Free ABO Glaucoma Diagnosis and Management Questions and Answers — Questions and Answers
Question 1: A 68-year-old male with primary open-angle glaucoma is being monitored for progression. His intraocular pressure is stable on a prostaglandin analog. Which finding on spectral-domain optical coherence tomography (SD-OCT) of the retinal nerve fiber layer (RNFL) is most indicative of early glaucomatous progression?
- Diffuse thinning of the entire RNFL
- Focal thinning of the inferotemporal quadrant that crosses the horizontal midline
- An increase in the overall signal strength of the scan
- Localized thinning of the inferotemporal or superotemporal quadrant that respects the horizontal midline (Correct answer)
Correct answer: Localized thinning of the inferotemporal or superotemporal quadrant that respects the horizontal midline
Early glaucomatous damage typically manifests as localized thinning of the retinal nerve fiber layer, most commonly in the inferotemporal and superotemporal arcuate bundles. This damage respects the horizontal raphe. Diffuse thinning is less specific and can be seen in other conditions or advanced disease. Crossing the midline is not a typical pattern for early glaucoma. Increased signal strength is a measure of scan quality, not a sign of pathology.
Question 2: A 55-year-old female presents with sudden, severe right eye pain, blurred vision, and nausea. On examination, her intraocular pressure (IOP) is 58 mmHg, the cornea is hazy, and the pupil is mid-dilated and nonreactive. Gonioscopy of the left eye reveals a narrow, occludable angle. What is the most appropriate definitive initial treatment for the affected right eye after the acute attack is medically controlled?
- Topical prostaglandin analog therapy
- Selective laser trabeculoplasty (SLT)
- Laser peripheral iridotomy (LPI) (Correct answer)
- Trabeculectomy
Correct answer: Laser peripheral iridotomy (LPI)
This patient is experiencing an acute angle-closure glaucoma attack. The definitive treatment to relieve pupillary block and prevent recurrence is a laser peripheral iridotomy (LPI). This procedure creates a new channel for aqueous humor to flow from the posterior to the anterior chamber. Prostaglandin analogs are generally used for open-angle glaucoma. SLT is used for open-angle glaucoma and is not effective for angle-closure. Trabeculectomy is a surgical option for more advanced or uncontrolled glaucoma, not the initial definitive procedure for acute angle-closure.
Question 3: Which of the following classes of topical glaucoma medications primarily works by increasing the uveoscleral outflow of aqueous humor?
- Beta-blockers
- Prostaglandin analogs (Correct answer)
- Alpha-adrenergic agonists
- Carbonic anhydrase inhibitors
Correct answer: Prostaglandin analogs
Prostaglandin analogs (e.g., latanoprost, travoprost, bimatoprost) are a first-line treatment for open-angle glaucoma and lower intraocular pressure primarily by increasing the outflow of aqueous humor through the uveoscleral pathway. Beta-blockers and carbonic anhydrase inhibitors decrease aqueous production, while alpha-adrenergic agonists both decrease production and increase trabecular outflow.
Question 4: A 62-year-old patient is diagnosed with normal-tension glaucoma (NTG). Their intraocular pressures are consistently 15-17 mmHg in both eyes. Humphrey Visual Field testing shows a dense superior arcuate scotoma in the right eye. According to the Collaborative Normal Tension Glaucoma Study (CNTGS), what is the recommended management approach?
- Observation without treatment, as the IOP is within the normal range.
- Initiation of a topical beta-blocker to lower IOP by 10%.
- Surgical intervention with trabeculectomy as the first-line treatment.
- Lowering the intraocular pressure by at least 30% from baseline. (Correct answer)
Correct answer: Lowering the intraocular pressure by at least 30% from baseline.
The Collaborative Normal Tension Glaucoma Study (CNTGS) demonstrated that lowering the IOP by at least 30% significantly slowed the rate of visual field progression in patients with NTG. Even though the initial pressure is within the 'normal' range, reducing it further is the only proven treatment to slow disease progression. Observation is only appropriate if there is no evidence of progression. A 10% reduction is less than the target established by the CNTGS, and surgery is typically reserved for cases that progress despite medical or laser therapy.
Question 5: When interpreting a Humphrey Visual Field (HVF) 24-2 test for a glaucoma suspect, which of the following patterns is most characteristic of early glaucomatous damage?
- A central scotoma
- A bitemporal hemianopsia
- A nasal step respecting the horizontal midline (Correct answer)
- An enlarged blind spot
Correct answer: A nasal step respecting the horizontal midline
Early glaucomatous visual field defects typically correspond to the pattern of nerve fiber layer loss. A nasal step, which is a scotoma just above or below the horizontal midline in the nasal field, is a classic early sign. This occurs due to damage to the arcuate nerve fibers. A central scotoma is more typical of macular disease or advanced glaucoma. Bitemporal hemianopsia suggests a chiasmal lesion. An enlarged blind spot can be seen in glaucoma but is less specific than a nasal step.
Question 6: A 70-year-old patient with pseudoexfoliation glaucoma has an intraocular pressure of 28 mmHg in the right eye despite maximal tolerated medical therapy with a prostaglandin analog, a beta-blocker, and a carbonic anhydrase inhibitor. Which of the following is the most appropriate next step in management?
- Add a fourth medication, such as a miotic.
- Switch the prostaglandin analog to a different brand.
- Perform selective laser trabeculoplasty (SLT). (Correct answer)
- Continue to monitor the patient on the current regimen.
Correct answer: Perform selective laser trabeculoplasty (SLT).
This patient has inadequately controlled IOP on maximal medical therapy. Selective laser trabeculoplasty (SLT) is a well-established and effective option to further lower IOP when medications are insufficient or not tolerated. Adding a fourth medication often has limited additional effect and increases the complexity and potential for side effects. Switching between prostaglandin analogs may offer a small benefit but is less likely to achieve the required pressure reduction than SLT. Continuing to monitor without intervention is inappropriate given the high IOP and risk of progression.
Free ABO Glaucoma Diagnosis and Management Questions and Answers
A 68-year-old male with primary open-angle glaucoma is being monitored for progression.
His intraocular pressure is stable on a prostaglandin analog.
Which finding on spectral-domain optical coherence tomography (SD-OCT) of the retinal nerve fiber layer (RNFL) is most indicative of early glaucomatous progression?