thinning, and an open angle on gonioscopy. Automated perimetry shows an arcuate scotoma. Which drug class is the most appropriate first-line treatment?
Correct. Prostaglandin analogues (latanoprost, bimatoprost, travoprost) are first-line for POAG — they produce the greatest IOP reduction (25-33%) and have once-daily dosing. They are contraindicated in angle-closure, not in POAG.
Prostaglandin analogues are the most potent IOP-lowering agents (25-33% reduction) and are the preferred first-line therapy for POAG in most guidelines. They act by increasing uveoscleral outflow.
Incorrect. The first-line medical treatment for POAG is a topical prostaglandin analogue (latanoprost, bimatoprost, or travoprost). These provide the greatest IOP reduction (25-33%) via increased uveoscleral outflow and have once-daily dosing. Timolol is an alternative first-line option, but prostaglandins are preferred in current guidelines.
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In primary open-angle glaucoma, the ISNT rule helps assess optic disc health. Which statement correctly describes what this rule states about a normal optic disc?
Correct. ISNT: Inferior is thickest, then Superior, then Nasal, then Temporal — in a healthy optic disc. Loss of this pattern, especially inferior rim thinning, is an early glaucomatous sign.
The ISNT rule (Inferior greater than Superior greater than Nasal greater than Temporal) describes the normal neuroretinal rim thickness hierarchy. Glaucoma preferentially damages the inferior and superior poles first, violating this rule.
Incorrect. The ISNT rule states the neuroretinal rim in a normal disc is thickest Inferiorly, then Superiorly, then Nasally, then Temporally. Glaucoma preferentially attacks the inferior and superior poles, causing these sectors to thin disproportionately and violate the ISNT pattern.
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A 55-year-old woman presents as an emergency with a sudden onset of severe right eye pain, headache, nausea, and vomiting. She reports seeing coloured haloes around lights. On examination the right eye is red, the cornea is hazy, the pupil is mid-dilated and fixed, and IOP is 58 mmHg. What is the correct immediate management?
Correct. This is an acute angle-closure crisis requiring immediate multi-drug attack: systemic acetazolamide, IV mannitol (if IOP >50), topical timolol, and pilocarpine 2% to constrict the pupil and mechanically open the angle. Latanoprost alone (a prostaglandin) would be inadequate and inappropriate here.
Acute PACG is a medical emergency. Immediate treatment combines systemic IOP reduction (IV/oral acetazolamide, IV mannitol if severe), topical IOP-lowering agents (timolol, apraclonidine), and topical pilocarpine 2% to constrict the pupil and break pupil block — followed by definitive laser peripheral iridotomy once the cornea clears.
Incorrect. This is an acute PACG attack — a sight-threatening emergency. Immediate management requires intravenous acetazolamide 500 mg, topical pilocarpine 2% (to constrict the pupil and relieve pupil block), topical timolol, and IV mannitol if IOP remains very high. Once IOP is controlled and the cornea clears, definitive laser peripheral iridotomy is performed.
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Which anatomical mechanism is the fundamental pathophysiological basis of primary angle-closure glaucoma?
Correct. Pupil block is the core mechanism: aqueous accumulates in the posterior chamber, bowing the peripheral iris forward to obstruct the trabecular meshwork, causing acute IOP rise.
PACG is caused by pupil block — aqueous cannot flow freely from the posterior to anterior chamber, causing posterior chamber pressure to rise, the iris to bow forward (iris bombe), and the trabecular meshwork to become occluded by the peripheral iris.
Incorrect. The fundamental mechanism in PACG is pupil block. Aqueous cannot flow freely through the pupillary aperture; posterior chamber pressure builds, the peripheral iris bows forward (iris bombe), and occludes the trabecular meshwork. This is fundamentally different from POAG, where the angle remains open but the trabecular meshwork offers increased resistance.
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A patient on long-term topical steroid eyedrops for allergic conjunctivitis is found to have an IOP of 34 mmHg with an open angle on gonioscopy. There is no family history of glaucoma. Which type of secondary glaucoma does this represent?
