Board Certified Ophthalmologist Glaucoma Diagnosis and Management Questions and Answers — Questions and Answers
Question 1: A 68-year-old male with a history of primary open-angle glaucoma (POAG) presents for a follow-up visit. His intraocular pressure (IOP) is 18 mmHg in both eyes on a prostaglandin analog. Optical Coherence Tomography (OCT) of the retinal nerve fiber layer (RNFL) shows progressive thinning in the inferotemporal quadrant of the right eye compared to the previous year. Visual field testing remains reliable and full. What is the most appropriate next step in management?
- Continue current therapy and repeat testing in one year.
- Add a second IOP-lowering agent. (Correct answer)
- Discontinue the prostaglandin analog and switch to a beta-blocker.
- Perform a laser peripheral iridotomy.
Correct answer: Add a second IOP-lowering agent.
The presence of documented structural progression (RNFL thinning on OCT) despite an IOP within the 'normal' range indicates that the current therapy is insufficient to halt the disease. Lowering the IOP further is the primary goal to slow progression. Adding a second medication is the standard approach in this scenario. Continuing the current therapy would be inappropriate given the evidence of progression. Switching to a beta-blocker alone may not provide sufficient additional IOP lowering. A laser peripheral iridotomy is indicated for angle-closure glaucoma, not POAG.
Question 2: A 55-year-old hyperopic female presents to the emergency department with severe right eye pain, headache, nausea, and blurred vision with halos around lights. On examination, her IOP is 52 mmHg, the cornea is hazy, the pupil is mid-dilated and nonreactive, and the anterior chamber is shallow. Gonioscopy of the fellow eye reveals a narrow, occludable angle. What is the definitive treatment for this condition?
- Topical prostaglandin analog therapy
- Intravenous acetazolamide followed by oral therapy
- Laser peripheral iridotomy (Correct answer)
- Selective laser trabeculoplasty (SLT)
Correct answer: Laser peripheral iridotomy
This patient presents with classic signs and symptoms of acute angle-closure glaucoma, which is an ophthalmic emergency. While initial management involves medically lowering the IOP with agents like topical beta-blockers, alpha-agonists, and systemic carbonic anhydrase inhibitors (acetazolamide), the definitive treatment to prevent recurrence and treat the underlying mechanism of pupillary block is a laser peripheral iridotomy (LPI). LPI creates an alternative pathway for aqueous humor to flow from the posterior to the anterior chamber, relieving the pressure gradient and allowing the peripheral iris to move away from the trabecular meshwork. SLT is used for open-angle glaucoma.
Question 3: Which of the following findings is most characteristic of Normal-Tension Glaucoma (NTG)?
- Intraocular pressures consistently above 25 mmHg.
- Optic disc hemorrhages. (Correct answer)
- A deep, centrally located visual field defect.
- Peripheral anterior synechiae on gonioscopy.
Correct answer: Optic disc hemorrhages.
Normal-Tension Glaucoma (NTG) is characterized by glaucomatous optic neuropathy in the setting of statistically normal intraocular pressures. While many features overlap with POAG, optic disc hemorrhages (Drance hemorrhages) are found more frequently in patients with NTG and are often a sign of disease progression. Visual field defects in NTG are often closer to fixation than in POAG. High IOP is contrary to the definition of NTG. Peripheral anterior synechiae are a sign of angle-closure glaucoma.
Question 4: When interpreting a Humphrey Visual Field (HVF) 24-2 test for glaucoma, which of the following indices is most useful for identifying localized, focal defects characteristic of early glaucomatous damage?
- Mean Deviation (MD)
- Visual Field Index (VFI)
- Pattern Standard Deviation (PSD) (Correct answer)
- Fixation Losses
Correct answer: Pattern Standard Deviation (PSD)
The Pattern Standard Deviation (PSD) reflects the degree to which the shape of the patient's measured visual field departs from the normal, age-corrected hill of vision. A high PSD value indicates focal or localized loss, which is typical for early to moderate glaucoma, rather than a generalized depression of the entire field. The Mean Deviation (MD) represents the overall, average deviation from the norm and is more affected by diffuse loss, such as from a cataract. The Visual Field Index (VFI) is a staging index that expresses the amount of visual field loss as a percentage of a normal field. Fixation losses are a reliability index.
Question 5: A 72-year-old patient with moderate primary open-angle glaucoma is being monitored for progression. Which combination of tests provides the most comprehensive information to assess for glaucomatous progression?
- Tonometry and gonioscopy
- Corneal pachymetry and fundus photography
- Serial tonometry and family history review
- Stereoscopic optic disc photography/OCT and automated perimetry (Correct answer)
Correct answer: Stereoscopic optic disc photography/OCT and automated perimetry
Monitoring glaucoma progression requires assessing both structural (optic nerve and RNFL) and functional (visual field) changes over time. Stereoscopic optic disc photography or, more commonly now, Optical Coherence Tomography (OCT) provides objective, quantitative data on structural changes. Standard automated perimetry (visual field testing) assesses functional loss. Using both tests together provides complementary information, as structural changes can sometimes precede functional loss and vice versa, especially in different stages of the disease. The other options are important for initial diagnosis or risk assessment but are not the primary methods for monitoring progression.
Question 6: According to the American Academy of Ophthalmology (AAO) Preferred Practice Pattern for Primary Open-Angle Glaucoma, what is a reasonable initial target for intraocular pressure (IOP) reduction in a newly diagnosed patient?
- A reduction of 5-10% from baseline
- A target IOP below 15 mmHg for all patients
- A reduction of 20-30% from baseline (Correct answer)
- A target IOP equal to the population mean of 16 mmHg
Correct answer: A reduction of 20-30% from baseline
The AAO Preferred Practice Pattern for POAG states that a reasonable initial treatment goal is to lower the IOP by 20-30% below the baseline measurement. This target can then be adjusted based on the individual patient's disease severity, rate of progression, and other risk factors. A fixed numerical target is less individualized than a percentage reduction from the patient's specific baseline pressure. A 5-10% reduction is generally considered insufficient for meaningful clinical effect.
Board Certified Ophthalmologist Glaucoma Diagnosis and Management Questions and Answers
A 68-year-old male with a history of primary open-angle glaucoma (POAG) presents for a follow-up visit.
His intraocular pressure (IOP) is 18 mmHg in both eyes on a prostaglandin analog.
Optical Coherence Tomography (OCT) of the retinal nerve fiber layer (RNFL) shows progressive thinning in the inferotemporal quadrant of the right eye compared to the previous year.
Visual field testing remains reliable and full.
What is the most appropriate next step in management?