Correct. Long-term topical (or systemic) steroids cause open-angle secondary glaucoma by reducing trabecular meshwork phagocytosis and increasing outflow resistance. The key feature is an open angle on gonioscopy despite elevated IOP.
Steroid-induced glaucoma is a common secondary open-angle glaucoma. Corticosteroids decrease phagocytic activity of trabecular meshwork cells, causing glycosaminoglycan accumulation and increased outflow resistance. Management requires steroid withdrawal and IOP-lowering agents.
Incorrect. This is steroid-induced glaucoma — a secondary open-angle glaucoma caused by corticosteroid-induced reduction in trabecular meshwork phagocytic activity, leading to glycosaminoglycan accumulation and raised outflow resistance. Phacolytic and phacomorphic glaucomas are lens-induced; neovascular glaucoma is caused by fibrovascular membrane over the angle (commonly in diabetic retinopathy or CRVO).
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A 70-year-old man has a mature cataract causing his lens to enlarge and push the iris forward, narrowing the anterior chamber angle and causing elevated IOP. Which secondary glaucoma mechanism does this represent, and what is the definitive treatment?
Correct. Phacomorphic glaucoma is lens-induced angle closure due to a physically enlarged, swollen lens. MORPHIC = MASSIVE lens MECHANICAL push. Urgent lens extraction is the definitive treatment. Laser PI may temporarily help, but lens removal is curative.
Phacomorphic glaucoma results from a swollen lens mechanically displacing the iris forward, causing angle closure — a closed-angle mechanism. The mnemonic is MORPHIC = MASSIVE lens = MECHANICAL pushing. Definitive treatment is cataract extraction. Phacolytic glaucoma (open-angle) is caused by lens protein leaking through an intact capsule and clogging the trabecular meshwork.
Incorrect. This is phacomorphic glaucoma — a lens-induced closed-angle secondary glaucoma caused by a swollen lens mechanically pushing the iris forward. The definitive treatment is urgent cataract extraction (lens removal). Phacolytic glaucoma, by contrast, is open-angle: protein leaks through an intact mature cataract capsule, clogs the trabecular meshwork, and requires the same treatment (lens extraction) but via a completely different mechanism.
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When counselling a patient newly diagnosed with primary open-angle glaucoma, which statement is most important for them to understand about their eye drops?
Correct. The critical counselling message: glaucoma drops do not restore lost vision — they prevent further loss by controlling IOP. Glaucomatous optic nerve damage is irreversible. The patient must understand this to appreciate why lifelong adherence is essential even when they feel no symptoms.
POAG causes irreversible visual field loss. IOP-lowering drops prevent further progression but cannot restore already damaged nerve fibres. The most powerful counselling message is: the drops protect the vision you still have. Lifelong use is required.
Incorrect. The most important counselling point for a newly diagnosed POAG patient is that their drops will NOT restore already lost vision — glaucomatous optic nerve damage is irreversible — but they WILL prevent further loss if taken consistently. POAG is asymptomatic until late; patients must understand that the drops protect remaining vision even when they feel completely normal.
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A patient with POAG asks whether surgery (trabeculectomy) will permanently cure them and allow them to stop all eye drops. Which is the most accurate response?
Correct. Trabeculectomy is an effective IOP-lowering surgical option for POAG but requires ongoing follow-up as blebs can scar and fail. Patients need lifelong monitoring of IOP, optic disc, and visual fields regardless of treatment type.
Trabeculectomy creates a bleb through which aqueous drains subconjunctivally. It can significantly reduce IOP and dependence on drops, but it is not a permanent cure: blebs can fail, and lifelong optic disc and visual field monitoring is essential in all glaucoma patients regardless of treatment modality.
Incorrect. Trabeculectomy is an effective surgical intervention for POAG that can substantially reduce IOP, sometimes eliminating the need for drops. However, it is not a permanent cure — filtering blebs can fail over months to years, and all glaucoma patients require lifelong monitoring of IOP, optic disc, and visual fields regardless of treatment modality.
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